HRX-MM-N007
Chapter 3 Alarm Indication and Troubleshooting
3.3 Troubleshooting
HRS Series
3-28
18.
Check the analogue output of the refrigerant circuit pressure sensor (for low
pressure).
Find out if the main board is operating connectly.
Follow the instructions shown below:
(1) Check the "PL: Refrigerant circuit pressure on the low pressure side" value in the "Check
Monitor Menu".
(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 23 and contact the negative probe to the pin
number 12 of the "CN4" connector.
(4) Check that the voltage between the pin number 23 and the pin number 12 is in the same
relationship shown in Fig. 3.3-20. (Accuracy: +/- 5%)
(5) If the voltage is in the same relationship as the graph shows, it means that the main board is
operating correctly.
0.0
0.5
1.0
1.5
2.0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
圧力センサDC電圧出力[V]
P
L
：
冷凍回路低圧圧力[
M
P
a]
Fig. 3.3-19 Check of the refrigerant circuit pressure sensor (for low pressure) output
Fig. 3.3-20: Refrigerant circuit pressure sensor (for low pressure) analogue output
PL
:
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w p
re
s
s
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f
th
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(M
P
a
)
Pressure sensor DC voltage output (V)
