Hitachi RAS-(3-6)HVRNM2E Service Manual page 321

8 Troubleshooting
• Checking procedure for the compressor
CHECK LIST ON COMPRESSOR
Client:
Serie No.
No. Check item
1 Is THM9 correctly connected?
THM9: Discharge Gas Thermistor
2 Is thermistor THM9
disconnected?
3 Is current sensor faulty?
4 Is current sensing part on PCB2
faulty?
5 Is the direction of current sensor
CTU, CTV) reverse?
6 Are power source wires, U and
V inserted correctly into current
sensor? .
7 Is exp. valve (MV1) correctly
connected?
8 Is exp. valve coil (MV1) correctly
connected?
9 Are the refrigeration cycle and
electrical wiring system incorrectly
connected?
10 Is opening of exp. valve
completely closed (locked)?
11 Is opening of exp. valve fully
opened locked)?
12
Are the contacts for comp.
magnetic switch CMC1 faulty?
13
Is there any voltage abnormality
among L1-L2, L2-L3 and L3-L1?
14 Is the comp. oil acidified during
compressor motor burning?
Additional Information for "CHECK LIST ON COMPRESSOR"
Check item
1 & 2 The liquid refrigerant return volume to the compressor is controlled by the discharge gas temperature Td when com-
pressor is operating. If Td thermistor is disconnected, the liquid refrigerant return volume will become small by detect-
ing the temperature even if the actual discharge gas temperature is high. Therefore, this abnormal overheating by
detecting the temperature operation will result in insulation failure of the motor winding.
311
SMGB0064 rev.0 - 08/2011
Model:
Production Date:
Check method
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
1. Check to ensure that thermistor on the top of
comp. is correctly mounted by viewing?
2. Check to ensure that actually measured temp. is
the same as the indication during check mode.
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.
Check the direction => by viewing.
Check to ensure that wires are correctly inserted
Check to ensure that MV1 to CN5A is correctly
connected
Check to ensure that each coil is correctly mounted on
the valve.
Check to ensure that refrigerant is flowing into indoor
units by operating one refrigerating cycle only from the
outdoor unit.
Check the following by the check mode of outdoor
units.
1. Liquid Pipe Temp. (TL) < Air Intake Temp. (Ti)
during Cooling Operation
2. Liquid Pipe Temp. (TL) > Air Intake Temp. (Ti)
during Heating Operation
Check to ensure that liquid pipe temp. is lower than air
intake temp. of stopping indoor unit when other indoor
units are operating under cooling operation.
Check the surface of each contact (L1, L2
and L3) by viewing.
Check to ensure that voltage imbalance is
smaller than 3%.
Please note that power source voltage must be within
380V or 220V+10%.
Check to ensure that the oil color is not black.
Additional information (mechanism of the compressor failure)
Date:
Checker:
Result Remarks
8