VARC Marine Control Units

MARINE

CONTROL UNITS

VARC MODELS

VARC Chiller Controls

WARNING
Cancer and Reproductive Harm
www.P65Warnings.ca.gov

L-3499 | Form No. 338208 20200323 | ©2020 Dometic Corporation

1 Explanation of Symbols and Safety Instructions

This manual has safety information and instructions to
help you eliminate or reduce the risk of accidents and
injuries.

1.1 Recognize Safety Information
This is the safety alert symbol. It is used to alert
you to potential physical injury hazards. Obey all
safety messages that follow this symbol to avoid
possible injury or death.

1.2 Understand Signal Words
A signal word will identify safety messages and property
damage messages, and also will indicate the degree or
level of hazard seriousness.

DANGER!
Indicates a hazardous situation that, if not avoided,
will result in death or serious injury.

WARNING
Indicates a hazardous situation that, if not avoided,
could result in death or serious injury.

CAUTION
Indicates a hazardous situation that, if not avoided,
could result in minor or moderate injury.

NOTICE: Used to address practices not related to
physical injury.

Indicates additional information that is not related
to physical injury.

1.3 Supplemental Directives
To reduce the risk of accidents and injuries, please
observe the following directives before proceeding to
install or operate this appliance:

• Read and follow all safety information and
  instructions.

• Read and understand these instructions before
  installing or operating this product.

• The installation must comply with all applicable local
  or national codes, including the latest edition of the
  following standards:
  –– American Coast Guard Standards (CG-ENG)
  –– American Boat and Yacht Council (ABYC)
  –– ANSI/NFPA70, National Electrical Code (NEC)

1.4 General Safety Messages
WARNING: ELECTRICAL SHOCK, FIRE, AND/
OR EXPLOSION HAZARD. Failure to obey the
following warnings could result in death or
serious injury:

• Use only Dometic replacement parts and
  components that are specifically approved for use
  with the appliance.

• Avoid improper installation, adjustment, alterations,
  service, or maintenance of the appliance. Service and
  maintenance must be done by a qualified service
  person only.

• Do not modify this product in any way. Modification
  can be extremely hazardous.

• Use care when diagnosing and/or adjusting
  components on a powered unit.

2 General Information

The Dometic Variable Capacity Chiller (VARC) includes
a microcontroller-based unit to control multiple chillers.
The multiple-chiller design provides flexibility in the
control application and improved controls and system
protection.

The images used in this document are for reference
purposes only. Components and component
locations may vary according to specific product
models. Measurements may vary ±0.38 in.
(10 mm).

2.1 Product Description
This section describes some of the key design features
of the VARC, the control application, the LCD and touch
screen displays, and the inputs and outputs.

2.1.1 VARC Design Features
The VARC uses a precision Proportional Integral
Derivative (PID) loop control algorithm that manages
the capacity requirements of the system by modulating
the compressor speed and balancing chiller output with
the required load. The PID system differs greatly from
the on/off control of a standard chiller system, as the
PID modulates the speed of the compressor to increase
or decrease its capacity allowing for reduced current
consumption by the electrical system. This smooth
operation eliminates large swings in current on the
generator. This completely variable capacity chiller uses
an inverter to modulate the speed of the compressor to
achieve the desired chilled water setpoint. This allows
the compressor to run at a minimum speed of 30 Hz to a
maximum of 240 Hz depending on compressor model.

The VARC also uses the advanced technology of an
Electronic Expansion Valve (EEV). This provides more
precise control of superheat across a broad range of
conditions with no erratic swings as the valve reacts to
temperature and pressure changes (no “hunting”). Using
an advanced algorithm, the VARC maintains superior
superheat control over extreme operating conditions.

The VARC controller is internally grounded with isolation
between inputs and outputs.

The output relays offer double isolation so that different
voltages can be used for groups of relays.
For temperature measurements, the system uses NTC
type 10K@77° thermistors.

For both suction and discharge monitoring, the system
uses ratiometric 0–650 PSI (45 bar) range pressure
transducers.

2.1.2 VARC Control Application
The built-in VARC control application supports the
following features:

• Selection and sequencing of up to six chillers

• Selection and sequencing of one Chilled Water Pump
  (CWP) and one or more Sea Water Pumps (SWP)

• Selection and sequencing of up to six electric heaters

• Sequencing of devices for run time equalization

• Alarms and interlocks

• Load shedding

• Troubleshooting help

Sequencing for chillers, pumps, and heaters is the order
in which they start up and turn off. Sequencing is based
on run time, which is the amount of hours a specific
compressor, pump, or heater has run.

The VARC is factory programmed with the options
enabled for that system. Although the system offers
flexibility, these options can be enabled only by a factory
representative. Users can select Normal, Econo, or
Boost mode operation in a single-stage configuration.

2.1.3 PGD1 LCD Display
The PGD1 provides an LCD display and six buttons for
navigating the control software.

1 PGD1 LCD Display Components
1 Alarm r Scroll Up
2 Program t Enter
3 Escape y Scroll Down

2.1.4 PLDPRO LCD Display
The PLDPRO provides an LCD display and six buttons for
navigating the control software.

2 PLDPRO LCD Display Components
1 Alarm
2 Program
3 Escape
4 Scroll Up
5 Enter
6 Scroll Down

2.1.5 LCD Buttons
The buttons on the PGD1 and PLDPRO operate as
described in the following table:

This button flashes red if there is an
active alarm. Pressing this button
displays the active alarm screen. See
“Viewing Alarms for Each Stage” on
page 28.

Program|

This button displays the system menus.
Use the scroll buttons to step through
the options. Press the Enter button to
select an option.

Escape|

This button exits the current screen and
displays the previous screen. Pressing
this button multiple times displays the
Main screen.

Scroll Up and
Scroll Down|

These buttons step through available
menu options, change values in fields
such as setpoints, and navigate from
page to page when the flashing cursor
is in the upper-left corner.

Enter|

This button confirms menu option
selections. Pressing Enter repeatedly
moves the cursor the upper-left corner.

2.1.6 Touch Screen
This section describes the navigation buttons on the
Main screen.

3 Touch Screen: Main Screen with Navigation Buttons.
The navigation buttons function as follows:

• Enable: Enter setpoints, monitor chilled water
  temperatures and monitor pump current information.

• Summary: View the state of HP, EH, FS, and water
  temperature for all available stages. Tapping a stage
  displays additional information on that stage.

• Chiller Stage: Monitors the refrigerant and chilled
  water circuits. Provides hotspot icons that display
  additional information when selected. Different icons
  appear depending which options are installed. The
  Forward and Back buttons navigate between stages.

• Trends: View a graphical display of water
  temperature, water pressure, and compressor current.
  Data is downloadable to a USB memory stick.

• Alarms: View and clear alarms. Pressing the buttons
  at the top-right displays alarm history and other alarm
  information.

• Remote Support: Enable third-party technical
  support to view your system over an Internet
  connection using a VNC (Virtual Network
  Computing) server.

2.2 Inputs and Outputs
The VARC allows you to monitor analog inputs, digital inputs, and relay outputs to determine the status of the system.

2.2.1 Analog Inputs
If a temperature sensor is defective or not connected, the VARC generates an alarm for that sensor.

Chilled Water Return
Temperature Sensor| AI-1| B1|

The chilled water supply sensor is continuously monitored whether in Cooling, Reverse Cycle,
or Electric Heat mode. It detects a high-temperature condition in the supply water from the
chiller. If the chilled water temperature is greater than or equal to 125 °F (52 °C), the following
occurs:
• In Reverse Cycle mode, all enabled compressor relays are de-energized, turning off the
compressors.
• In Electric Heating mode, all enabled heater relays are de-energized, turning off the
heating elements.
• A high temperature fault is generated.
• The compressor or electric heat relay re-energizes when the temperature drops to 110 °F
(43 °C).
You must acknowledge and clear the fault prior to re-enabling the VARC or the disabled
stage. See “Viewing Alarms for Each Stage” on page 28.

Freeze Temperature
Setpoint| AI-2| B2|

The chilled water supply sensor is continuously monitored whether in Cooling, Reverse Cycle,
or Electric Heat mode. It detects a freeze condition in the supply water of the chiller. If the
chilled water temperature is equal to or less than 36 °F (2 °C), the following occurs:
• The compressor relay is de-energized, shutting off the compressor.
• A low temperature fault is generated.
• The compressor relay re-energizes when the temperature reaches 42 °F (6 °C).
You must acknowledge and clear the fault prior to re-enabling the VARC or the disabled
stage. See “Viewing Alarms for Each Stage” on page 28.

Condenser Freeze
Protection| AI-3| B3|

The condenser outlet refrigerant temperature sensor monitors the condenser coil
temperature. In Heat mode, if the coil temperature drops below 30 °F (-1 °C), the VARC
automatically lowers the speed of the compressor to half the speed that it was currently
running. While performing this operation, the display indicates Freeze Defrost.

