Centrifugal Chillers Warning → Critical Interlock (if temperature continues rising)

York YK Chiller Alarm: High Motor Winding Temperature — Causes & Troubleshooting

Published: 2026-06-22

🔍 Symptoms Checklist

⚠️ Motor winding temperature trending upward over hours/days
⚠️ Alarm at 265F (class F insulation limit)
⚠️ Chiller may derate before tripping
⚠️ Possible: ammonia-like smell from overheated epoxy insulation

🛠️ OEM Replacement Parts

Part Name	OEM Part Number	Est. Price
York Motor Cooling TXV	`YK-TXV-MC`	$800-1,500
York Motor RTD Sensor (Phase A)	`YK-RTD-A`	$150-350
York Liquid Line Filter/Drier	`YK-FD-LL`	$180-400

📋 Interactive Diagnostic Procedure

Click each step to expand detailed diagnostic instructions. Follow in sequence — each step builds on the previous one.

1 Check motor cooling liquid line sight glass

Bubbles in the sight glass = insufficient liquid refrigerant reaching the motor cooling TXV. This is usually a charge issue or a restricted filter-drier. Do not confuse with condenser sight glass — the motor cooling circuit has its own.

2 Verify motor cooling TXV operation

Measure superheat at the TXV sensing bulb. If superheat is >15F, the TXV is underfeeding — the motor is not receiving enough cooling. If superheat is <2F, liquid floodback to the compressor may be occurring.

3 Check motor bearing vibration

Increased mechanical friction from bearing wear raises motor operating temperature. Use vibration analysis on the motor non-drive end. Trending vibration over 3-6 months reveals bearing degradation before it causes a trip.

Frequently Asked Questions

What is the normal motor winding temperature for a York YK?

Normal: 180-220F depending on load and condenser water temperature. Warning zone: 230-250F. Trip: 265F. Consistent operation above 240F should be investigated — it indicates the motor cooling system is not keeping up and will eventually trip or reduce motor insulation life.

🔗 Related Error Codes — Centrifugal Chillers

Other diagnostic guides in the same equipment category. Common failure patterns often share root causes — cross-referencing speeds up diagnosis.

Centrifugal Chillers Critical Interlock

⚡ Fault-Induced Energy Waste Estimator

When HVAC equipment runs with active error codes, it operates inefficiently and wastes electricity. Estimate the monthly cost of delaying repairs. All calculations run locally in your browser.

Unit Power Consumption (kW)

Extra Run Time Due to Fault (Hours/Day)

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References & Industry Standards

ASHRAE 15 — Safety Standard for Refrigeration Systems
ASHRAE 34 — Refrigerant Designation & Safety Classification
AHRI 550/590 — Water-Chilling & Heat Pump Packages
SMACNA — HVAC Duct Construction Standards
Manufacturer Service Manuals — Carrier, Trane, York, Daikin, Lennox

York YK Chiller Alarm: High Motor Winding Temperature — Causes & Troubleshooting

🔍 Symptoms Checklist

🛠️ OEM Replacement Parts

📋 Interactive Diagnostic Procedure

Frequently Asked Questions

🔗 Related Error Codes — Centrifugal Chillers

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⚡ Fault-Induced Energy Waste Estimator

References & Industry Standards