Peerless PF-200 Residential PB Heat User Manual

: June 14, 2024
: Peerless

Table of Contents

OVERVIEW
INSTALLATION
ELECTRICAL – WIRING
OPERATION – ALARM CONTACTS
OPERATION – ANALOG INPUT
OPERATION – MODBUS INTERFACE
CUSTOMMER CUPPORT
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Peerless PF-200 Residential PB Heat

OVERVIEW

The PFA-1 Interface Adapter is designed to allow for electronic interface between the Pure Fire® main control and other electronic devices.

Alarm Output:
In the event of a blocking or locking error, the PFA-1 Interface adapter will provide a contact closure to signal an external device (alarm bell, phone dialer, etc.) of a problem.
Analog Input:
The PFA-1 Interface Adapter will accept an analog input of 0-10VDC. This analog signal can be used to control Setpoint Temperature or Gas Input Rate. This signal is typically provided by a Building Automation system. For Cascade installations, only one PFA-1 Adapter is required per cascade system to control the System Setpoint. If Analog control of Gas Input is required, one Inter Face Adapter is required per boiler.
Modbus Interface:
The PFA-1 Interface Adapter allows external access to boiler status information using MODBUS RTU protocol.
This provides remote access to Temperatures, Operating Status and Error Information as applicable.
One PFA-1 control is required for each boiler to which Modbus communication is desired. In a multiple boiler cascade control configuration, each boiler must be equipped with a PFA-1 Interface Control to allow full communication.
a. Temperatures: Supply, Return, DHW and Vent Temperatures can be monitored. In addition, the System Temperature in a multiple boiler (cascade) system can be accessed.
b. Operating Status: The boiler status can be monitored to determine if the boiler is in Standby, Prep urge, Ignition, Firing, Posture or Alarm conditions. It can also indicate if it is satisfying a central heating (CH) or domestic hot water (DHW) demand.
c. Error Information: If the boiler is in a lockout or blocking error, the interface will allow access to the error code.
The PFA-1 Interface Adapter is designed to fit within the Pure Fire® boiler jacket. This manual will provide suggested mounting locations and wiring diagrams.

INSTALLATION

Figure 1 shows the suggested mounting location for the PFA-1 Interface Adapter on the PF-50, PF-80, PF-110 and PF-140 boilers.
- These boilers require a PFA-1 Harness Adapter Kit (provided) to connect to the boiler.

Figure 1

Figure 2 shows the suggested mounting location for the PFA-1 Interface Adapter on the PF-200, PF-210, PF-300, and PF-399 boilers.
- These boilers come with pre-wired harnesses for connection of the adapter. If Modbus is required, two additional wires (provided with kit) must be connected as shown below.

Figure 2

Attach PFA-1 Adapter to jacket panel using adhesive backed Velcro provided with the kit.

ELECTRICAL – WIRING

Figure 3 shows customer wiring connections for the PFA-1 Interface Board.
PF-200, PF-210, PF-300, and PF-399 boilers are equipped with harnesses that provide power and communication to the Interface Board, and alarm contact output to the boiler terminal strip. Connect alarm to boiler terminal strip.
Analog Input (where used):
a. For the PF-200, PF-210, PF-300, and PF-399, connect the analog input device to terminals #15 (-) and #16 (+) on the boiler terminal strip located behind the remote control display.
b. For the PF-50, PF-80, PF-110, and PF-140 boilers, connect the analog input device to the red wires from the J5 connector of the Interface Adapter.
Be sure that these wires are connected with the proper polarity .

OPERATION – ALARM CONTACTS

Alarm Output:

a. The alarm output is a normally open dry contact. If an error is sensed in one of the attached boilers, the Alarm Output contact closes.
b. This output can be used with either line voltage or 24 volts to power a lamp, buzzer, phone dialer or building management system.