Suction Pressure 1| AI-6| B6|

The VARC continuously monitors the suction pressure. If the suction pressure is below the
alarm setpoint for longer than the programmed time delay, a Low Suction Pressure fault is
generated.
You must acknowledge and clear the fault prior to re-enabling the VARC or the disabled stage
See “Viewing Alarms for Each Stage” on page 28.

Discharge Pressure 1| AI-7| B7|

The VARC continuously monitors the discharge pressure. If the discharge pressure is above
the alarm setpoint for longer than the programmed time, a High Discharge Pressure fault is
generated.
You must acknowledge and clear the fault prior to re-enabling the VARC or the disabled
stage. See “Viewing Alarms for Each Stage” on page 28.

Pump Current
Monitoring
(Optional) 1| AI-9
(CW)
AI-10
(SW)| B-9 (CW)
B-10 (SW)|

Pump current monitoring for the chilled water and Sea Water Pump (SWP) is an optional
feature. It requires the medium-sized PLC, instead of the standard smaller version. With this
option, you can view the current draw from each pump on the PGD1 display and the touch
screen.

1 The VARC has a proprietary algorithm that keeps the system from turning off immediately for low pressure or high pressure. The VARC gradually reduces its speed to compensate for low or high pressure conditions.

2.2.2 Digital Inputs
Digital inputs are used to monitor the status of the VARC protection circuits. At powerup, all discrete inputs are checked
before the system is enabled. Any faults detected on startup must be verified and cleared via the VARC before the system
will start normal operation. For information on clearing alarms, see “Viewing Alarms for Each Stage” on page 28.

Refrigerant High Side
Pressure Limit| DI-1| DI-1|

If the high pressure switch is tripped and turns off the compressor, the VARC acknowledges
an open circuit and generates a High Discharge Pressure fault. The VARC will not allow the
compressor relay to be re-energized until the high pressure switch is in the closed position.
You must acknowledge and clear the fault prior to re-enabling the VARC or the disabled
stage. See “Viewing Alarms for Each Stage” on page 28.

Econo Mode Selection| DI-2| DI-2|

This optional input is used to put the VARC into Econo mode. While Econo mode is enabled
by this input, the VARC cannot be put into Normal or Boost mode.

Chilled Water Flow
Switch| DI-3| DI-3|

With the VARC in either Heat or Cool mode, the Flow switch must be closed prior to system
starting or a stage being enabled. In operation, if flow is lost for more than 10 consecutive
seconds, the following occurs:
• The compressor or heat relay is disabled for the stage that has lost flow.
• A Chilled Water Flow fault is generated.
• The VARC goes into lockout.
• A manual restart is required, after the system initiates, retries, and fails or exceeds timeout.
You must acknowledge and clear the fault prior to re-enabling the VARC or the disabled
stage. See “Viewing Alarms for Each Stage” on page 28.

Load Shedding Input| DI-4| DI-4|

The load shedding standard input is activated with a 230 V signal. When load shedding
becomes active, the VARC shuts off the compressor and maintains that state until the load
shedding input is disabled.
In a multi-stage operation, load shedding shuts down the stage with the highest run hours.
Every unit has a load shed input. The number of load shedding signals received (one per unit)
determines how many units are shut off according to run hours.

Electric Heat (E. H.)
Flow Switch| DI-5| DI-5|

This optional switch is enabled through the factory settings. With the VARC in either Heat or
Cool mode, the Flow switch must be closed prior to system starting or a stage being enabled.
In operation, if flow is lost for more than 10 consecutive seconds, the following occurs:
• The electric heat is disabled for the stage that has lost flow.
• An Electric Heat Flow fault is generated.
• The VARC goes into lockout.
• A manual restart is required, after the system initiates, retries, and fails or exceeds timeout.
You must acknowledge and clear the fault prior to re-enabling the VARC or the disabled
stage. See “Viewing Alarms for Each Stage” on page 28.

Cool Mode Selection
Switch| DI-6| DI-6|

These switches allow for remote mode control. When using digital input mode selection, the display cannot be used to change mode, but all other functions on the display are available.

Heat Mode Selection switches| DI-7| DI-7

2.2.3 Digital Relay Outputs
If a temperature sensor is defective or not connected, the VARC generates an alarm for that sensor.

Provides switched power to the contactor coils for the Sea Water Pump.

CWP| DO-2| NO2|

Provides switched power to the contactor coils for the Chilled Water Pump.

Reversing Valve (RV)| DO-3| NO3|

Provides switched power to the coils for the Reversing Valve.

Electric Heat (EH)| DO-4| DO-4|

Provides switched power to the contactor coils for electric heat.

Not used.| DO-5| DO-5|

This output is not used.

Not used.| DO-6| DO-6|

This output is not used.

Fault Alarm| DO-7| NO7/NC7|

Provides a Normally Open (NO) contact point, which is closed for any fault condition. You can
use this output to power a light, relay, or interface to a ship’s monitoring system. The output on
this terminal is 230 VAC.

2.2.4 Analog Outputs
The analog outputs are not used.

Output I/O # Board I/O Description
Not used AO-1 Y1 This output is not used.
Not used AO-2 Y2 This output is not used.
Not used AO-3 Y3 This output is not used.

2.3 Default Parameters
The following table lists factory defaults for the compressor, inverter, and econo mode setpoint parameters (for other
VARC models, contact the factory).

Model Compressor Inverter Part Number
VARCX48 5KD184XAB21 PSD1 12 Amp
VARCX60 TNB306FPGMT PSD1 12 Amp
VARCX72 5JD420XAA22 PSD1 16 Amp
VARCX120
208–230V / 1PH SIAM ANB66FVCMT PSD2 30 Amp 200V
208–230V / 3PH SIAM ANB66FVCMT PSD2 40 Amp 200V
380–460V / 3PH SIAM ANB66FVQMT PSD1 40 Amp 400V
The following table lists factory defaults for all other parameters (for other VARC models, contact the factory).

Parameter VARCX48 VARCX60 VARCX72 VARCX120 Data Type
General Settings
Cooling Setpoint CCW Return 48 48 48 48 Degrees F
Cooling Setpoint CCW Supply 43 43 43 43 Degrees F
Heating Setpoint 110 110 110 110 Degrees F
Econo Mode 65% 65% 65% 65% Percent
Superheat Setpoint
Cool and Heat 10 10 10 10 Degrees F

Parameter VARCX48 VARCX60 VARCX72 VARCX120 Data Type
Condenser Frost Protection
Cond Setpoint 30 30 30 30 Degrees F
Cond Band 2.5 2.5 2.5 2.5 Degrees F
Comp Speed 60 40 40 40 RPS
Compressor PID
Cntrl P P P P
K 50 50 50 50
Chilled Water High Temperature Limit Alarm
Setpoint 125 125 125 125 Degrees F
Off Band (SP-) 15 15 15 15 Degrees F
Retries 6 6 6 6
Retry Timeout 30 30 30 30 Minutes
Retry Delay 120 120 120 120 Seconds
Chilled Water Freeze Limit Alarm
Setpoint 36 36 36 36 Degrees F
Off Band (SP+) 5.4 5.4 5.4 5.4 Degrees F
Retries 6 6 6 6
Retry Timeout 10 10 10 10 Minutes
Retry Delay 120 120 120 120 Seconds
Chilled Water Flow Alarm
Retries 6 6 6 6
Retry Timeout 10 10 10 10 Minutes
Retry Delay 120 120 120 120 Seconds
High Discharge Pressure Alarm
Retries 6 6 6 6
Retry Timeout 30 30 30 30 Minutes
Retry Delay 120 120 120 120 Seconds
High Pressure Switch Alarm
Retry 6 6 6 6
Retry Timeout 30 30 30 30 Minutes
Retry Delay 120 120 120 120 Seconds
Low Suction Alarm
Low Suction Pressure 60 60 60 60 PSI
Delay 180 180 180 180 Seconds
Retries 6 6 6 6
Retry Timeout 30 30 30 30 Minutes
Retry Delay 120 120 120 120 Seconds

Parameter VARCX48 VARCX60 VARCX72 VARCX120 Data Type
Inverter Alarm
Retry 15 15 15 15
Retry Timeout 60 60 60 60 Minutes
Retry Delay 300 300 300 300 Seconds
Configuration Menu
Temperature Units Degrees F Degrees F Degrees F Degrees F
Pressure Units PSI PSI PSI PSI

3 Intended Use

The VARC Chiller Control is a chiller control application
that supports touch screen and LCD interfaces.
This manual provides all necessary information for proper
operation of the VARC Chiller Control application.

NOTICE: Poor setup and misunderstood operating
parameters could result in unsatisfactory performance
and possibly failure.

The manufacturer accepts no liability for damage in the
following cases:

• Faulty assembly or connection

• Damage to the product resulting from mechanical
  influences and excess voltage

• Alterations to the product without express permission
  from the manufacturer

• Use for purposes other than those described in the
  operating manual

Dometic Corporation reserves the right to modify
appearances and specifications without notice.

