Pressure Sensor Characteristics; High-Pressure Sensor; Low-Pressure Sensor; Procedures For Trouble - Hitachi SAMURAI Series Service Manual

4 Troubleshooting

Pressure sensor characteristics

4.11 Pressure sensor characteristics

4.11.1 High-pressure sensor

4.11.2 Low-pressure sensor

4.12 Procedures for trouble

The following table shows efficient checking procedures for trouble.
Fault
Interlock circuit for chilled water pump is open
Compressor does not
operate
Electrical protective devices are tripped.
Incorrect wiring connection for compressor power
source
Excessively high discharge pressure
Compressor stops on
high pressure switch
Malfunction of high pressure switch
Excessively high discharge pressure and suction
pressure
High or low voltage, single-phase or phase
imbalance
Compressor stops on
overcurrent relay Loose connection
Faulty compressor motor
Faulty overcurrent relay
128 SMGB0120 rev.0 - 11/2017
4.5
2.5
0.5
0
2.5
4.5
2.5
0.5
(0.3)
(-0.1) 0
1.0
Possible cause
5.0
(Mpa)
(Mpa)
2.0
Check/corrective action
1. C heck the pump contactor. Repair or replace, if
necessary.
2. Check for the faulty pump.
Remove the causes, and reset the "ON" button.
See the following causes.
Interchange two of three terminals R, S and T at the
main power source terminals.
See High discharge pressure
Readjust the setting or replace, if defective.
See High discharge pressure
pressure.
Check the power supply line and contactors.
Repair, if necessary.
Tighten the loose electrical connection or repair, if
necessary.
Check the compressor motor. Repair or replace, if
necessary.
Replace it, if necessary.
and High suction