W HLER MR 400 Manifold Refrigerant Instruction Manual

W HLER MR 400 Manifold Refrigerant

General

Information on the operating instructions
These operating instructions enable you to operate the Wöhler MR 400 fitter’s aid safely. Keep these operating instructions in a safe place. The Wöhler MR 400 may only be used by qualified personnel for the intended purpose. We accept no liability for damage resulting from failure to observe these operating instructions.

Notes in the operating instructions

WARNING!
Indicates instructions that, if not followed, may result in injury or death.

ATTENTION!
Indicates information about dangers that may result in damage to the appliance or objects.

NOTE!
Highlights tips and other useful information.

Intended use

The Wöhler MR 400 is a digital fitter’s aid for maintenance work on refrigeration systems and heat pumps. The device precisely displays the high and low pressure as well as the condensation and evaporation temperature of numerous refrigerants in real-time. Two temperature sensors simultaneously and accurately determine super-heating and subcooling. The Wöhler MR 400 must not be used in potentially explosive atmospheres.

Basic equipment

3 AA batteries 1.5 V
| 2 temperature clamps
| Refrigerant hoses, each with

¼” SAE thread, closable with ball valve

| Transport case

Disposal
Electronic devices must not be disposed of in household waste, but must be disposed of following the applicable environmental regulations. Defective batteries are considered hazardous waste and must be taken to the designated collec-tion points for disposal.

Address

Wöhler Technik GmbH

• Wöhler-Platz 1
• 33181 Bad Wünnenberg
• Tel.: +49 2953 73-100
• E-mail: [email protected]

General warnings

WARNING!

• Danger from pressurized, hot, cold, or toxic refrigerants!
• All work on such systems may only be carried out by qualified specialists.
• Never use the unit in designated potentially explosive areas.
• When working on refrigeration systems with flammable refrigerants, an explosive atmosphere must always be expected near the system.
• Wear safety goggles and protective gloves.
• Secure the unit against falling before pressurizing it, e.g. with the suspension.
• Do not operate the device if the housing or hoses are damaged. This applies in particular if the appliance has been dropped or subjected to unusual mechanical stress.
• Replace the hoses if they have been dropped or subjected to mechanical stress.

ATTENTION!
Escaping refrigerant gases are extremely harmful to the environment, depending on the refrigerant. Observe the applicable environmental regulations.

Specification

Measured values

• Pressure
• Temperature
• Refrigerant

Default setting: bar

Measuring range| -1 up to 55 bar
Accuracy| ± 0.5 % of the full scale value
Resolution| 0.03 bar
Description| Indication
selectable units| °C , °F
Measuring range| -40 °C to 150°C
Accuracy| ± 0,5°C
Resolution| 0,1°C
Indication
88 refrigerants selectable in the unit

R113 R114 R115 R116 R12 R123 R1233ZD R1234ZE R1234YF R124 R125 R13 R134A R14 R141b R142b R143A R152A R170 R22 R23 R236FA R245FA R290 R32 R401A R401b R401C R402A R402b R403b R404A R406A R407A R407b R407C R407d R407F R408A R409A R410A R410b R412A R413A R414A R414b R416A R417A R417C R420A R421A R421b R422A R422b R422C R422d R424A R426A R427A R428A R429A R434A R437A R438A R441A R443A R448A R449A R450A R452A R452b R453A R454A R454b R455A R458A R500 R502 R503 R507A R508A R508b R514A R600 R600A R601A R718 R744

• Connections
• Power supply
• Housing
• Environmental conditions

Structure and functions

Device parts

Opening the valves opens the passages from the high- pressure or low-pressure side to the service connec- tion.

__

NOTE!

The pressure is measured with the valves open and closed.

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·         Open the valve: Turn the knob anticlockwise

·         Close the valve: Turn the rotary knob clockwise.

__

ATTENTION!

Always operate the two valve settings by hand only, never with pliers. Closing the knob too tightly can dam- age the knob or the valve.

6| 3 x hose holder (1/4 ” SAE)

__

__

ATTENTION!

If a refrigerant hose is connected to the unit but not to the system, always use the suspension to protect the hose from contamination.

7| Low-pressure connection (Schrader 1/4 ” SAE) Passage can be closed via valve adjustment.

