Mcquay Hsa Screw Compressor Service Manual ~upd~

The Ultimate Guide to the McQuay HSA Screw Compressor Service Manual: Maintenance, Troubleshooting, and Best Practices

A. Oil Change

1. Run compressor 20 minutes, then shut down.
2. Pump down or recover refrigerant from the oil sump.
3. Drain oil from bottom drain valve (oil volume: 4–12 liters depending on model).
4. Replace oil filter (access via hex plug on compressor body).
5. Refill with McQuay-approved oil: POE (ISO 68) – e.g., Mobil EAL Arctic 68, ICI Emkarate RL 68H.
6. Evacuate oil separator, then open valves, re-start.

2. Basic components covered in the manual

• Rotors and casing: Twin-screw element, timing gears, bearings.
• Lubrication system: Oil pump, filter, cooler, sight glass, and oil separators.
• Valves and controls: Suction/discharge valves, unloader, oil regulating valve, pressure sensors, and safety switches.
• Drive train: Coupling, motor alignment, and flexible couplings.
• Cooling system: Air or water-cooled oil coolers and heat exchangers.
• Electrical/control panel: Starters, contactors, overloads, control logic.

2. Compressor Components

• Single screw rotor with two gaterotors (star wheels).
• Oil separator (integral high-efficiency type).
• Oil filter (replaceable cartridge inside compressor body).
• Oil level sight glass (critical for operation).
• Slide valve for capacity control (25–100% in steps or continuous).
• Motor stator & rotor (hermetic refrigerant-cooled motor).

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:

Monthly Preventive Maintenance for McQuay HSA Compressor mcquay hsa screw compressor service manual

• [ ] 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.

---

Section C: Maintenance Schedules

• Daily: Check oil level sight glass, suction superheat, discharge temperature.
• Monthly: Analyze oil pressure differential (min 25 PSID).
• Annually: Oil sample analysis, vibration monitoring, check slide valve operation.
• 5,000 Hours: Change oil filters and replace dryer cores.
• 10,000 Hours or 5 Years: Full teardown inspection – replace bearings, thrust washers, and shaft seals.

Section B: Technical Specifications

• Dimensions & Weights: Lifting points are critical.
• Oil Charge: Type (McQuay OEM oil or equivalent polyolester/polyalphaolefin) and quantity (e.g., 12 gallons for HSA 200).
• Refrigerant Charge Guidelines: Maximum operating pressure (typically 250–300 PSI for R-134a).
• Clearance Data: Rotor end clearance (0.002”–0.004”) and radial clearance.

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).