Sumitomo HC-4A2 Zephyr - Troubleshooting System Performance; Helium Pressure Loss and Fan Issues

Troubleshooting
48
Problem
Possible Cause
Corrective Action
Gradual loss of helium gas
pressure.
Gas is leaking from the
compressor.
Leak check the compressor and
repair.
Compressor runs; elapsed
time meter does not run.
Defective elapsed time meter
or motor contactor.
Consult a SCAI Service Center.
Fan runs slow or has stopped Open fuse in fan/circulator
circuit
Check for open fuse. Replace if
open.
Defective transformer in
fan/circulator circuit
Check winding resistance and
for ground fault. If defective,
replace transformer
Defective fan motor Check winding resistance and
for ground fault. If defective,
replace fan.
Check for free rotation when
power is off. If rotation is not
free, replace fan.
Shorted run capacitor Check capacitor resistance. If
defective, replace capacitor.
Open internal motor protector Let fan cool and restart
Fan blade obstruction Remove obstruction
Coolant flow has stopped
(Coolant piping between
compressor motor and air
heat exchanger does not get
warm when compressor is
running).
Open fuse in fan/circulator
circuit
Check for open fuse. Replace if
open.
Defective transformer in
fan/circulator circuit
Check winding resistance and
for ground fault. If defective,
replace transformer
Defective circulator motor Check winding resistance and
for ground fault. If defective,
consult a SCAI Service Center.
Shorted run capacitor Check capacitor resistance. If
defective, replace capacitor.
Circulator bearing failure Consult a SCAI Service Center.