SMC Networks HRS012-A-10 Series Service Manual page 122

HRX-MM-N007
Chapter 3 Alarm Indication and Troubleshooting
Check the connection
1.
Check the refrigerant circuit pressure sensor (for high pressure) that is connected to the connector
"CN4", pin numbers 10, 11, and 22 of the main board for the check points shown below:
(1) The connector "CN4" is securely connected.
(2) Pin numbers 10, 11, and 22 of the refrigerant circuit pressure sensor (for high pressure) "PS2"
are securely inserted and there is no defective crimping. Check for the correct connection by
lightly pulling the cable.
Fig. 3.3-75 Check connection of the refrigerant circuit pressure sensor (for high pressure)
Check for an input to the pressure sensor in the refrigerant circuit.
2.
Check that the power is supplied to the refrigerant circuit pressure sensor (high pressure).
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.
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
3. Check the output of the refrigerant circuit pressure sensor.
Find which has a problem, the refrigerant circuit pressure sensor (for high pressure) or the main
board.
Follow the instructions shown below:
(1) Perform checking with the Thermo-Chiller not operating.
(2) 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.
(3) Contact the positive probe to the pin number 11 and contact the negative probe to the pin
number 10 of the "CN4" connector.
(4) Check that the voltage between the pin number 10 and the pin number 11 is in the range shown
below:
<Normal> Between pin numbers 10 and 11: 0.5 to 4.5 VDC +/- 0.2 V
3.3 Troubleshooting
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HRS Series