SMC Networks HRS012-A-10 Series Service Manual page 120

HRX-MM-N007
Chapter 3 Alarm Indication and Troubleshooting
Check the connection
1.
Check the circulating fluid pressure sensor (for discharge) that is connected to the connector "CN4",
pin numbers 8, 20, and 21 of the main board for the check points shown below:
(1) The connector "CN4" is securely connected.
(2) Pin numbers 8, 20, and 21 of the circulating fluid pressure sensor (for discharge) "PS1 are
securely inserted and there is no defective crimping. Check for the correct connection by lightly
pulling the cable.
Fig. 3.3-74 Check the connection of the
circulating fluid pressure sensor
Check the input to the circulating fluid pressure sensor.
2.
Check that the power is supplied to the circulating fluid pressure sensor (for discharge).
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 21 and contact the negative probe to the pin number 20
of the "CN4" connector.
<Normal> Pin number 21 - Pin number 20: Voltage should be 24 VDC.
3. Check the output of the circulating fluid pressure sensor.
Find which has a problem, the circulating fluid pressure sensor (for discharge) 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 8 and contact the negative probe to the pin number
20 of the "CN4" connector.
(4) Check that the voltage between the pin number 8 and the pin number 20 is in the range shown
below:
<Normal> Between pin numbers 8 and 20: 1 VDC +/- 0.2 V
3.3 Troubleshooting
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HRS Series