4 Specifications

The following table lists electrical specifications,
environmental specifications, and touch screen
dimensions, and setpoint ranges.

Electrical
Line Voltage See Data Label
Frequency
Phase
Chilled Water Pump
Output
Sea Water Pump Output
Maximum Circuit Breaker
Size 1
Environmental
Maximum Ambient
Operating Temperature
140 °F (60 °C)
Touch Screen Dimensions
Height 5.79 in. (147 mm)
Width 7.36 in. (187 mm)
Depth 1.77 in. (45 mm)
1 Increase breaker size to include pump current if running pumps directly
from the system.

Setpoint Ranges1
Supply Control Return Control
Cooling 42 °F (6 °C) to
55 °F (13 °C)
48 °F (9 °C) to
55 °F (13 °C)
Heating 95 °F (35 °C) to
115 °F (46 °C)
95 °F (35 °C) to
120 °F (49 °C)
1 You cannot enter setpoint values outside of these ranges.

5 Installation and Setup

The VARC can be installed as a stand-alone chiller or as
part of a staged system. The factory default setting is as a
stand-alone chiller.
Installation for a staged system requires the following
steps:

1. Make the connections between each stage of the
   chilled water and sea water.

2. Make the network connections between each stage
   (physical and network addressing).

3. Check the firmware version.

4. Configure the remote control panel.

Chillers supplied on a frame package are configured and
wired as part of the build process.

As part of a correctly configured multi-stage system
there is no need to set differential/hysteresis settings.

5.1 Initial Wiring
WARNING: ELECTRICAL SHOCK HAZARD.
Exercise extreme care when working around
energized equipment. Failure to obey this warning
could result in death or serious injury.

1. Wire the sea water and chilled water pumps to
   VARC 1 (no need for pump relays) as follows:
   a. Remove the power cover.
   b. Connect the pumps to the terminals on the front
   of chiller 1, according to labeled connections.
   Note: Daisy chaining outputs is not recommended if the
   units have individual power sources. Verify the phase of
   power before daisy chaining the outputs.

2. Wire the network connections from the network
   connection ports (VARC 1 to VARC 2, VARC 2 to
   VARC 3, and so forth).
   Refer to the “Multi-stage Wiring” on page 14 for more
   information on wiring the stages.

1 Power Input
2 SW Pump (10 A max.)
3 CW Pump (10 A max.)
4 Network Connection and Touch Screen
5 Load Shed Switch
6 Elec. Heat Output

5.2 Multi-stage Wiring
The following diagram shows how to wire multiple VARC stages.

WARNING: ELECTRICAL SHOCK HAZARD.
Verify that all units’ power lines are in unison
phasing, in order to eliminate the potential for a
short circuit. Failure to obey this warning could
result in death or serious injury.

5.3 Touch Screen Connection
Make the following connections to the touch screen:
a. A 24 VDC supply to power the display
b. A three-core communication cable connected to serial port 1, not port 2
Terminate the three-core communication cable on
Terminal Bus 3 (Modbus Com) on VARC 1.

1 Power Input (24 V) 3 Connection Port for
Remote Connectivity
2 USB Port 4 Communication
Connection from PICO
(3 Conductor, 18 G
wire)

5.4 Firmware Verification
Chillers should come from the factory with the correct
firmware preloaded. However, it is worth checking
that the firmware versions of all chiller stages match, as
incompatible firmware can seem to work during initial
setup but then cause networking problems later.

To view the firmware version of a stage:
1. Press the Program button. See “LCD Buttons” on page 5.

2. Scroll up or down to Technician, and then press Enter.
If prompted for a password, enter 3156.

3. Select Information.

The Information screen is displayed.

4. Scroll down to view version information.

5. Repeat for each stage.
Verify that all stages have the same version number. In
the unlikely event that there is a difference between
stages, the PCB firmware must be updated by a
Dometic-approved technician.

5.5 Networking
When setting up the stages for networking, ensure that
the chillers are not connected via Modbus connections.
Stage 1 requires minimal changes, so start with stage 2,
leaving stage 1 until last.
To set up networking, follow these steps:
1. Power off all stages except stage 2.
2. Press the Program button. See “LCD Buttons” on page 5.
3. Go to Technician.

4. Scroll down to Service settings, then press Enter.

5. For Service Password, enter 3156.

6. Go to Stage Address.

7. Press Enter, then change address to 2 for chiller 2, 3
for chiller 3, and so forth.

8. Press the Scroll Down button to display the next
screen and change the number of stages. Press Enter
until the cursor is on Num of Stages, then change
from 1 to the correct number of stages for the current
system.

9. Repeat steps 2-8 for additional stages.
10. For stage 1, only perform step 8 to change the total
number of stages.

5.6 Configuring Display Addresses
1. Display the configuration screen:
a. PGD1: Press and hold the Up, Enter, and Down
buttons simultaneously for 6 seconds.
b. PLDPRO: Press and hold the Up, Down, and
Program Mode buttons simultaneously for 6
seconds.
To locate buttons, see “LCD Buttons” on page 5.
2. Press Enter to access the Display address setting, and
then scroll up or down to reach the address of the
display per stage:
a. Stage 1: 16
b. Stage 2: 17
c. Stage 3: 18
d. Stage 4: 19
e. Stage 5: 20
f. Stage 6: 21

The message “Display address has been changed”
appears, and then the display goes blank.
3. Repeat the three-button push from step 1 to enter the
configuration.
4. Press Enter three times or until you reach the next
screen.
5. Press Enter to go to the next screen.

6. Follow these steps to select the address for Trm1 & 2
and select if it is private or shared:
a. Press enter once to enter the address of Trm1, and
then scroll up or down to select the appropriate
address (for addresses, see step 2).
b. Press Enter.
–– The cursor under Priv/Shared begins flashing.
–– Scroll up or down to select Pr, then press Enter.
The cursor is next to Trm2.
–– Scroll up or down to select 32, then press Enter.
–– Scroll up or down to select Sh, then press Enter.
–– Press Enter two more times. The cursor is next to Ok?No.
–– Scroll to select Yes, then press Enter.

7. Connect all stages together with the network cable.
The data for all of the stages appears on the main
screen.
8. If using a single common display or remote display, it
must be configured as address 32.

5.7 VARC Standard Wiring Diagram
The following diagrams show the component connections for the standard VARC 48 and VARC 72. The VARC 60 is not shown.

6 Operation

The VARC provides many operational features to
conserve energy, improve performance, and provide
system control.

6.1 Operational Modes
The main operational modes determine whether the
VARC generates heat or cooling: Cool mode, Heat
mode, and Electric Heat mode. Pump operation is
coordinated with these modes.
The VARC also has Econo mode and a Maintenance
mode for troubleshooting.
The operational modes can also be selected using the
digital inputs if wired to the control board. These inputs
allow you to select Econo mode if enabled for either
cool or heat mode. Cool and Reverse cycle Heat mode
can be selected by using the digital input controls. This
allows the system to be switched between modes by
using a common switch or controlled through some
other automated system. These inputs do not support
Electric heat operation.

6.1.1 Cooling and Heating
The VARC supports a Cool mode and two heating
modes: Heat (reverse cycle heating) and Electric Heat.
Cool
When Cool is selected on the touch screen or the
LCD buttons, the VARC starts cooling according to the
temperature setpoint. The pumps operate as described
in “Pump Operation” on page 20.
Cool mode activity is as follows:
• If the return water/supply water temperature is
above the cooling setpoint and the staging delay has
elapsed, the board energizes the compressor relay.
• The compressor continues to run until the cooling
setpoint has been reached or an alarm condition
exists.

• A stage has a minimum run time of 60 seconds before
it can be turned off and a minimum off time of 10
seconds before it can be re-enabled. This minimum
on time is required to ensure that the system is not
cycling on and off and thereby not allowing the
compressor to properly warm-up. This ensures
proper oil lubrication of the system.
• If the system calls for a stage to be toggled on or off,
the next available stage that meets the staging criteria
is used.
• Load shedding occurs in multi-stage operation when
approaching the chilled water setpoint.
Compressor rotation is active during run mode:
• The compressor with the lowest running hours is
enabled first, and the compressor with the highest
running hours is disabled first.
• After chilled water and sea water flows are stable for
10 seconds (default), the first stage is enabled, and
the compressor starts.
• The first stage continues to run up to 100 percent
speed before enabling the next stage.
• If the PID loop requires demand, then the next stage
is enabled with a startup delay of three minutes
before running up to required speed.
Heat (Reverse Cycle Heating)
When Heat is selected on the touch screen or the LCD
buttons, the VARC starts heating according to the
temperature setpoint. The pumps operate as described
in “Pump Operation” on page 20.
Heat mode activity is as follows:
• There is a 45-second delay after the compressor
ramps up before it is energized.
• The reversing valve relay is energized to operate the
VARC in Reverse Cycle Heat mode.
• If the return/supply water temperature is below the
programmed heating setpoint and the staging delay
has elapsed, the VARC energizes the compressor
relay.
• The compressor continues to run and the reversing
valve remains energized until the heating setpoint has
been reached or an alarm condition exists.

