SMC Networks HRS012-A-10 Series Service Manual page 40

HRX-MM-N007
Chapter 3 Alarm Indication and Troubleshooting
<With contamination with the heat exchanger>
"t3: Suction temperature of the compressor" ˂ "t2: Circulating fluid return temperature" -5
e.g. (Normal) t2: 21.5, t3: 23.8, (Abnormal) t2: 21.5, t3: 15.5
11. Check the pressure sensor in the refrigerant circuit.
Two pressure sensors, one for high pressure and the other for low pressure, are used for the
refrigerant circuit. Take the following instructions to check for any abnormality with the pressure
sensors:
(1) Stop the Thermo-Chiller operation.
(2) Check the temperature shown for "Ph: Refrigerant circuit pressure on the high pressure side"
and "PL: Refrigerant circuit pressure on the low pressure side" in the "Check Monitor Menu".
(3) If the pressure value shown by each sensor is +/- 0.1 MPa (Ph = PL +/- 0.1), it means that the
pressure sensors are operating correctly.
12. Check for refrigerant leakage.
Refrigerant leakage reduces the cooling capacity. To check for refrigerant leakage, it is necessary to
make the refrigerant circuit temperature same as the ambient temperature. Remove the facility
water piping, stop the Thermo-Chiller operation, and leave it not operating for 24 hours.
Take the following instructions to check for refrigerant leakage after leaving not operating.
(1) Measure the ambient temperature (room temperature).
(2) Check the pressure shown for "Ph: Refrigerant circuit pressure on the high pressure side" in the
"Check Monitor Menu" of the Thermo-Chiller.
(3) If the measured point is lower than the values shown in the graph in "Fig. 3.3-14: Ambient
temperature and refrigerant circuit pressure", it means there is refrigerant leakage caused.
Fig. 3.3-14 Ambient temperature and refrigerant circuit pressure
13. After stopping power supply, check for the same alarm goes off again when the
chiller is re-started.
After stopping power supply (by tuning off the power supply switch of the Thermo-Chiller), check if
the same alarm goes off again when the Thermo-Chiller is restarted.
3.3 Troubleshooting
3-24
o
Ambient temperature ( C)
o
C
HRS Series