Figure 3: Electrical Wiring

COLOR

ABBREVIATION KEY

—— LOW VOLTAGE SIZE 16/18 AWG TYPE TW, TFFN OR TEW/AWM WIRE

120 VAC VOLTAGE SIZE 16/18 AWG TYPE TW, TFFN OR TEW/AWM WIRE

NOTES:

ON PF200/399, USE CONNECTORS PROVIDED ON BOILER HARNESS IN LIEU OF HARNESSES PROVIDED WITH INTERFACE ADAPTER.
ON PF200/399, TERMINALS ARE PROVIDED BEHIND RC DISPLAY TO CONNECT ALARM AND ANALOG INPUT SOURCE.
ON PF50/140, JOIN PUREFIRE LINK WIRES TO SAME COLOR WIRES BEHIND RC DISPLAY.
FIELD WIRE MODBUS SOURCE DIRECTLY TO INTERFACE ADAPTER ON ALL SIZE BOILERS.

OPERATION – ANALOG INPUT

For external control of setpoint temperature or input rate of a Pure Fire® Boiler, a 2-10 volt dc analog signal is to be applied as shown in Figure 3 to the analog input wires.

NOTICE

If the Analog Input is not connected and there is no connection between the red and red/white Analog Input wire, the default input voltage is 2.5 Vdc. Therefore, the boiler will likely run without an Analog Input signal. In this case, all of the standard limits and safety switches will continue to function properly

Analog Input at Setpoint:
Input voltage below 2 volts dc will disable boiler operation. 2 volts corresponds to a boiler setpoint temperature of 60°F and 10 volts corresponds to a boiler setpoint temperature of 200°F. Input voltage between 2 and 10 volts will result in a boiler setpoint temperature proportional to the difference between the 2 volt temperature and the 10 volt temperature. For example, an input of 6 volts will result in a boiler setpoint temperature of 130°F.
Analog Input of Rate:
Input voltage below 2 volts dc will disable boiler operation. 2 volts corresponds to minimum boiler input which will display as 1% Input on the RC Display (see boiler manual for minimum input ratings). 10 volts corresponds to maximum boiler input, and voltages in between will linearly adjust the input rate.

OPERATION – MODBUS INTERFACE

Modbus Configuration:
The table below summarizes the Modbus configuration details:
Modbus Holding Registers:
Modbus communicates using “words” (the contents of 16 bit holding registers). The PFA-1 Interface Adapter organizes the data in read-only holding registers. Table 2 shows the information that is available for reading and the address of the holding registers. Depending on the type of Modbus software used, the holding register addressing range starts at either 0x0000 or 0x0001. The values of STATE and ERROR_NUMBER can be used to determine whether the boiler control is operating correctly, not communicating or in an error state.

Table 1

Modbus Configuration Specifications

Protocol| Modbus RTU
Default Address| 0x01 (settable with Site Vision)
Supported Commands| • Read Holding Registers (0x03)*

• Write Single Holding Register (0x06)

Table 2

Modbus Holding Registers (Read Only)

Item Index| Parameter Name| Address & Holding Registers| Notes
Word| byte| Range Start 0x0000| Range Start 0x0001
0 High byte| 0| STATE| 0x0000| 0x0001| See Table 3
0 Low byte| 1| STATUS| 0x0000| 0x0001| See Table 4
2 High byte| 2| ERROR_NUMBER| 0x0002| 0x0003| See Table 6A and 6B
2 Low byte| 3| WARNING_NUMBER| 0x0002| 0x0003| See Table 7
4 High byte| 4| FLOW_TEMP*| 0x0004| 0x0005| oC = byte value – 10 oF = o C x 9 + 32 5
4 Low byte| 5| RETURN_TEMP| 0x0004| 0x0005
6 High byte| 6| DHW_TEMP| 0x0006| 0x0007
6 Low byte| 7| FLUE_TEMP| 0x0006| 0x0007
8 High byte| 8| NOT USED| 0x0008| 0x0009
8 Low byte| 9| NOT USED| 0x0008| 0x0009
10 High byte| 10| APPLIANCE_TYPE| 0x000A| 0x000B| —
10 Low byte| 11| CONTROL_CONFIG_BYTE| 0x000A| 0x000B| —
12 High byte| 12| CH_MODE| 0x000C| 0x000D| —
12 Low byte| 13| DHW_MODE| 0x000C| 0x000D| —
14 High byte| 14| CH_SETPOINT| 0x000E| 0x000F| —
14 Low byte| 15| DHW_SETPOINT| 0x000E| 0x000F| —

FLOW_TEMP is the boiler supply (outlet) water temperature.

