SMC Networks HRS012-A-10 Series Service Manual page 76

HRX-MM-N007
Chapter 3 Alarm Indication and Troubleshooting
10. Check the pressure sensor in the refrigerant circuit.
Two pressure sensors, one for the high pressure and one for the low pressure, are used for the
refrigerant circuit.
The following instructions are 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.
11. After stopping power supply, check for the same alarm goes off when the 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 when the Thermo-Chiller is restarted.
12. 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 high pressure)>
Contact the positive probe to the pin number 22 and contact the negative probe to the pin number
10 of the "CN4" connector.
<Normal> Pin number 22 - Pin number 10: Voltage should be 5 VDC +/- 1V
<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. 3.3-36 Check of the refrigerant circuit
3.3 Troubleshooting
3-60
pressure sensor input
HRS Series