
10 Troubleshooting
Checking procedure for main parts
SMGB0091 rev.2 - 11/2015
280
Checking procedure for the compressor
CHECK LIST ON COMPRESSOR
Client:
Model:
Date:
Serie number:
Production date:
Checker:
Nº
Check item
Check method
Result
Remarks
1
Is THM9 correctly connected?
THM9: Discharge Gas Thermistor
1. Is wire of thermistor correctly connected by
viewing?
2. Check to ensure the 7-segment indication of Td
when comp. is operating.
Td: Temperature of THM9
2
Is thermistor THM9 disconnected?
1. Check to ensure that thermistor on the top of
comp. is correctly mounted by viewing?
2. Check to ensure that actually measured
temperature is the same as the indication during
check mode.
3
Is current sensor faulty?
1. Check to ensure that indication A1 and A2 are 0
during compressor stopping.
2. Check to ensure that indication A1 and A2 are not
0 during compressor running.
4
Is current sensing part on inverter
PCB faulty?
5
Is the direction of current sensor
CTU, CTV) reverse?
Check the direction => by viewing.
6
Are power source wires, U and
V inserted correctly into current
sensor?
Check to ensure that wires are correctly inserted
7
Is expansion valve (MV1) correctly
connected?
Check to ensure that MV1 to CN5A is correctly
connected
8
Is expansion valve coil (MV1)
correctly connected?
Check to ensure that each coil is correctly mounted on
the valve.
9
Are the refrigeration cycle and
electrical wiring system incorrectly
connected?
Check to ensure that refrigerant is flowing into indoor
units by operating one refrigerating cycle only from the
RASC unit.
10
Is opening of expansion valve
completely closed (locked)?
Check the following by the check mode of RASC
units.
1. Liquid pipe temperature (TL) < Air Intake
temperature (Ti) during cooling operation
2. Liquid pipe temperature (TL) > Air Intake
temperature (Ti) during heating operation
11
Is opening of expansion valve fully
opened locked)?
Check to ensure that liquid pipe temperature is lower
than air intake temperature of stopping indoor unit
when other indoor units are operating under cooling
operation.
12
Are the contacts for comp. magnetic
switch CMC1 faulty?
Check the surface of each contact (L1, L2 and L3) by
viewing.
13
Is there any voltage abnormality
among L1-L2, L2-L3 and L3-L1?
Check to ensure that voltage imbalance is smaller
than 3%.
Please note that power source voltage must be within
380V+10%.
14
Is the comp. oil acidified during
compressor motor burning?
Check to ensure that the oil color is not black.