070.655-IOM (FEB 22)
Page 27
SBTP Rotary Screw Compressor
Maintenance
Troubleshooting the hydraulic system
Problem
Cause
Solution
Slide valve does not
load or unload
Solenoid coils have burned out
Replace
Valve is closed
Open hydraulic service valves
Solenoid spool is stuck or the centering
spring is broken
Replace the spool or spring
There is an electrical issue
Check the LED on the coil. If it is lit, there is
power to the coil. Check the coil
To actuate the solenoid mechanically, insert a
piece of 3/16 in. rod against the armature pin
and push the spool to the opposite end. Push
A side to confirm unload capability. If the valve
works, the problem is electrical.
Slide valve loads but
does not unload
A side solenoid coil has burned out
Replace
Dirt inside the solenoid valve is preventing it
from operating both ways
Clean
There is an electrical issue
Check the LED on the coil. If lit, the valve is
functioning mechanically.
To actuate the solenoid mechanically, insert a
piece of 3/16 in. rod against the armature pin
and push the spool to the opposite end. Push
A side to confirm unload capability. If the valve
works, the problem is electrical.
Slide valve unloads
but does not load
A side solenoid coil has burned out
Replace
Dirt inside the solenoid valve is preventing it
from operating both ways
Clean
There is an electrical issue
Check the LED on the coil. If lit, the valve is
functioning mechanically.
To actuate the solenoid mechanically, insert a
piece of 3/16 in. rod against the armature pin
and push the spool to the opposite end. Push
A side to confirm unload capability. If the valve
works, the problem is electrical.
Slide stop does
not function either
direction
Solenoid coils have burned out
Replace
Solenoid service valves are closed.
Open
There is an mechanical issue
Manually actuate the solenoid. If the slide stop
does not move, this indicates mechanical prob-
lems. Consult Johnson Controls-Frick Service.
Note:
for additional information.
