3.5 Expansion valve
3.5.2 Repair procedures
2 Remove the expansion valve coil from the expansion valve body, see
"3.5.2 Repair procedures" [4 77].
3 Slide the expansion valve magnet over the expansion valve body and gently rotate the magnet clockwise/counterclockwise to manually close/open the expansion valve.
INFORMATION
After the check, remove the magnet from the expansion valve body and install the expansion valve coil on the expansion valve body. Make sure that the expansion valve coil is firmly slid onto the expansion valve body.
INFORMATION
It is highly recommended to perform a power reset after checking the valve using a magnet.
Does the expansion valve open? Action
Yes Perform an electrical check of the
expansion valve, see "3.5.1 Checking procedures" [4 73].
No Replace the expansion valve body, see
"3.5.2 Repair procedures" [4 77].
To perform an electrical check of the expansion valve
1 First perform a mechanical check of the expansion valve, see "3.5.1 Checking procedures" [4 73].
2 Disconnect the electrical connector of the expansion valve coil from the appropriate PCB and measure the resistance of all windings (between the pins of each phase (wire) and the common wire) using a multi meter. All measurements MUST be approximately the same.
Name Symbol Location (PCB) Connector Winding
resistance Main
expansion valve
Y1E Main S20 46±4 Ω
INFORMATION
Below is an example of the resistance measurements in which the common wire is connected to pin 6 of the expansion valve coil connector. Connections may differ according to the type of expansion valve.
▪ Connector pin 1‑6,
▪ Connector pin 2‑6,
▪ Connector pin 3‑6,
▪ Connector pin 4‑6.
a
a Connector
3 Check the insulation resistance of the coil by measuring the resistance between the pins of each phase (1, 2, 3, 4) and GND on the unit.
Result: None of the measurements should be short‑circuit.
WARNING
When reconnecting a connector to the PCB, make sure to connect it on the correct location and do NOT apply force, as this may damage the connector or connector pins of the PCB.
Is the measured resistance correct? Action
Yes Perform an operation check of the
expansion valve, see "3.5.1 Checking procedures" [4 73].
No Replace the expansion valve coil,
"3.5.2 Repair procedures" [4 77].
To perform an operation check of the expansion valve
Prerequisite: First perform an electrical check of the expansion valve, see
"3.5.1 Checking procedures" [4 73].
1 Turn ON the power of the unit.
INFORMATION
When power is switched ON, PCB checks all expansion valve coil windings by current check. If winding is short or open, expansion valve error is triggered.
2 Start the unit operation via the user interface.
3 With the unit operating, connect the service monitoring tool to the unit.
4 When the expansion valve is closed according to the service monitoring tool, check the inlet and outlet of the valve with a contact thermometer or use an expansion valve stethoscope to see if refrigerant flows through the expansion valve. Check that the valve is NOT bleeding.
Result: There MUST be NO flow through the expansion valve.
5 When the expansion valve is open according to the service monitoring tool, check the inlet and outlet of the valve with a contact thermometer or use an expansion valve stethoscope to see if refrigerant flows through the expansion valve.
Result: Refrigerant MUST flow through the expansion valve.
6 Wait for the PCB to command the expansion valve to open (when closed) or to close (when open) (pulse output to expansion valve visible on service monitoring tool).
INFORMATION
If the PCB does NOT command the expansion valve to open or close (when it is supposed to), perform a check of the appropriate thermistors and pressure sensors (expansion valves are driven by superheat or subcool value calculated through the thermistors).
7 While in opening or closing sequence each expansion valve winding (Ф1, 2, 3, 4) is supplied with 12 V DC from the PCB. You will need a good multimeter, where its range is set to about 20 V DC, and during opening or closing sequence you may be able to measure the supply voltage for a short time. If you set the multimeter range to Auto, then most likely you may NOT read a value between switching ranges. The best way to check is to feel the movement of the valve by touching, rather than trying to measure the driving voltage.
8 When the expansion valve was commanded to close, check the inlet and outlet of the valve with a contact thermometer or use an expansion valve stethoscope to see if refrigerant flows through the expansion valve. Check that the valve is NOT bleeding.
Result: There MUST be NO flow through the expansion valve.
9 When the expansion valve was commanded to open, check the inlet and outlet of the valve with a contact thermometer or use an expansion valve stethoscope to see if refrigerant flows through the expansion valve.
Result: Refrigerant MUST flow through the expansion valve.
Is the flow through the expansion valve correct?
Action
Yes Component is OK. Return to the
troubleshooting of the specific error and continue with the next step.
No Replace the expansion valve, see
"3.5.2 Repair procedures" [4 77].
Problem solved?
After all checking procedures listed above have been performed:
Is the problem solved? Action
Yes No further actions required.
