Excessively High Discharge Gas Temperature At The Top Of Compressor - Hitachi RAS-(3-6)HVNC1(E) Service Manual

8 Troubleshooting
08
Alarm code
- The alarm appears during cooling operation when the compressor-top thermistor temperature remains at Tdc1 or
above for 10 minutes, or at Tdc2 or above for 5 seconds.
- The alarm appears during heating operation when the compressor-top thermistor temperature remains at Tdh1 or
above for 10 minutes, or at Tdh2 or above for 5 seconds.
Is the thermistor THM9 on top
of compressor normal?
Is the thermistor THM9 installed
correctly on the compressor?
Is gas leaking?

Limits of temperature
Outdoor capacity
RAS-(2-6)H(V)N(P/C)1(E)
RAS-(8-12)HNP(E)
RAS-(8-12)HNC(E)
239
SMGB0087 rev.0 - 12/2013

Excessively High Discharge Gas Temperature at the Top of Compressor

No
Yes
No
Yes
No
Correctly charge refrigerant
Yes
Correctly charge refrigerant.
Thermistor resistance characteristics
72.3
49.9
35.1
25.1
Temperature (ºC)
Tdc1
115
127
127
Faulty thermistor
Install it correctly
Repair leaks of gas.
18.7
13.4 9.93
7,47 5,76
Tdc2
125
135
140
Compressor-top thermistor
(THM9)
Compressor-top thermistor
(THM9)
Tdh1 Tdh2
115 125
120 135
120 140
8