• If setpoint is reached, the compressor reduces its
speed to maintain the water temperature. Once it has
reached temperature and a hysteresis of one degree,
the compressor turns off and the reversing valve turns
off immediately.
• A stage has a minimum run time of 60 seconds before
it can be turned off and a minimum off time of 10
seconds before it can be re-enabled. If the system calls
for a stage to be toggled on or off, the next available
stage that meets the staging criteria is used.
Compressor rotation is active during run mode:
• The compressor with the lowest running hours
is enabled first and compressor with the highest
running hours is disabled first.
• Enable Reverse Cycle Heat only for the system.
• After chilled water and sea water flows are stable for
10 seconds (default), the first stage is enabled and the
compressor starts.
• The first stage continues to run up to 100 percent
speed before enabling the next stage.
• If the PID loop requires demand, the next stage is
enabled with a startup delay of three minutes before
running up to the required speed.
Electric Heat (Optional Heater Barrel)
When Electric Heat is selected on the touch screen or
LCD buttons, the VARC starts heating according to the
temperature setpoint.
The VARC energizes the heater relay if return/supply
water temperature is below the programmed setpoint
and the staging delay has elapsed in a multi-stage
configuration.
Heater rotation is active during run mode:
• The heater with the lowest running hours is enabled
first and the heater with the highest running hours is
disabled first.
• Enable Electric Heat only for the system.
• After chilled water flow is stable for 10 seconds, the
first stage is enabled and the electric heater starts.
• The first stage continues to run for five minutes before
enabling the next stage.
• If the PID loop requires demand, the next stage is
enabled.

6.1.2 Pump Operation
The pump modes adjust as required by the system
operating mode.

Chilled Water Pump
The chilled water pump relay closes if the system is in
Heat or Cool mode. The pump is enabled five seconds
prior to the first stage being enabled. The pump is on for
continuous operation when system is enabled.

Sea Water Pump
The sea water pump has selectable operating modes
between continuous operation or cycle-with-compressor
operation. The default configuration is to cycle with the
demand.
The sea water pump relay closes five seconds before the
compressor starts in Heat or Cool modes. It opens five
seconds after the last compressor cycle is completed. If
immersion heating is available and used, the sea water
pump is disabled.

6.1.3 Current Power Limiting
The Econo Mode provides control over the capacity of
the system. When the user enables econo mode, the
system is limited by the speed of the compressor.
The default value for econo mode is 65%. Under
setpoints, the user can adjust the Econo Mode value
between 35% and 90%.

6.1.4 Maintenance
Maintenance mode is available for troubleshooting. See
“Maintenance Mode” on page 39.

6.2 Powerup and Startup
The VARC Chiller Controller can be operated as a singlestage
or a multi-stage chiller plant. During initial setup,
you configure the system for the number of stages and
the available options. The VARC System is set for supply
water control, but it can be modified for return water
control, if needed.

6.2.1 Normal Stage Startup
The system has a time delay between the staging up of
the various stages:
1. Stage 1 is initiated and starts its operation.
2. When the PID determines that more capacity is
required, stage 2 is initiated.
3. When the system has maintained the chilled water
loop and the PID has determined that no additional
stage is required or has met capacity demand, it
reduces the speed of the compressors.
4. The compressors then operate at minimal speed to
maintain the chilled water loop. If the speed of the
compressor still exceeds the demand, the stage with
the most run hours is turned off.

6.2.2 Operational Checks
When the VARC is enabled, the system performs prestartup
checks on all chilled water flow switches and HP
switches.
Individual stage faults disable only that stage.

6.2.3 Compressor Startup
The VARC utilizes a BLDC compressor that is capable
of operating at a very high frequency which requires
that the compressor have a ramped startup to establish
proper lubrication so as to not damage the compressor.
This startup has a ramp time and a minimal speed
operation that will last for 100 seconds to allow the
compressor to properly warm up before operating at
maximum speed.
The compressor minimum on time is 60 seconds and
minimum off time is 10 seconds with a minimum time
between starts of 60 seconds. These default parameters
allow the compressor to operate in a safe mode that will
not damage the compressor.

6.3 Operating the Touch Screen
IISome screens contain pop-up screens with
information. To exit a pop-up, simply touch the X to
close the screen.

6.3.1 Basic VARC Operations
From the Chiller Enable screen, you can perform the
basic VARC operations:
• Change setpoints
• Select Cool, Heat, or Electric Heat
• Monitor water temperature and pump status
• Turn the VARC off
To display the Chiller Enable screen, from the Main
screen, tap Chiller Enable. See “Touch Screen” on
page 5.

Figure 10 shows the controls on the Chiller Enable
screen.

6.2 Powerup and Startup

The VARC Chiller Controller can be operated as a single stage or a multi-stage chiller plant. During initial setup,  you configure the system for the number of stages and  the available options. The VARC System is set for supply  water control, but it can be modified for return water  control, if needed.

6.2.1 Normal Stage Startup

The system has a time delay between the staging up of  the various stages:

1. Stage 1 is initiated and starts its operation.

2. When the PID determines that more capacity is  required, stage 2 is initiated.

3. When the system has maintained the chilled water  loop and the PID has determined that no additional  stage is required or has met capacity demand, it  reduces the speed of the compressors.

4. The compressors then operate at minimal speed to  maintain the chilled water loop. If the speed of the  compressor still exceeds the demand, the stage with  the most run hours is turned off.

6.2.2 Operational Checks

When the VARC is enabled, the system performs pre startup checks on all chilled water flow switches and HP  switches.

Individual stage faults disable only that stage.

6.2.3 Compressor Startup

The VARC utilizes a BLDC compressor that is capable  of operating at a very high frequency which requires  that the compressor have a ramped startup to establish  proper lubrication so as to not damage the compressor.  This startup has a ramp time and a minimal speed  operation that will last for 100 seconds to allow the  compressor to properly warm up before operating at maximum speed.

The compressor minimum on time is 60 seconds and  minimum off time is 10 seconds with a minimum time  between starts of 60 seconds. These default parameters  allow the compressor to operate in a safe mode that will  not damage the compressor.

6.3 Operating the Touch Screen

Some screens contain pop-up screens with  information. To exit a pop-up, simply touch the X to  close the screen.

6.3.1 Basic VARC Operations

From the Chiller Enable screen, you can perform the  basic VARC operations:

• Change setpoints

• Select Cool, Heat, or Electric Heat

• Monitor water temperature and pump status

• Turn the VARC off

To display the Chiller Enable screen, from the Main  screen, tap Chiller Enable. See “Touch Screen” on  page 5.

https://manual-hub.com/

Figure 10 shows the controls on the Chiller Enable
screen.

q Home y Setpoints
w Power Button u Chilled Water Pump
e Cool Button i Sea Water Pump
r Heat Button o Econo Mode Button
t Electric Heat Button
• Home: Displays the Main screen.
• Power Button: Turns the VARC off. When the VARC
is in a run state, this button is green.
• Cool Button: Lights up with the word COOL when
the VARC is cooling. Tapping this button puts the
VARC into cool mode.
• Heat Button: Lights up with the word HEAT when
the VARC is heating. Tapping this button puts the
VARC into heat mode.
• Electric Heat Button: Lights up with the words
ELECTRIC HEAT when electric heat is enabled.
Tapping this button puts the VARC into Electric Heat
mode. This button is visible only if the electric heat
option is installed.
• Setpoints: Displays the current setpoints for cooling
and heating. Tapping the numbers changes the
setpoints.

• Chilled Water Pump and Sea Water Pump:
Tapping this area takes you to the Pump Status
screen.
• Econo Mode Button: Tapping this button displays
the Econo Mode screen, which allows you to select
Normal or Econo Mode.

6.3.2 Selecting Econo Mode
1. From the Main screen, tap Chiller Enable. See “Touch
Screen” on page 5.
2. In the top-left corner of the Chiller Enable screen,
click the Econo Mode button.
The Econo Mode screen appears.

3. Select the desired mode from the Compressor
Current Mode menu.
4. Select the Eco Mode Setpoint value to change the
value of the econo mode.
5. To return to the Chiller Enable screen, in the top-left
corner, tap the left-arrow button.

6.3.3 Viewing Chiller Status for Each  Stage

The Chiller Summary screen provides chiller status for all  stages. It also indicates if a stage is in Alarm Retry mode.

1. To display the Chiller Summary screen, from the Main  screen, tap Chiller Summary. See “Touch Screen” on  page 5.

2. To display a stage, tap its VARC number. 12 Chiller Summary

6.3.4 Monitoring Refrigerant and Chilled  Water Circuits

The Chiller Stage screen provides a graphic  representation of the refrigerant and chilled water  circuits.

