Applicable Systems
R-Series
Symptoms
Discharge air temperature from the airend exceeds 115C (239F). The high-temperature switch (HTT) has opened, triggering an immediate shutdown to protect the airend and oil system.
Possible Causes
- Dirty oil cooler fins restricting heat transfer and airflow
- Oil separator element clogged, causing back-pressure and elevated compression temperature
- Thermostatic bypass valve stuck closed, preventing oil flow through the cooler
- Ambient temperature exceeds 46C (115F) or the cooler is installed too close to a wall
Troubleshooting Steps
- Step 1: Check the oil cooler exterior for dust, oil film, or debris accumulation between the fins
Blow out the cooler with low-pressure compressed air from the inside outward, or wash with foaming cleaner - Step 2: Monitor the separator differential pressure via the panel gauge or smart controller
Replace the separator element if differential exceeds 0.8 bar (12 psi) or the runtime exceeds 4000 hours - Step 3: With the compressor running, feel the oil cooler outlet line - it should be warm but not hot
If the outlet line is cold while the inlet is hot, the thermostatic valve is stuck closed and must be replaced - Step 4: Verify minimum clearances around the compressor - 1 m on sides, 1.5 m above, per installation manual
Relocate ventilation ducts or add exhaust fans if ambient temperature is consistently above 40C
How to Reset
Reset: The discharge temperature must drop below 95C (203F) before the HTT resets. Press the Reset button on the controller and wait for the 10-minute restart timer.
Common Replacement Parts
- 2342-4956-00: Oil cooler core, R 37-45 (Aluminum brazed plate, 450x280x65 mm)
- 2342-4957-00: Separator element, R 37-45 (Flanged, 200 mm OD x 450 mm height)
- 2342-4958-00: Thermostatic bypass valve (Opens at 75C, 1-inch NPT)
Frequently Asked Questions
- Q: How long should the separator last?
Under normal conditions, 4000-6000 runtime hours. In high-dust environments or with poor oil quality, life may drop to 2000 hours.
- Q: Can a dirty cooler cause permanent damage?
Yes. Sustained high discharge temperatures degrade the oil, varnish the airend, and can warp the rotors. Clean the cooler at every 1000-hour service.
Source: Ingersoll Rand R-Series Operation and Maintenance Manual, 23425330
Category: Compressor