Fault Finding; Quick Guide To Fault Finding With Vc Compressors - Fisher & Paykel RB90S64MKIW Service Manual

840653
9.3

Fault Finding

9.3.1

Quick Guide To Fault Finding With VC Compressors

Turning the product off, then on again, resets the control algorithm and it will always try and start the
compressor after 30 seconds when the power supply is switched back on. This is a reliable way of getting
the electronics to try and start the compressor when fault finding.
Note: Compressor Start-up: In case any anomaly occurs during compressor starting, the control will wait 30
seconds before repeating the start-up. If the compressor doesn't start after 3 trials, the control will wait 5
minutes before repeating the start-up procedure (this condition may be when pressures are not equalised
between suction and discharge sides in the refrigeration system). The 5-minute wait time can be bypassed
by resetting the power, as above.
Checking the Compressor
If the compressor fails to start and makes no attempt to start.
• Place a hand on the compressor immediately after switching the power on to check for any vibrations
from the compressor trying to start.
• If there is no movement at all from the compressor, then disconnect the product from the power supply
and remove the terminal cover from the compressor and check the motor winding resistance.
The resistance between any of the 3 pins on the compressor should be approximately 8.44 ohms. If the
resistance is not this value, then the compressor is faulty.
Sealed System Checks:
The VC compressor will not start if there is a restriction/blockage on the high-pressure side of the
refrigeration circuit, e.g. from oil slugging in the capillary.
If all other components have checked OK but the compressor doesn't operate, there may be a
blockage/restriction in the refrigeration system, or the compressor may be faulty.
Flow test:
• Cut the capillary at the filter drier, blocking off the filter side.
• Check for gas flow from the evaporator side of capillary.
• If the system flow checks OK, then the compressor may be faulty.
• Prior to removing the compressor from the product there is one final check to see if the compressor
operates with no load on it.
• With the compressor connected to the control module but disconnected from the refrigeration system,
turn the product on and check if the compressor starts. Make a note of the result of this test on the
compressor before removing it from the product.
38