SiUS12-928_A
Check
Service Diagnosis
150
6.1.2 Electronic Expansion Valve Check
Check No.04
Conduct the followings to check the 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 latching sound.
3. If any of the EVs does not generate 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 and 3 - 6, and between the pins 2 - 5 and 4 - 5. If
there is no continuity between the pins, the EV coil is faulty.
4. If no EV generates 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 latching
sound) in the EV unit that did not generate latching sound, and check to see if that EV
generates latching sound.
∗
If latching sound is generated, the outdoor unit PCB is faulty.
∗
If 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 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 halt 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
(R11266)
NO
Is it almost
same as the outdoor
temperature?
The EV is not
defective.
Replace the EV
of the room.
Check the low pressure
(R11267)
YES
NO
Does the
pressure become into
vacuum zone?
Replace the EV
of the room.
The EV is not
defective.
Summary of Contents for SUPER MULTI NX G Series
Page 1: ...SiUS12 928_A Applied Models Inverter Multi Heat Pump G Series J Series...
Page 7: ...SiUS12 928_A Table of Contents vi...
Page 10: ...SiUS12 928_A 1 List of Functions Part 1 List of Functions 1 Functions 3...
Page 11: ...SiUS12 928_A List of Functions 2...
Page 17: ...SiUS12 928_A Specifications 8...
Page 23: ...SiUS12 928_A Specifications Specifications 14...
Page 25: ...SiUS12 928_A Printed Circuit Board Connector Wiring Diagram 16...
Page 37: ...SiUS12 928_A Function and Control 28...
Page 69: ...SiUS12 928_A Control Specification Function and Control 60...
Page 71: ...SiUS12 928_A Operation Manual 62...
Page 73: ...SiUS12 928_A Duct Free System Operation Manual 64 2 Duct Free System 2 1 Remote Controller...
Page 84: ...Duct Free System SiUS12 928_A 75 Operation Manual...
Page 85: ...SiUS12 928_A Duct Free System Operation Manual 76 2 8 TIMER Operation...
Page 86: ...Duct Free System SiUS12 928_A 77 Operation Manual...
Page 87: ...SiUS12 928_A Duct Free System Operation Manual 78 2 9 Note for Multi System...
Page 88: ...Duct Free System SiUS12 928_A 79 Operation Manual...
Page 97: ...SiUS12 928_A Slim Duct Built In System Operation Manual 88...
Page 99: ...SiUS12 928_A Service Diagnosis 90...
Page 169: ...SiUS12 928_A Removal Procedure 160...
Page 225: ...SiUS12 928_A Trial Operation and Field Settings 216...
Page 235: ...SiUS12 928_A Appendix 226...