SMC Networks HRS012-A-10 Series Service Manual page 93

Check the surrounding environment.
1.
Check if the surrounding environment is in the conditions shown below:
(1) Flow rate fluctuates due to a valve and a switching valve in the external piping. (Heat load is
fluctuating.)
(2) Heat that is larger than the cooling capacity is transiently being applied to the Thermo-Chiller.
Check the pressure sensor in the refrigerant circuit.
2.
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.
After stopping power supply, check for the same alarm goes off again when the
3.
chiller is re-started.
After stopping power supply (by tuning off the power supply switch on the Thermo-Chiller), check if
the same alarm goes off again when the Thermo-Chiller is restarted.
4. Check for an input to the pressure sensor in the refrigerant circuit.
Check that the power is supplied to the refrigerant circuit pressure sensor.
Check voltage by contacting the probe of the tester directly to the connector external surface with
the "CN4" connector of the main board being inserted.
<Refrigerant circuit pressure sensor (for low pressure)>
Contact the positive probe to the pin number 24 and contact the negative probe to the pin number
12 of the "CN4" connector.
<Normal> Pin number 24 - Pin number 12: Voltage should be 5 VDC +/- 1V
Fig. 3.3-54 Check of the refrigerant circuit pressure sensor (for low pressure) input
HRS Series
Chapter 3 Alarm Indication and Troubleshooting
HRX-MM-N007
3.3 Troubleshooting
3-77