To display the Chiller Stage screen, from the Main screen,  tap Chiller Stage. See “Touch Screen” on page 5.

13 Chiller Stage Screen

IDepending on installed options, different icons  appear as hotspots for navigation to open another  window. When the system is in run mode, additional icons appear to indicate cooling and heating.

Using the Electronic Expansion Valve (EEV), you can  monitor the following parameters:

a. Valve position

b. Suction pressure and temperature

c. Superheat setpoint and actual value

To view EEV parameters, on the Chiller Stage Screen,  tap the Expansion Valve icon.

14 Expansion Valve Screen

6.3.5 Viewing and Downloading  Performance Data

The Trends screen provides graphical representation of  the VARC performance data.

1. To display the Trends screen, from the Main screen,  tap Trends. See “Touch Screen” on page 5.

2. To change the time frame, select a time from the  menu. The default is one month.

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Operation VARC Chiller Controls

15 Chiller Trends Screen

3. To download performance data, insert a USB drive  into the USB port on the VARC, and then tap the USB  button.

IIf you do not put the USB drive in first, you get the  message shown in Figure “16 USB Message” on  page 24.

16 USB Message

6.3.6 Viewing Active Alarms and  Downloading Alarm History

The Alarms screen shows all active alarms and allows you  to view the alarm history.

1. To display the Alarm screen, from the Main screen,  tap Alarms. See “Touch Screen” on page 5.

2. To reset alarms, press the RESET ALARMS button.  3. To display the alarm history, tap the History button.

17 Active Alarm Screen

4. To change the time frame, select a time from the menu.  18 Alarm History Screen

5. To download alarm history, insert a USB drive into the  USB port on the VARC, then tap the USB button.

19 Download Alarm History

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VARC Chiller Controls Operation

6.3.7 Enabling Remote Control for Third Party Support

The Remote Support screen allows you to set up the  VARC for control by third- party technical support.

1. To display the Remote Support screen, from the Main  screen, tap Remote Support. See “Touch Screen” on  page 5.

2. To enable or disable remote support, tap the Enable  Remote Support button. (Default is enabled.)

20 Enable Remote Support Screen

3. In the MobileVNC Settings dialog box, on the  Control tab, press Start to begin remote login and  press Stop to finish.

21 MobileVNC Settings Dialog Box

4. Use the settings on the Advanced tab to select  configuration options for the remote login.

22 MobileVNC Settings Advanced Tab

6.4 Operating the LCD Screen IThe following LCD instructions refer to the PGD1 display. For the PLDPRO display, use the  corresponding buttons. See “PLDPRO LCD  Display” on page 4.

6.4.1 Understanding the Display Screens

The Main screen allows you to monitor single-stage  operation and additional stages in multi-stage operation.

The Main screen displays the following parameters: a. Mode of operation (Econo or Normal)

b. Chilled water return temperature

c. Chilled water supply temperature

d. Condenser outlet temperature

IThe condenser outlet temperature is the freeze  control indicator for the condensers in heat mode.

Pressing the Scroll Down button moves through the  various parameters displayed on the LCD screen. In a  multi-stage configuration, you can scroll through the  parameters of the additional stages.

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Operation VARC Chiller Controls

The screens following the main screen contain

information for each stage.

1. The first screen displays the CW Supply and CW

Return temperatures, flow switch status (Fl) and high

pressure status.

5. The final screen displays an image of the refrigerant

circuit and showing the valve position.

2. The next screen displays compressor speed and

information to indicate if the system is in a safety

count down. Once this time has elapsed and other

time delays have been met, the VARC starts up.

3. The next screen displays the suction pressure, the  discharge pressure, the superheat value, and the sub cooling value being calculated by the system.

4. The following screens display the drive status. To  access these screens, press Enter:

6.4.2 Adjusting Setpoints

1. Press the Program button. See “LCD Buttons” on  page 5.

2. Go to Setpoints, then enter the user password  (1234).

3. Press Enter once to update the Heating setpoint,  by pressing the Scroll Up or Scroll Down buttons to  change the value. Press Enter again to change the  cooling setpoint.

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VARC Chiller Controls Operation

6.4.3 Enabling Electric Heat

1. Press the Program button. See “LCD Buttons” on  page 5.

2. Scroll down to Technician, then press enter.

3. Scroll down to Service settings, then press Enter.

4. Enter the service password 3156.

5. Scroll down to System Setup, then press enter.

6. Scroll down to Electric Heat, press Enter to select,  and then press the Scroll Up or Scroll Down buttons  to toggle the setting.

7. Press Enter to save.

6.4.4 Setting Time and Date

1. Press the Program button. See “LCD Buttons” on  page 5.

2. Scroll to Clock/Scheduler, then press Enter.

3. Press Enter.

The cursor flashes on the date field: mm/dd/yyyy.

4. Use the Scroll Up and Scroll Down buttons to select  the correct month. Press Enter, then press the Scroll  Up and Scroll Down buttons to select the correct day.

5. Press Enter, then use the Scroll Up and Scroll Down  buttons to select the year.

6. Press Enter.

a. The cursor drops down to the Hour field.

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Operation VARC Chiller Controls

7. Use the Scroll Up and Scroll Down buttons to select  the correct hour, then select the minute.

a. The cursor goes back to the Clock title. Settings  have been saved and you can exit to Main screen.

b. Daylight Savings Time is enabled by default. If  you wish to disable, scroll down from the Clock  screen.

6.4.5 Changing Temperature Display  Units

1. Press the Program button. See “LCD Buttons” on  page 5.

2. Go to Setpoints, then enter the password (3156).

4. After selecting the desired option, press Enter to  return the cursor to the top of the screen.

5. Make this change to all stages so that it correctly  reflects temperature readings on the remote display.

6.4.6 Viewing Alarms for Each Stage

The Main screen indicates alarms by flashing the word  Alarm in the lower- right corner.

IThe PLDPRO display sounds a tone as well as  displaying the word Alarm in the lower-right corner.

The Alarm screen captures a snapshot of the system  parameters at the time of the fault.

The alarm history captures and displays the following  parameters:

a. Compressor speed

b. Chilled water return

c. Chilled water supply

d. Discharge pressure

e. Suction pressure

1. To view the alarm information for more than one  stage, you need to switch boards via the display or  look at the PLDPRO display for that stage.

2. Use the alarm logger to view the alarm history.

3. Scroll down to the Temperature Units screen. Press

Enter to select. Use the Scroll Up and Scroll Down

buttons to toggle between options.

3. To clear an alarm when a fault has been corrected,

press and hold the Alarm button for five seconds to

clear the active alarm.

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VARC Chiller Controls Operation

6.4.7 LCD Screen Menu Maps

The following diagrams show the menu options for each

screen available through the LCD displays.

The Main screen is displayed at powerup. It displays the

essential system information.

IAn asterisk (*) indicates an option that is available

only when activated in the factory settings.

Main Status Screen

CW Supply Temp ##.#°F

Mode Off/Cool/Heat/ El Ht*

CW Return temp ##.#°F

CW Supply temp ##.#°F

Cond. Outlet temp ##.#°F

Mode Off/Cool/Heat/El Ht*

Pumps

CW On/Off

SW On/Off

Chiller Status Normal/Econo  Maint Mode Active

Stage # Auto/Disabled

Varc #1

CW supply temp ##.#°F

CW return temp ##.#°F

Flow status Ok/Alm/Off

High pressure status Ok/Alm/Off

Electric Heat* Ok/Alm/Off

EH FL* Ok/Alm/Off

Compressor speed #.# Hz

Compressor speed #.# rps

Compressor Current #.# A

Suction

Temperature ##.#°F

Pressure ##.# psi

Saturation Temp. ##.#°F

Discharge

Temperature ##.#°F

Pressure ##.# psi

Saturation Temp. ##.#°F

Super heat temp ##.#°F

Subcooling temp ##.#°F

VARC #* (if multistage)

Varc #1 information

23 Main Screen

Varc # 1 Information

Compressor Capacity Regulator  Required Capacity %

Actual Capacity %

Actual Speed rps

Drive Status

Motor Current #.# A

Motor Voltage # Vrms

DC Bus Voltage ### V

Drive Temperature ## °F

Drive Status Stopped/Running  Fault

Flow Diagram

Super Heat ## °F

Compressor ## °F

EEV Open % ## %

EEV Open Stps ### stp

EEV ### psi

Std-by temp ## °F

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Operation VARC Chiller Controls The Program menu provides access to user settings, the Factory screen, and the Technician screen.

