Frick SGXH-4021 - Troubleshooting the SGC Compressor; SGC Compressor Symptom Resolution; Troubleshooting the Hydraulic System

070.650-IOM (JUL 19)
Page 39
SGC/SGX ROTARY SCREW COMPRESSOR
MAINTENANCE
TROUBLESHOOTING THE SGC COMPRESSOR
Symptom Probable causes and corrections
Slide valve and/or slide
stop can't move
• 4-way hydraulic control valve failed. Repair or replace.
• Slide stop indicator rod stuck. Contact Johnson Controls – FRICK Service for assistance.
• Check both S.V. and S.S. feedback devices for wiring and resistance.
•Compressormustberunningwithsufcientoilpressure.
• Unloader piston stuck. Contact J ohnson Controls – FRICK Service for assistance.
• P iston Seals worn out/damaged. Contact Johnson Controls - FRICK Service for assistance.
Notice
Unless the Service Technician has been certied by Johnson Controls – FRICK to rebuild our compressors, troubleshoot-
ing the compressor is limited to identifying the probable cause. If a mechanical problem is suspected contact Johnson
Controls – FRICK Service. DO NOT ATTEMPT TO DISASSEMBLE COMPRESSOR.
TROUBLESHOOTING THE HYDRAULIC SYSTEM
Symptom Probable causes and corrections
Slide valve can't load or
unload
• Solenoid coils burned out. Replace.
• Valve closed. Open hydraulic service valves.
• Solenoid spool stuck or centering spring broken. Replace.
• Check LED on coil. If lit, there is power to the coil. Check coil.
• Solenoid may be actuated mechanically by inserting a piece of 3/16 in. rod against ar-
maturepinandpushingspooltooppositeend.PushAsidetoconrmunloadcapability.
If valve works, problem is electrical.
Slide valve can load but
can't unload
• A side solenoid coil may be burned out. Replace.
• Dirt inside solenoid valve preventing valve from operating both ways. Clean.
• Check LED on coil. If lit, valve is functioning mechanically. Problem is electrical.
• Solenoid may be actuated mechanically by inserting a piece of 3/16 in. rod against ar-
maturepinandpushingspooltooppositeend.PushAsidetoconrmunloadcapability.
If valve works, problem is electrical.
Slide valve can unload but
can't load
• A side solenoid coil may be burned out. Replace.
• Dirt inside solenoid valve preventing valve from operating both ways. Clean.
• Check LED on coil. If lit, valve is functioning mechanically. Problem is electrical.
• Solenoid may be actuated mechanically by inserting a piece of 3/16 in. rod against ar-
maturepinandpushingspooltooppositeend.PushAsidetoconrmunloadcapability.
If valve works, problem is electrical.
Slide stop can't function
either direction
• Solenoid coils may be burned out. Replace.
• Solenoid service valves may be closed. Open.
• Manually actuate solenoid. If slide stop can't move, this indicates mechanical problems.
Consult Johnson Controls - FRICK Service.