Centre: e.g. for refrigerant bottles or for vacuum pump

8| High-pressure connection 1/4 ” SAE
9| Service connection 1/4 ” SAE
---|---
| Suspension on the rear of the unit
| The battery compartment on the back of the unit

Key functions

Display indication

measurement**
TL| Measured value| The measured temperature on the low pressure side
TH| Measured value| The measured temperature on the high pressure side
ΔT| Calculated value| TH – TL

(Temp. high-pressure side – Temp. low-pressure side)

EV| Assigned value (re- refrigerant)| Refrigerant evaporating temperature
CO| Assigned value (re- refrigerant)| Refrigerant condensing temperature
SH| Assigned value (re- refrigerant)| Overheating
SC| Assigned value (re- refrigerant)| Hypothermia
VAC| Menu| Vacuum measurement
HH:MM| Timer| HH:MM
HOLD| Menu| Pressure test (pressure drop)
ΔP| | Pc-Pi

(pressure liquefaction – pressure evaporation)

SET| Menu| Settings
oFF| | Automatic switch-off is deactivated
oN| | Automatic switch-off is activated
►| | Pressure test stopped
▀| | Pressure test in progress

Device settings

Fig. 17: Display unit settings

| ·         To enter or exit the settings menu, press and hold the Mode button.

It does not matter which menu you are in. SET appears at the top centre of the display.

NOTE!

If no button is pressed for 10 seconds in the settings menu, the unit automatically switches back to the previous menu.

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Converting the units

Temperature units

• In the settings menu, briefly press one of the arrow keys to switch between the units °C and °F
• To save the setting and exit the settings menu, press and hold the Mode button.

Pressure units

• To access the pressure units, briefly press the Mode button in the settings menu.
• Briefly press one of the arrow keys to switch between the units kPa, mPa, bar, psi and kg/m .2
• To save the setting and exit the settings menu, press and hold the Mode button.

Automatic switch off

• In the settings menu, briefly press the Mode button twice to enter the “Automatic switch-off” settings menu. Here you have the option of deactivating or activat-ing the automatic switch-off after 5, 10, 15 ,30 or 60 minutes. The default setting is 15 minutes.
• Press one of the arrow keys to switch between the different options.

Deactivating the temperature compensation
The Wöhler MR 400 performs the pressure test temperature compensation. If required, the temperature compensation can be deactivated as follows:

• In the settings menu, briefly press the Mode button three times to enter the “Temperaturecompensation” settings menu.
• Press one of the arrow keys to deactivate(Hold OFF) or activate (Hold ON) the automatic switch-off.
• The default setting is 15 minutes.
• Press one of the arrow keys to switch between the different options.

Preparation for measurement

Connection of the tem-perature clamps
Fold back the covers on the top of the unit and insert the temperature plugs into the corresponding sockets.

Pressure zeroing

• Switch on the unit. After 4 s, the measuring display appears in the display.
• Press and hold the pressure zeroing button to zero the pressure sensor. Make sure that no additional pressure is applied to the port during pressure zeroing so that only the ambient pressure acts on the sensor.

NOTE!
It is recommended to perform a pressure zeroing before each measurement.

Hose connections

ATTENTION!
Before each measurement, check that the refrigerant hoses are intact. Do not use any tools to connect the hoses. Screw the hoses only hand-tight.

• Close the valves on the meter with the aid of the rotary knobs, cf. Fig. 1, part 5.ATTENTION!

During all work on the system, ensure that the valves on the appliance are opened and closed in the correct sequence. This will prevent refrigerant from escaping.

• Connect the blue refrigerant hose to the low-pressure side, the red refrigerant hose to the pressure side, and the yellow service hose to the center connection.

Select refrigerant

• Press the arrow keys to select the refrigerant of the system to be tested.

NOTE!
The refrigerant can only be selected in the saturation temperature submenu, which appears immediately after switching on.

Measurement menus

Measuring menu PT: Pressure-temperature

Submenu: Saturation temperature (Ev and Co)
After switching on, the unit always displays the saturation temperature submenu. The display shows

Line 1
Temperature low-pressure side Refrigerant (selectable here) Temperature high- pressure side

Line 2
Evaporating temperature Ev Condensing temperature Co

Line 3
Pressure low-pressure side Pressure high-pressure side

Submenu: Superheat-ing and subcooling (SH and SC)

• In the “Saturation temperature” submenu, press the Mode button to enter the “Superheat and subcooling” submenu: The display shows

Line 1
Temperature low-pressure side Refrigerant Temperature high-pressure side

Line 2
Overheating SH Hypothermia SC

Line 3
Pressure low-pressure side Pressure high-pressure side

Submenu: Temperature difference (Δ T)
In the submenu “Superheat/Subcooling”, press the Mode button to enter the submenu “Tempera-ture difference”. The display shows

Line 1
Temperature low-pressure side Refrigerant Temperature high-pressure side

Line 2

• T = TH – TL

Line 3
Pressure low-pressure side Pressure high-pressure side

Measuring menu VAC: Vacuum

A vacuum pump is required to evacuate the sys-tem.

• Connect the coolant hoses to the system.
• Connect the unit to a vacuum pump via the yellow service hose and the center unit con-nection.

The unit thus connects the vacuum pump to the system.

