Mcquay Hsa Screw Compressor Service Manual |work| – Authentic

1. Model Identification & Safety

• Model range: HSA (e.g., HSA 126, HSA 211, HSA 252) – single-screw compressors used in air-cooled chillers (ALS, AWS series).
• Safety first: Disconnect all power, recover refrigerant, relieve oil pressure. Use personal protective equipment (PPE).

Section F: Reassembly & Timing

Unlike reciprocating compressors, screw compressors have no valves, but timing is everything. The manual provides:

• Timing Gear Positioning: Marks on timing gears must align within one tooth.
• Rotor Mesh Adjustment: Shims behind bearings to adjust clearance.
• Break-in Procedure: Run at low load for 2 hours, change oil, then gradually increase load.

Chapter 6: Maintenance Checklist – Printable from the Manual

Here is a condensed version of the monthly checklist found in the McQuay HSA service manual appendix: mcquay hsa screw compressor service manual

Monthly Preventive Maintenance for McQuay HSA Compressor Model range : HSA (e

• [ ] Record suction pressure, discharge pressure, oil pressure.
• [ ] Calculate oil pressure differential (Discharge – Oil pressure).
• [ ] Check oil level (between 1/4 and 3/4 of sight glass at full load).
• [ ] Listen for unusual knocking or whining (use a stethoscope on the casing).
• [ ] Measure casing vibration (should be <0.25 inches/sec).
• [ ] Inspect oil filter pressure drop (replace if >10 PSID).
• [ ] Verify slide valve position matches control signal.
• [ ] Check for refrigerant leaks around shaft seal and flange joints.
• [ ] Run oil analysis sample (send for spectrometric analysis).

Quarterly:

• [ ] Megger the motor windings (minimum 100 Mohms).
• [ ] Verify crankcase heater operation.
• [ ] Clean oil return strainer in the separator.

Annually:

• [ ] Change oil and filter (see manual for exact quantity).
• [ ] Replace suction and discharge gaskets.
• [ ] Calibrate pressure transducers and thermistors.

Chapter 7: Future-Proofing – Updating Your McQuay HSA Knowledge

The original HSA compressors are aging (some units are 20+ years old). However, Daikin Applied continues to support them. In 2018, Daikin released Service Bulletin SB-HSA-018, which updates several procedures in the original manual: 3. Recommended Service Tools

• New oil viscosity: Moving from ISO 68 to ISO 46 for low-ambient applications.
• Retrofit bearing kits: Ceramic hybrid bearings for longer life.
• Slide valve o-ring material: Upgraded to HNBR for better chemical resistance.

Recommendation: Subscribe to Daikin’s service email list and check for “Manual Revisions” annually. Do not rely on a 2003 PDF in 2025.

3. Recommended Service Tools

• McQuay service tool (MicroTech II or older panel software).
• Torque wrench (specific bolt torque values, e.g., 50–120 ft-lbs for cover bolts).
• Refrigerant recovery unit (R-134a or R-410A depending on vintage).
• Oil pump for pre-lubrication after overhaul.