Hitachi YUTAKI Series - Page 180

Troubleshooting
Service Manual
178
Troubleshooting procedure
SMGB0066 rev.0 - 12/2009
Is High Pressure Sensor
Output character and
Low Pressure Sensor display
value "Ps" proper during
compressorStop?
Yes
Replace PCB
Is the voltage between
VCC12 and GND1 12V on
PCB1?
No
Replace PCB
Yes
No
Replace High Pressure
Sensor
A
Is Securely Connected
PCN´s on PCB1 and High
pressureswitch(63H)?
Wiring Check and Repair
(disconnecting wiring Error)
No
Yes
No
Yes
PulloutconnectorPCN5,
Check continuity of High
Pressure Switch (63H).
IscontinuityOK?
Replace High Pressure
Switch (63H)
Isalarmactivatedjust
aftercompressorrunning?
No
Replace PCB
Yes
Is high pressure switch
(63H)activated?
(Is Pd reached
activatedvalue?
No
Replace High Pressure
Switch (63H)
Yes
Is securely connected
CN202onPCB3,4and
CN15?
CN14 on PCB1
No
Wiring Check and Repair
(Disconnecting,WiringError)
Yes
Is securely connected
CN4 on PCB1 and High
Pressuresensor?
No
Wiring Check and Repair
(Disconnecting,WiringError)
Yes
Are High Pressure and Low
Presure shown in segment
as "Pd" and "Ps" coincident
duringcompressorstop?
Yes
Clogging of air side heat exchanger
No
Check of high pressure
Cycle check
Shortage of Water
Pump reverse rotation
Air mixed
Expansion valve malfunction
Water stain in water side heat exchanger
Clogging of Water Strainer



note
In case that the low pressure is higher than 2.2 MPa, segment shows 2.2 MPa. -
In this case, connect a pressure gauge to high pressure check joint, check the pressure shown in the gauge. -