To read these values, issue a Modbus command to read a holding register. For example, if a command is issued to read 0x0000 the resulting, unsigned word may read, “0x090F”. The high byte for this word is “0x09”. Table 3 shows that this value indicates that the burner is on. The low byte for this word is “0x0F”. This indicates that the boiler is on as a result of the freeze protection algorithm as shown in Table 4.

Table 3

Control State Descriptions

The following example describes how to read the temperature holding registers (byte 4-7 and 14-15). The boiler supply and return temperatures can be read by issuing a Modbus command to read holding register “0x0004”. If the word value returned is “0x1D17”, then we know that the high byte is “0x1D” and the low byte is “0x17”. Converting 1D to decimal, we get 29. Using the formula above to convert to degrees Celsius we get, 4.5°C (40°F). Similarly, the return temperature is found by converting the hexadecimal 17 to decimal 23. Using the formula above, this is equivalent to 1.5°C (35°F).

Table 4

Control State Descriptions

Table 5

Determination of General Control Status

Control Status| STATE

Value

| ERROR_NUMBER

Value

Control is not

Communicating Properly

| 0x00| 0x00
Control is Operating Correctly with No Errors| Not 0x00| 0xFF
Control is Operating

Correctly with Errors

| Not 0x00| Not 0xFF

Table 6A describes the ERROR_NUMBER values for Lockout Errors.
These are errors that require a manual reset to continue boiler operation. Table 6B describes the ERROR_NUMBER values for Blocking Errors. Blocking errors are conditions that allow the boiler to continue operation as soon as the condition is corrected.
Table 7 shows values for the WARNING_NUMBER holding register.
These conditions primarily concern the operation of sensors.
If multiple errors are present, the lowest number error will be communicated.

Table 6A

ERROR_NUMBER (Lockout Errors)

Table 6B

ERROR_NUMBER (Blocking Errors)

Table 7

WARNING_NUMBER

Modbus Holding Registers (Read/Write):
The PFA-1 control has holding registers that allow CH and DHW Setpoints to be written using Modbus commands. Table 8 shows the Modbus Holding Registers for Read/Write Control.
Controlling Main Board Parameters:
a. To change the CH setpoint:

```
* Boiler must be set to CH Mode 0 or 3.  
```
Issue a Modbus Write single holding register command that writes 0x0002 to the R/W control register located at 0x001A to switch the CH setpoint reading to writing.
- Calculate the scaled setpoint as follows:
  (°C+10)x2x256=scaled value
- – Issue a Modbus Write single holding register command
  to rite the scaled temperature setpoint value to the
  0x001E holding register.
  b. To change the DHW setpoint:
- Issue a Modbus Write single holding register command that writes 0x0001 to the R/W control register located at 0x001A to switch the CH setpoint reading to writing.
- Calculate the scaled setpoint as follows:
  (°C+10) x 2 = scaled value
- Issue a Modbus Write single holding register command to write the scaled temperature setpoint value to the 0x001E holding register.

Table 8

Modbus Holding Registers (Read/Write)

Item Index| Parameter Name| Address & Holding Registers| Notes
Word| byte| Range Start 0x0000| Range Start 0x0001
10 High byte| 10| R/W control| 0x001A| 0x001B| (oC + 10) x 2 = byte value (oF – 32) x 5 = oC 9
10 Low byte| 11| R/W control| 0x001A| 0x001B
14 High byte| 14| CH_SETPOINT| 0x001E| 0x001F
14 Low byte| 15| DHW_SETPOINT| 0x001E| 0x001F
NOTICE

If no Modbus command is sensed for more than 4.25 seconds after the Write Command is issued, the control resets and the command must be re-issued to change the setpoint.
NOTICE

Modbus setpoints are maintained in volatile memory. Therefore, if the control must be reset due to an lockout error, a new value for CH and DHW must be written through Modbus. If this is not done, the control will default to the last value saved for each of these parameters.
NOTICE

The Pure Fire® main control resets automatically every 24 hours. This will reset the CH and DHW setpoint values to the last value saved for each of these parameters. A new Modbus command should be issued periodically for each setpoint to be sure that the control is targeting the correct temperature.