Program

Setpoints

Clock/Scheduler  Input/Output  Alarm History  Board Switch  Technician

Factory

Factory

See Figure 27 Technician

Setpoints

Heating Temperature ##.# °F

Cooling Temperature ##.# °F

Electric Heat*

SP ##°F

Stg Up Stg Down

1 SP – #°F 1 SP + #°F

Current Limiting

Mode Normal/Boost/Econo  Econo #.# Amps

Normal #.# Amps

SW Pump Control By Demand/By Unit On  Temperature Units °F/°C

Pressure Units psi/bar

Clock/Scheduler

See Figure 25  Board Switch

Date ##/##/ Hour ##: Day DST Enable/Disable

Analog Input

DST Enable

Transition ###  Start ###  End Unit address: Switch to unit: Alarm History

Alarm# Message

Compressor Speed CW Return CW Supply Discharge Pressure Suction Pressure 24 Program

Input/Output Analog Input  Digital Input

Relay Output  Analog Outputs

Analog Output Output ##.# Vdc

CW Return Input B001 ###  CW Supply Input B002 ###  SW Inlet Input B003 Digital Input

Flow switch DI 3 Open/Close  Electric Heat Fl DI 5 Open/Close  High pressure switch DI 1 Open/Close  Load Shedding Switch DI 4 Open/Close  Cool Mode Switch DI 6 Open/Close  Heat Mode Switch DI 7 Open/Close

Relay Output

SW Pump Relay 1 On/Off

CW Pump Relay 2 On/Off

REV Valve Relay 3 On/Off

Electric Heat Rly 4 On/Off

Alarm Relay 7 On/Off

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VARC Chiller Controls Operation The Technician menu requires the technician password (3156).

Commission

Enter contact info

Name Telephone No. ###-###- Update info? Yes/No

Commission date ##:## ##/##/ Commission system? Yes/No

BMS Configuration

BMS Port No. #

Pr otocol ###### (scroll)

Address #

Baud Rate Technician

Information

Commission

Working Hours

BMS Configuration

Service Settings

Manual Management

Pump Control

Service Settings

See Figure 26

Pump Control

Ctrl Pos. Status

CW On/Off On/Off On/Off

Manual Management

Analog Input

Digital Input

Relay Output

Compressor & EEV

Compressor & EEV

Enable manual valve position Yes/No

Manual Valve position # steps

Compressor

Mode Auto/Man.

Manual Speed ###.# rps

Required cap. ##.# %

Actual cap. ##.# %

Actual Speed ###.# rps

25 Program/Technician

Information

Service Contact Phone ###-###-####  Version & Date #.## ##/##/##  BIOS & Date

.## ##/##/

Boot & Date #.## ##/##/ Flash Ram ### Kb

T memory

Cycle/s #### ms

Power Cycle Status

Last Off Time ##/##/## ##:##: Last On Time ##/##/## ##:##: Length Time off

Days: # Hrs: ## Min: EVO no.

FW Version #.#

Service Version #.#

Power+ no.1

Boot release FW release FW checksum MC release Hardware ID Working Hours

Run Hrs

Compressor ### h

Electric Heat* ### h

Chilled Water Pump ### h

Seawater Pump ### h

Analog Input

Man Ctrl Man. Pos. Value

CW Return B001 On/Off ##.# ##.#  CW Supply B002 On/Off ##.# ##.#  SW Inlet B003 On/Off ##.# ##.#

Digital Input

Man C trl Man. Pos. Value

Flow DI 3 On/Off Open/Close Open/Close  El. Heat Fl DI 5 On/Off Open/Close Open/Close  High Press DI 1 On/Off Open/Close Open/Close  Load shed DI 4 On/Off Open/Close Open/Close

Relay Output

Man. C trl Man. Pos. Value

SW Pump Relay 1 On/Off On/Off

On/Off

CW Pump Relay 2 On/Off On/Off

On/Off

Rev valve Relay 3 On/Off On/Off

On/Off

Electric Heat Relay 4 On/Off On/Off

On/Off

Alarm Relay 7 On/Off On/Off On/Off

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Operation VARC Chiller Controls

Control Loops

Superheat Setpoint

Cool Setpoint ##°F  Heat Setpoint ##°F  Thermoregulator

Setpoint SH ##°F  LowSH threshold ##°F  LOP threshold temp ##°F  MOP threshold

°F  Modulatin g Setup

Compressor

Working Hour Set

Set Pt Rst to 0? Run H rs

Compressor #### h Yes/No #### h  Electric Heat* #### h Yes/No #### h  Chilled Water Pump #### h Yes/No #### h  Seawater Pump #### h Yes/No #### h

Probe Adjustments

Input Offset Value

CW Return B001 ##.# ##.#

Input #.#  Output #.#  Setpoint #.#

Service Settings Working Hour Set  Probe Adjustments

CW supply B002 ##.# ##.#  SW Inlet B003 ##.# ##.#  Probe adjust

K #

.#

Control Loops

S1 offset ##.# barg

Integration Time Reset System

Reset System  Stage Address  Stage Disable  System Setup

S1 probe ##.# barg  S2 offset ##.# °C  S2 probe ##.# °C  S3 offset ##.# barg

Clear Alarm History Yes/No  Default Installation Yes/No

Stage Address

pLAN Board Addressing

S3 probe ##.# barg

S4 offset ##.# °C

S4 probe ##.# °C

System Setup

Current Address #  Change Address to #  Unit Settings

No. of Stages #

Water Loop Control Supply/Return  Electric Heat Yes/No

EH Flow Switch* Yes/No

Varc Type None/Varc48/60/72  Compressor (Scroll if custom)

Stage Disable

Power type

230 V / 16 A

Stage Control Yes/No

Stage # Auto/Disabled

26 Program/Technician/Service Settings

Power set 230 V / 30 A Set Defaults Yes/No

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VARC Chiller Controls Operation The Factory menu requires the factory password, which is available only to authorized Dometic personnel.

I/O Configuration See Figure 32

Factory Settings See Figure 28

Initialization

Factory

Configuration  I/O Configuration  Factory Settings  Initialization

Configuration

Temperature Units °F/°C  Pressure Units psi/bar  Force clock enable Yes/No Clock mode 24h/12h  Disable Buzzer Yes/No  Startup delay ### s  Enable Unit by

Digital Input On/Off  Supervisor On/Off  pLAN network On/Off  Schedule On/Off Unit Control

Custom 1 On/Off

Erase user settings and install global default value Yes/No  Clear all saved data Factory + User Yes/No  Insert New Passwords

 User  Technician (PW1)  Factory (PW2) EVO Configuration

See Figure 29

Power + n1

See Figure 30

27 Program/Factory

Custom 2 On/Off  Custom 3 On/Off  Custom 4 On/Off  Analog Input Filtering

Enable Yes/No  Input 1 ## s  Input 2 ## s  Input 3 ## s  Manual Control Reset

Enable Yes/No  Time # m  PW/Return Delay ### s  Scheduler

Holidays No. ##  Modbus Settings

1st Master

Baudrat e #####  Stop bit 1/2  Parity Mode None/Even/Odd  Evo Configurator

Power+ n 1

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Operation VARC Chiller Controls

In the following diagram, the dotted boxes indicate a breakout of the additional information that is contained below that  menu category.

Factory Settings

Varc Type None/Varc48/  60/72/96

Compressor Scroll to select  Refrigerant R410A

Power type Based on Inverter  Power set Based on Inverter  Set Defaults Yes/No

Control Temp CCW supply/  CCW return

No. of stages #

Electric Heat (EH) Yes/No

Power Cycle Retain Mode/Off  Logo Select appropriate  Background Select appropriate  Flow Switch Yes/No

High Pressure Switch Yes/No

Low Pressure Switch Yes/No

EH Flow Switch* Yes/No

Load Shedding Yes/No

SW Temp Inlet Yes/No

SW Pump settings

Compressor

Econo mode SW Yes/No  Minimum On ## s

Minimum Off ## s

Min Time between Starts ## s

Load Up Time ## s

Frost Protection

Condenser Setpoint ##.#°F

Condenser Band ##.#°F

Compressor Speed ##.# rps  Envelope Zone (Envelope Status)  Control

Direct/Reverse/Both P/PID/P+I

K ##.#

Minimum Maximum DBd ##.#

Out Alarm Setup

Temperature Limits

Control By demand/   By unit on

Set Pt. Off  Band

Retries Set  Dis able

Status

Off Delay ## s

Pump Current Yes/No  Current Select 10/30/50/75 A

CW High ##.#°C ##.#°F #/## m ## s #/## m CW f reeze ##.#°C ##.#°F #/## m ## s

/## m

CW Pump settings

Flow Prove Delay ## s

Delay Retries Set  Disable

Status

Off Delay ## s  Pump Current Yes/No

CW Flow ## s #/## m ## s #/## m El Heat Fl ## s #/## m ## s #/## m

Current Select 10/30/50/75 A  Reversing valve

High Disch  Pressure

s #/## m ## s #/## m

RV delay time ## s

High Press ## s #/## m ## s #/## m

RV toggle time ## s  RV delay ON time ## s

Low Suct  Pressure

s #/## m ## s #/## m

Electric Heat

Stg Up delay ## s

Stg Down delay ## s

Compressor

Alarm Setup

28 Program/Factory/Factory Settings

Low Suction Pressure

Cool Set Point ##.# bar  Heat Set Point ##.# bar  Inverter

Retrys #/## m  Set Disable ## s  Status #/## m  CW Pump Shutdown

Cool Setpoint ##.# °F  Heat Setpoint ##.# °F  CW Alarm Delay ## s

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VARC Chiller Controls Operation

