Mcquay Hsa Screw Compressor Service Manual Jun 2026

OEM-specified synthetic polyolester (POE) or mineral oil (per unit nameplate). Genuine McQuay replacement oil filter kit and O-rings. Vacuum pump and recovery machine. Calibrated digital manifold gauges.

High-precision radial and axial thrust bearings (typically angular contact ball bearings) maintain rotor alignment under heavy discharge pressures.

Remedy: Measure the pressure drop across the filter; replace the filter element if it exceeds limits. Faulty oil charging/solenoid valve.

A solenoid valve opens, allowing high-pressure oil to enter the cylinder. This forces the piston forward, closing the bypass port and increasing compressor capacity. mcquay hsa screw compressor service manual

HSA compressors require specific viscosity (typically ISO VG 68 or 100) and additive packages. Automotive or standard refrigeration oil will cause carbonization at discharge valves. Part number lookup for OEM oil.

Compressor operating backward due to incorrect electrical phasing.

The slide valves change the point at which compression begins, allowing refrigerant to bypass back to suction. This movement is hydraulically driven by internal oil pressure and regulated via modulation solenoid valves controlled by the MicroTech chiller panel. 2. Essential Technical Specifications Calibrated digital manifold gauges

, greasing motor bearings, and checking electrical cabinets for dust and moisture. Operating Limitations

The motor is suction-gas cooled and integrated into the compressor housing, eliminating shaft seal leaks.

If the slide valve fails to move smoothly, disassemble the hydraulic cylinder cap. Check the internal piston seals for wear or tearing. Replace seals using the official McQuay seal kit. Faulty oil charging/solenoid valve

• Take an oil sample for laboratory analysis (check for acid, moisture, and metal wear particles).• Tighten all electrical connections inside the terminal box.• Check the calibration of pressure transducers and temperature sensors.

Check expansion valve operation immediately; ensure the suction gas has sufficient superheat to prevent liquid carryover.

I can provide target tolerances, electrical wiring steps, or targeted troubleshooting paths based on your situation.

Apply the appropriate DC voltage (typically 500V or 1000V DC depending on the motor voltage rating) between each terminal pin and the compressor ground chassis.

Technician replaces the starter and contacts motor rewinder. Problem persists.