Daikin 2MXS40H2V1B, Service Manual

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SiBE121123_A Check
Service Diagnosis 210
8.6 Outdoor Electronic Expansion Valve Check
Check No.12 Conduct the followings to check the outdoor electronic expansion valve (EV).
1. Check to see if the EV connector is correctly inserted in the PCB. Match the EV unit number
and the connector number.
2. Turn the power off and on again, and check to see if all the EVs generate a latching sound.
3. If any of the EVs does not generate a latching sound in the above step 2, disconnect that
connector and check the continuity using a tester.
Check the continuity between the pins 1 - 6, 3 - 6, 2 - 5, 4 - 5 (between the pins 1 - 5, 2 - 5,
3 - 5, 4 - 5 for the harness 5P models). If there is no continuity between the pins, the EV coil
is faulty.
4. If no EV generates a latching sound in the above step 2, the outdoor unit PCB is faulty.
5. If the continuity is confirmed in the above step 3, mount a good coil (which generated a
latching sound) in the EV unit that did not generate a latching sound, and check to see if that
EV generates a latching sound.
∗
If a latching sound is generated, the outdoor unit PCB is faulty.
∗
If a latching sound is not generated, the EV unit is faulty.
Note: Please note that the latching sound varies depending on the valve type.
If the system keeps operating with a defective outdoor electronic expansion valve, the following
problem may occur.
Valve opening
position
Possible problem Check method
Open Cooling:
Flowing noise of refrigerant in the
unit which is not in operation
Water leakage at the unit which is
not in operation
Operation half due to anti-icing
function
Reset power supply and conduct cooling operation
unit by unit.
Heating:
Flowing noise of refrigerant in the
unit which is not in operation
The unit does not heat the room.
Close Cooling:
The problem unit does not cool
the room.
Only the problem unit is in
operation, the unit starts pump
down.
(The low pressure of the unit
becomes vacuum.)
Abnormal discharge pipe
temperature
Reset power supply and conduct cooling operation
unit by unit.
Heating:
Refrigerant shortage due to
stagnation of liquid refrigerant
inside the faulty indoor unit
The unit does not heat the room.
Abnormal discharge pipe
temperature
Check the liquid pipe temperature
of no-operation unit.
YES
(R14357)
NO
Is it almost
same as the outdoor
temperature?
The EV is not
defective.
Replace the EV
of the room.
Check the low pressure
(R14358)
YES
NO
Does the
pressure become into
vacuum zone?
Replace the EV
of the room.
The EV is not
defective.