Configuration

Valve Select Type

Main Regulation Select Type

Auxiliary Regulation Select Type

Probe Configuration

Probe S1 Probe S2 Probe S3 Probe S4

Alarm Enable/Disable Enable/Disable Enable/Disable Enable/Disable

Type Select Select Select Select

Minimum #.# barg #.# barg

Maximum #.# barg #.# barg

Alarm Min. #.# barg ## °C #.# barg ## °C

Alarm Max. #.# barg ## °C #.# barg ## °C

Alarm Mngt Use backup S3/valve at fixed

pos/valve forced

closed/no action

valve at fixed

pos/valve forced  closed/no action

Use backup

S3/valve at fixed pos/valve forced  closed/no action

valve at fixed

pos/valve forced  closed/no action

EVO Configuration

Configuration

Regulation

Custom

Custom

Minimum steps Maximum steps Closing steps Nom. Step rate ## Hz

Fast step rate ## Hz

Holding current ## mA

Duty cycle ## %

Opening synchronicity Yes/No

Closing synchronicity Yes/No

29 Program/Factory/Configuration/EVO Configuration

Regulation

Valve opening at start-up ## %  Valve opened in standby ## %  Prepositioning delay ### s  Alarm delay

Low SH ### s  LOP ### s  MOP ### s  Alarm low suction temp

Threshold ## °C  Timeout ### s

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Operation VARC Chiller Controls

Power + n1

Configuration

Regulation

Custom

Regulation

See Figure 31

Configuration

Motor Type Select

Set Defaults Yes/No

Save to Custom Yes/No

Data Comm. Timeout ## s

U.M. speed Hz/rps

Custom

Motor Poles #

Motor Control Mode PM Motor/AC Motor Vector/AC Motor  Motor base freq. ###.# Hz

Motor base vol. ### Vrms

Motor rated current ##.# Arms

Motor power factor Out current maximum #.#%

Speed profile

Frequency # (1-3) ###.# Hz

Acc. # (1-4) ###.# Hz/s

Delay # (1 -3) ### s

Delay execution Always/Single

Force freq. 2 Enabled/Disabled

Deceleration ramp ###.# Hz/s

V/F Boost voltage #.#%

V/F Freq. adjustment #.#%

V/F Volt. Adjustment #.#%

Drive Replacement Do Nothing/Download Parameters 30 Program/Factory/Configuration/Power + n1

Motor Mag. Current #.# A

Stator Resistance # mOhm

Rotor Resistance # mOhm

Stator/Ld inductance #.# mH

Leakage factor #

Lq Inductance #.# mH

Speed Loop Kp ##.# %

Speed Loop Ki ### ms

Magnetizing Time ### ms

Starting Current #.# % #.# A

Freq. for Start Cur #.# %

Crankcase heater Auto/Force Off/Force On  Crankcase current #.# % #.# A

STO alarm mngt Manual Res/Disable/Auto Reset  Phase loss detection Enable

Overload at Power-on Reset/Restored

Enable Manual R/W Yes/No

Address #

Read Value #

Write Value # Yes/No

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VARC Chiller Controls Operation

In the following diagram, the dotted boxes indicate a breakout of the additional information that is contained below that  menu category.

IAn asterisk (*) indicates an option that is available only when activated in the factory settings.

Regulation

Output frequency min #.# Hz

Output frequency max #.# Hz

Skip frequency set #(1-3) #.# Hz

Skip frequency band #(1-3) #.# Hz

Switching frequency # kHz

Switching frequency derating Disabled/Enabled

Speed derating mode Stop mode Ramp/Coast

Reverse Speed Disabled/Enabled

Flying Start Disabled/Enabled

Relay Configuration Select

PTC Alarm Disabled/Enabled

PTC Alarm delay ## s

Compressor Regulator

Start -up pressure differential control

Max pressure diff. admitted #.# bar

Equalization mode Equalztn valve/EEV Pre-Opening Start -up failure control

Pressure diff. min. variation #.# bar

Control period ## s

Restart delay ## s

Max Retry # #

Speed Management

Start -up forced speed ##.# rps

Max speed ##.# rps

Min speed ##.# rps

Deceleration rate #.# rps/s

Acceleration rate #.# rps/s

Switch -off rate #.# rps/s

Envelope Control

Speed reduction rate #.# rps/s

Min speed admitted #.# rps

Out of env. Alarm timeout ## s

Low press. diff. alarm timeout ## s

Discharge Gas Control High Discharge Temp.

Limit ##.# °C

Alarm ##.# °C

Speed Control due to Discharge Gas

Action Distance ##.# °C

Action Pause ## s

Comp. Speed Reduction #.# %

EEV Regulation

Mode Select from EEV Mode List Discharge Temp Probe Comp Time ##.# s Discharge Super Heat Temperature  Setpoint ##.# °C ##.# °C  Offset ##.# °C

.# °C  Hystere sis ##.# °C ##.# °C  Envelope Control – Low ratio management

By EEV closing Yes/No

By compressor speed Yes/No

31 Program/Factory/Configuration/Power + n1 /Regulation

EEV Pre-Opening*

Max. Equalization ## s  EEV opening ##.# %

EEV Mode List

Suction Superheat

Discharge Temperature  Discharge Superheat

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Operation VARC Chiller Controls I/O Configuration

Analog Inputs

Digital Inputs

Relay Outputs

Analog Outputs

Analog Output

Channel # 0-6

Enable Yes/No

Action Direct/Reverse

Minimum ##.# Vdc

Maximum ##.# Vdc

32 Program/Factory/IO Configurations

 Display Address

Display address setting #

I/O Board address #

Terminal config

33 Display Address

Analog Inputs

Enable

CW Return CW Supply SW Inlet

On/Off On/Off On/Off

Channel B001 B002 B003 Normal/High Res. Normal/High Res. Normal/High Res.

Input Type Select/(On/Off) Select/(On/Off) Select/(On/Off) On/Off

Direction Reverse/Direct Reverse/Direct Reverse/Direct Delay Time ## s ## s s

Value Open/Closed Open/Closed Open/Closed Select type

Minimum ##.# ##.# ##.#

Maximum ##.# ##.# ##.#

Offset ##.# ##.# ##.#

Value ##.# ##.# ##.#

Out of Range Alarm

Power Delay # s # s # s

Run Delay # s # s # s

Units Temp/Press/Other Temp/Press/Other Temp/Press/Other

Digital Inputs

Switches Enable Channel Action Delay Status Flow On/Off # Open/Close ### s Open/Close EH Flow* On/Off # Open/Close ### s Open/Close High Press On/Off # Open/Close ### s Open/Close Low Press On/Off # Open/Close ### s Open/Close LoadShed On/Off # Open/Close ### s Open/Close Econo Mode On/Off # Open/Close

s Open/Close

Relay Output

Enable Channel Status

SW Pump Yes/No # On/Off

CW Pump Yes/No # On/Off

Rev Valve Yes/No # On/Off

El Heat* Yes/No # On/Off

Alarm Yes/No # On/Off

Terminal configuration

P: 01 Adr Priv/Shared

Trm1 16/17/18/…

Trm2 32

Trm3 None

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VARC Chiller Controls Maintenance Mode

7 Maintenance Mode

In Maintenance mode you can disable any of the stages  in the system. This allows for ease of troubleshooting  and maintenance on one unit, while maintaining full  functionality for the other stages.

 WARNING: ELECTRICAL SHOCK HAZARD. Maintenance and repair should be performed only by qualified technicians. Failure to obey this  warning could result in death or serious injury.

7.1 Accessing Maintenance Mode  from the LCD Screen

1. In the Main screen, press Enter and scroll up or down  to select OFF, then press Enter to save.

2. To access the Maintenance mode menu, press  Program, scroll to Technician, and then press Enter.

4. Enter the service password: 3156.

5. Scroll to Stage Disable, then press Enter.

6. For Stage Control, change No to Yes, press Enter,  scroll up, and then press Enter.

The screen displays the stages.

3. Scroll to service settings, then press Enter.

7. Press Enter to access each stage, then scroll up or  down to change from Auto to Disabled.

7.2 Accessing Maintenance Mode  from the Touch Screen

1. Tap the touch screen to view the menu buttons,  then tap Chiller Summary. See “Touch Screen” on  page 5.

IThe system must be in off mode to access  maintenance mode.