Is the problem solved? Action
No Return to the troubleshooting of the
specific error and continue with the next procedure.
3.5.2 Repair procedures
To remove the expansion valve coil
Prerequisite: Stop the unit operation via the user interface.
Prerequisite: Turn OFF the respective circuit breaker.
Prerequisite: Remove the required plate work, see "3.14 Plate work" [4 143].
1 If needed, remove any parts or insulation to create more space for the removal.
2 Pull up the expansion valve coil to remove it from the expansion valve body.
INFORMATION
It may be needed to turn the expansion valve coil 1/8 turn counter clockwise to unlock it. Make sure to note the correct orientation (position) of the expansion valve coil before removal.
a b
A
A Class 20~35 unit a Expansion valve coil b Expansion valve coil harness
a b
A
A Class 42~71 unit a Expansion valve coil b Expansion valve coil harness
3 Cut all tie straps that fix the expansion valve coil harness.
4 Disconnect the expansion valve coil connector S20 from the main PCB.
5 Remove the expansion valve coil (and harness) from the unit.
6 To install the expansion valve coil, see "3.5.2 Repair procedures" [4 77].
To remove the expansion valve body
Prerequisite: Recuperate the refrigerant from the refrigerant circuit, see
"4.2.2 Repair procedures" [4 202].
Prerequisite: If needed, remove any parts or insulation to create more space for the removal.
1 Remove the expansion valve coil, see "3.5.2 Repair procedures" [4 77].
2 Remove the putty. Keep for re-use.
a c b
A
a a a
A Class 20~35 unit a Putty
b Expansion valve pipe c Expansion valve body
a c b
A
A Class 42~71 unit a Putty
b Expansion valve pipe c Expansion valve body
3 Using a valve magnet, open the expansion valve.
4 Supply nitrogen to the refrigerant circuit. The nitrogen pressure MUST NOT exceed 0.02 MPa.
5 Wrap a wet rag around the components near the expansion valve pipes. Heat the brazing points of the expansion valve pipes using an oxygen acetylene torch and remove the expansion valve pipes from the refrigerant pipes using pliers.
6 Stop the nitrogen supply when the piping has cooled down.
7 Remove the expansion valve body.
INFORMATION
It is ALSO possible to cut the component pipe(s) using a pipe cutter. Make sure to remove the remaining component pipe end(s) from the refrigerant pipes by heating the brazing point(s) of the component pipe(s) using an oxygen acetylene torch.
8 Install plugs or caps on the open pipe ends of the refrigerant piping to avoid dirt or impurities from entering the piping.
9 To install the expansion valve body, see "3.5.2 Repair procedures" [4 77].
To install the expansion valve body
1 Remove the plugs or caps from the refrigerant piping and make sure they are clean.
2 Remove the expansion valve coil from the spare part expansion valve body.
3 Install the expansion valve body in the correct location and correctly oriented.
Insert the pipe ends in the pipe expansions.
4 Open the expansion valve using a valve magnet.
5 Supply nitrogen to the refrigerant circuit. The nitrogen pressure MUST NOT exceed 0.02 MPa.
6 Wrap a wet rag around the expansion valve body and any other components near the expansion valve and solder the expansion valve pipes to the refrigerant pipes.
CAUTION
Overheating the valve will damage or destroy it.
7 After soldering is done, stop the nitrogen supply after the component has cooled‑down.
a c b
A
a a a
A Class 20~35 unit a Putty
b Expansion valve pipe c Expansion valve body
a c b A
A Class 42~71 unit a Putty
b Expansion valve pipe c Expansion valve body
8 Reinstall the putty.
9 To install the expansion valve coil, see "3.5.2 Repair procedures" [4 77].
10 Perform a pressure test, see "4.2.1 Checking procedures" [4 197].
11 Add refrigerant to the refrigerant circuit, see "4.2.2 Repair procedures" [4 202].
To install the expansion valve coil with clip
1 Install the expansion valve coil on the expansion valve body.
INFORMATION
The expansion valve coil is equipped with a pipe retention clip. Install the pipe retention clip over the pipe to lock the expansion valve coil.
b a
c
a Expansion valve coil b Pipe retention clip
c Pipe
2 Route the expansion valve coil harness towards the appropriate PCB.
3 Connect the expansion valve coil connector to the appropriate PCB.
WARNING
When reconnecting a connector to the PCB, make sure to connect it on the correct location and do NOT apply force, as this may damage the connector or connector pins of the PCB.
4 Fix the expansion valve coil harness using new tie straps.
5 Install the insulation cap on the expansion valve coil (if applicable).
Is the problem solved? Action
Yes No further actions required.
No Return to "3.5.1 Checking
procedures" [4 73] of the expansion valve and continue with the next procedure.