| Problem | Likely Cause (from manual) | Solution | | :--- | :--- | :--- | | High discharge temp | Low suction superheat or oil starvation | Check expansion valve, clean oil strainer | | No capacity control | Slide valve stuck or broken piston ring | Remove actuator, inspect slide valve bore | | Loud rattling noise | Worn rotor bearings or debris in rotors | Immediate teardown – do not restart | | Oil level dropping | Failed oil separator coalescer or leaking shaft seal | Replace separator element, replace shaft seal kit |
: The manual covers the asymmetric slide regulation used for infinitely modulating capacity. mcquay hsa screw compressor service manual
Check for liquid/oil return or high discharge temperature trips. Ensure correct motor cooling valve operation. Frequent Cycling | Problem | Likely Cause (from manual) |
Check for dirt, dust, and moisture in the electrical cabinet monthly. Rotary screw compressor maintenance checklist | Infographic Frequent Cycling Check for dirt, dust, and moisture
: Standard Star-Delta starting reduces electrical inrush current during startup. Diamond Compressors wiring diagrams from the service manual? AI responses may include mistakes. Learn more McQuay PFS Water Cooled Screw Chiller | PDF - Scribd