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Troubleshooting VARC Chiller Controls

2. Tap the wrench icon.

34 Chiller Summary

3. From the Chiller Control menu, select YES to enable  Maintenance mode.

35 Chiller Control Menu

4. To disable a stage, tap the menu to the right of the  stage number and select Disabled.

36 Disable Stage

5. Tap X to exit, then turn on the VARC.

8 Troubleshooting

The following tables describe the VARC alarm  characteristics and corrective actions.

 WARNING: ELECTRICAL SHOCK HAZARD. Failure to obey the following warnings could  result in death or serious injury:

• Exercise extreme care when working around  energized equipment.

• Maintenance and repair should be performed only by  qualified technicians.

8.1 Alarms

In the event of a fault, the system does not generate an  alarm immediately, but instead applies an alarm retry  logic scheme. The system shuts down and attempts  the number of retries that is set on the parameters table  before creating an alarm that needs to be reset manually.

The following table describes the alarm conditions and  corrective actions to be taken.

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VARC Chiller Controls Troubleshooting

Alarm Reset Delay Alarm

Relay System Action Corrective Actions

Alarms Power+ n˚1 None

1:Overcurrent

2:Motor Overload

3:Overvoltage

4:Undervoltage

5:Over Temp

6:Under Temp

7:Overcurrent HW

8:Motor Overtemp

9:Drive Failure

10:CPU Error

11:Param Default

12:DC bus ripple

13:Data Comms Fault

14:Drive thermistor

15:Autotune fault

16:Drive disabled

17:Motor Phase

18:Fan Fault

19:Speed Fault

20:PFC Failure

21:Overvoltage

22:Undervoltage

23:STO Detection

24:Reserved

25:Ground Fault

26:CPU Sync 1

27:CPU Sync 2

28:Drive overload 29:Reserved

Unexpected  inverter stop

Manual

|

Immediate

|

Yes

|

Turns off compressor

---|---|---|---

After three

retries every

30 minutes,

must be reset  manually

|

Immediate

|

Yes

|

Turns off compressor or  heat relay

Manual

|

Immediate

|

Yes

|

Turns off VARC

Manual

|

10 sec

|

Yes

|

Turns off compressor or  heat relay

Manual

|

10 sec

|

Yes

|

Turns off compressor or  heat relay

• Check the load.

• Check the network control  devices and cables.

• Check the input voltage.

• Using a 1000 V  megohmmeter, check the  motor and motor cables for  ground faults.

• Check the input and output  circuits for phase loss detection.

• Check the condition of the  motor and load wiring.

Chilled Water Flow

• Check for proper loop water  flow and make sure the

strainers are not clogged.

• Check for a defective flow switch.

• Bleed air out of the loop water.

• Check the loop water pump.

Chilled Water Return  Sensor Failure

Chilled Water Supply

• Check the sensor for shorts  and opens.

• Compare the temperature  reading with the digital  thermometer.

HighCheck for low water flow due to  restrictions or pump wear.

Chilled Water Supply

LowCheck for low water flow due to  restrictions or pump wear.

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Troubleshooting VARC Chiller Controls

Alarm Reset Delay Alarm

Relay System Action Corrective Actions

Chilled Water Supply  Sensor Failure

Clock Board Fault or  Not Connected

Compressor Start  Failure

Condenser Out

Temperature Sensor  Failure

Electric Heat Run

Manual

|

Immediate

|

Yes

|

Turns off VARC

---|---|---|---

Automatic

|

Immediate

|

Yes

|

Warning signal

After 5 times

in 60 minutes,  must be reset  manually

|

10 sec

|

|

Warning signal

Manual

|

Immediate

|

|

Warning signal

|

|

Yes

|

Turns off heater

Manual

|

60 sec

|

Yes

|

Turns off compressor

Automatic

|

Immediate

|

Yes

|

Warning signal

Automatic

|

Immediate

|

Yes

|

Warning signal

Automatic

|

Immediate

|

Yes

|

Warning signal

Automatic

|

Immediate

|

Yes

|

Warning signal

Automatic

|

Immediate

|

Yes

|

Turns off compressor

Manual

|

Immediate

|

Yes

|

Slows down

compressor

Automatic

|

30 sec

|

|

Warning signal

• Check the sensor for shorts  and opens.

• Compare the temperature  reading with the digital  thermometer.

• Compare the voltage to the  compressor.

• Check the power inverter.

• Check the sensor for shorts  and opens.

• Compare the temperature  reading with the digital  thermometer.

Hours ExceededCheck heater the voltage. Envelope Alarm

EVD Evo High

Evaporation

Temperature (MOP)

EVD Evo Low

Evaporation

Temperature (LOP)

Check the refrigerant charge.

• Check the water flows.

• Check the refrigerant charge.

TemperatureCheck the refrigerant charge. EVD Evo Low Suction

EVD EVO Low

Superheat

EVD Evo Probes fault  or disconnected (S1,  S2, S3, S4)

• Check for proper refrigerant  charge as the system may be  overcharged.

• Check the water for low flow.

• Check the EEV movement  and functionality.

Check the condition of the wiring  and connections.

Frost Active • Low temperature temp switch  tripped.

• Check the water flows.

• Check r the efrigerant charge.

Temperature Check for the proper refrigerant

High Discharge Gas

pressure with the gauge.

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VARC Chiller Controls Troubleshooting

Alarm Reset Delay Alarm

Relay System Action Corrective Actions

High Discharge  Pressure

After 3 retries  every 30 mins,  must be reset  manually

|

Immediate

|

Yes

|

Turns off VARC

---|---|---|---

After 15 retries  every 60 mins,  must be reset  manually

|

|

|

Manual

|

90 sec

|

Yes

|

Turns off VARC

After 3 retries  every 30 mins,  must be reset  Manually

|

60 sec

|

Yes

|

Turns off VARC

Automatic

|

30 sec

|

Yes

|

Turns off compressor

|

|

|

Warning signal

Manual

|

10 sec

|

Yes

|

Warning signal

Manual

|

Immediate

|

Yes

|

Warning signal

• Check for the proper refrigerant pressure with the  gauge. If normal, check for a  defective pressure switch.

• Check that there is proper sea  water and loop water flow.

• Check that water strainers are  not clogged.

• Check that the system is not  overcharged.

Compatible Make sure Power+ is being used. Inverter Model Not

Low Pressure  Differential

• Check the EEV motor.

• Use a gauge to check for  proper the refrigerant pressure.

• Check suction the temperature to verify that the  reversing valve is in proper  position.

Low Suction Pressure

• Use a gauge to check for the  proper refrigerant pressure.

If  normal, check for a defective pressure switch.

• Check for the proper sea water and loop water flow ‘

• Check that the water strainers  are not clogged.

• Check that the system is not undercharged.

Power+ Device Offline

Power+ in Retry Check the power supply.

Sea Water Inlet Low Low temperature due to  geographical climate.

Sea Water Inlet Sensor

Failure

• Check the sensor for shorts  and opens

• Compare the temperature

reading with the digital

thermometer.

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Disposal VARC Chiller Controls

8.2 Envelope Zone Status

Descriptions

Refer to the following table for envelope alarms. The  alarm shows the zone number and the description  provides details.

Zone Name Description

Inside envelope

zone

High compression  ratio

High condensing  pressure

Maximum motor

current

High evaporating  pressure

Low compression  ratio

Low pressure

difference

Low condensing

pressure

Low evaporating

pressure

1 Working point inside limits

2 Low gas density ->  maximum discharge temperature

3 Mechanical limit

4 High gas density->  maximum torque

5 High gas density->  mechanical limit, noise

6 Loss of contact between  spirals, vibrations

7 Loss of lubrication

8 Low oil temperature ->  high viscosity -> poor  lubrication

9 Low gas density -> low  motor cooling

9 Disposal

M Place the packaging material in the appropriate

recycling waste bins, whenever possible. Consult  a local recycling center or specialist dealer for  details about how to dispose of the product in accordance with all applicable national and local  regulations.

10 Warranty Information

LIMITED WARRANTY AVAILABLE AT

WWW.DOMETIC.COM/WARRANTY.

IF YOU HAVE QUESTIONS, OR TO OBTAIN A COPY  OF THE LIMITED WARRANTY FREE OF CHARGE,  CONTACT:

DOMETIC CORPORATION

MARINE CUSTOMER SUPPORT CENTER 2000 NORTH ANDREWS AVENUE

POMPANO BEACH, FLORIDA, USA 33069 1-800-542-2477

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VARC Chiller Controls

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VARC Chiller Controls

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VARC Chiller Controls

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Mobile living made easy.

dometic.com

YOUR LOCAL DEALER

dometic.com/dealer

YOUR LOCAL SUPPORT

dometic.com/contact

YOUR LOCAL SALES OFFICE

dometic.com/sales-offices

A complete list of Dometic companies, which comprise the Dometic Group, can be found in the public filings of: DOMETIC GROUP AB Hemvärnsgatan 15 SE-17154 Solna Sweden

https://manual-hub.com/

References

• Manual-Hub.com - Free PDF manuals!
• P65Warnings.ca.gov

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