Issue:
High oil temperature diagnostic?
Resolution:
RTWA 70-125, RTUA 70-125, RTAA 70-125 TON Chillers:
Entering oil temperature to the compressor exceeded 170 F. Time to trip is given by equation:
- Trip time = (190 - Oil Temp) x 180 F/sec
Check for non-condensibles.
Verify oil temperature sensor is operating correctly.
Verify the female solenoid valve on the respective compressor is energizing. If it does not step load the compressor, high temperature discharge gas will circulate internal to the compressor which will elevate the oil temperature. The female unloader is the greater concern, but checking both by measuring amp draw as the compressor loads up will show if they are working.
When the compressor first starts, it will pull around 40% RLA with the female unloader solenoid de-energized. As soon as the female unloader solenoid energizes and the female unloader pulls in, the amp draw will increase approximately 15% in one jump.
As the male load stepper pulse loads, the amp draw will continue to increase, but in much smaller (1-5%) increments.
If the female unloader does not pull in and the amp draw does not show a distinct increase, it cannot be repaired or replaced. The compressor may need to be replaced. Efforts should be made to try and free up the female stepper if it is stuck by pressurizing the schrader just below the female unloader with discharge pressure.
Check operation of oil cooler, make sure there are no excessive pressure drops from the compressor to the downstream side of the oil filter.
Verify the condenser is not fouled.
RTWA ONLY:
- Check operation of oil cooler, including the TRV to ensure it is opening up. It should open when the oil temperature is between 140 F and 150 F.
- Verify the condenser is not fouled. Condenser approach should be less than 5 F.
Notes:
For chillers manufactured prior to April 2002 that have high oil temperature diagnostics while running unloaded KIT08026 can improve performance. The oil protection software was enhanced to be more aggressive at avoiding this diagnostic.
RTAA 35 and 40 TON circuits ONLY: See RTAA-SVN01B-EN for oil cooler modification if needed. (For High Pressure Ratio Applications, the standard oil cooler in the condenser may not be big enough; adding a plate oil cooler can help in these situations.
Changes:
Other Question/Problem/Cause Statements:
- High oil temperature diagnostic?
- High Oil Temperature?
- High Oil Temp - Cprsr A?
- High Oil Temp - Cprsr B?
- High Oil Temperature on Compressor B?
- High Oil Temperature on Compressor A?
Facts:
- Condenser clean.
- Oil temperature sensor appears to be working; based on oil temperature in the oil separator.
- Water-Cooled Chiller (Pueblo) (RTWA)
- Air-Cooled Chiller (Pueblo) (RTAA 70-125 Ton)
- Compressor Chiller (Pueblo) (RTUA)
Document Identifier: DOC-85119
Document Identifier: 85119
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.