• In the PT measuring menu, briefly press the mode and arrow keys simultaneously. The unit switches to the vacuum measurement menu. VAC appears at the top left of the display.
• Switch on the vacuum pump to extract air and moisture from the unit.

NOTE!
The Wöhler MR 400 only indicates a negative pressure in the system. If the system pressure is above the ambient pressure, appears as a pressure display – – – – .

The display shows

• Line 1 : Refrigerant
• Line 2 : Timer: elapsed time, since the start of vacuum measurement (hours: minutes)

NOTE!
After calling up the vacuum menu, the timer basically starts counting. The colon between hours and minutes flashes.

Line 3:

• Left: Vacuum share in %
• Right: current negative pressure in the system

NOTE!
The displayed vacuum percentage is not a precise measured value but serves only for estimation.

Pressure test (Hold)
The unit performs a temperature-compensated pressure test. The system pressure and the ambient temperature are measured over a certain period. The pressure drop, i.e. the temperature-compensated differential pressure (start of measurement – pend of measurement), which is determined over the measurement time, provides information about the tightness of the system.

NOTE!
The meter has an internal temperature sensor. If a temperature clamp is connected, the unit uses this value for temperature compensation. The pressure test/pressure drop test is carried out on systems without refrigerant. The line is pressurized with an inert gas. The test pressure is usually 1.1 times the operating pressure specified by the manufacturer.

• Connect the coolant hoses to the pressure connections of the unit and the system under the test.
• Connect the yellow service hose to the center connection of the unit and connect the other end to the container for the inert gas.
• In the vacuum measurement menu, briefly press the mode and arrow keys simultaneously. The unit switches to the measuring menu for pres-sure testing. HOLD appears at the top left of the display.
• To start the pressure test, press the start/stop button.

The display shows a▀ icon next to the HOLD icon and the timer starts counting the minutes.

• Line 1 : Refrigerant
• Line 2 : left: Timer, right: differential pressure
• Line 3 : left: Output pressure, right: currently measured pressure
  • To stop the pressure drop test, press the start/stop button.

The display shows a▀ icon next to the HOLD icon and the timer starts counting the minutes.

• Line 1: Refrigerant
• Line 2: left: Timer =0, right: differential pressure
• Line 3: left: Final pressure

Maintenance

Insert or change batteries

• Switch off the unit.
• Fold up the suspension on the back of the unit.
• Open the battery compartment with a Phillips screwdriver.
• Insert 3 AA Mignon 1.5 V batteries. Observe the correct polarity.

ATTENTION!
Remove the batteries if you are not going to use the unit for a longer period.

Coolant hoses

• Replace the hoses with new ones after mechanical stress or after the meter has fallen.

Cleaning

• Clean the housing with a damp cloth.
• Make sure that the threaded connections are free of grease or other deposits. Clean the connections with a damp cloth if necessary.

Tips and help

or

The temperature value is below the specification

| Connect temperature clamps
Temperature dis- play – OL –| The temperature value is above the specification|

Warranty and service

Warranty
Every Wöhler MR 400 fitter’s aid is tested for all functions and only leaves our factory after a detailed quality check. If used properly, the warranty period on the Wöh-ler MR 400 fitter’s aid is twelve months from the date of sale. Excluded are batteries and damage to the pressure sensor caused by overloading. The warranty does not apply if repairs and modifications have been carried out on the unit by a third party, not authorized by the manufacturer.

Service

SERVICE is very important to us. That is why we are of course also there for you after the warranty period.

• You send the meter to us, we repair it within a few days and send it to you with our parcel service.
• Immediate help is available from our technicians on the phone.

Declaration of conformity

The manufacturer: WÖHLER Technology GmbH Wöhler-Platz 1, D-33181 Bad Wünnenberg explains that the product: Product name: Wöhler MR 400 Fitting aid complies with the essential protection requirements laid down in the Council Directives on the approximation of the laws of the Member States relating to electromagnetic compatibility 2014/30/EU. The following standards were used to assess the product about electromagnetic compatibility:

• EN IEC 61326-1:2021
• EN IEC 61000-3-2:2019 + A1:2021
• EN 61000-3-3:2013 + A1:2019 + A2:2021
• Bad Wünnenberg, 19.02.2024
• Dr. Michael Poeplau, Geschäftsführer/Managing Director

Quick guide

1. Vacuum seal the tubes.

2. Press the power button for 2 s to switch on the unit.

3. Press the arrow keys to select the refrigerant
   NOTE!
   The refrigerant can only be selected in the saturation tempera-ture submenu, which appears immediately after switching on.

4. Connect the high-pressure side and the low-pressure side of the unit to the system under test.

5. Connect the cable of the temperature clamps to the top of the Wöhler MR 400 and clamp the clamps onto the pipes of the system to be tested.

6. Switch on the system under test and monitor the parameters.

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