Issue:
Loss of oil compressor stopped.
Resolution:
RTHC only - Can perform oil line accumulator modification to improve oil circuit operation. See attached photo for reference.
- Mechanical: The modification is simply adding a 3/8" Normally Open Solenoid Valve to the 3/8" line leaving the oil accumulator and tee it into the 7/8" line leaving the optic sensor.
- Electrical: Wire the coil of the added valve in parallel with the coil of the master oil solenoid valve.
Possible causes:
Low differential pressure
Oil charge
EXV
LLS
Master oil solenoid valve
Restriction
Oil separator
Optic sensor
Low evaporator water flow (Causes carryover which drains the oil sump)
RTHD and RTHC
This diagnostic is generated when the optical eye sensor is reading dry at startup meaning the sensor is not detecting oil in the sump. It typically reads as "wet" meaning there is oil in the oil sump. Need to determine why there is no oil being sensed.
- Check the integrity of the gas pump circuit. This can be done by monitoring the discharge superheat in TrendView (RTHD) looking for the superheat to follow a "shark fin" or sawtooth wave form. The amplitude should be approximately 3F peak to peak. The waveform should repeat itself during steady state operation with no abnormalities from the pattern.
- This problem could also be caused if the refrigerant/oil migrates from the oil sump causing the oil loss sensor to read dry.
- Also, oil over charge; plugged filters (Hot and/or Cold); or oil under charge.
- Check the operation of the master oil solenoid
- Check the orientation of the master oil solenoid valve (proper flow direction)
- Check the operation of the optical eye sensor. (Refer to bulletin below)
Whenever the chiller sees an unexpected shutdown, the compressor does not have a chance to unload and there are larger differential pressures that need to equalize in the system. These larger differential pressures, if frequent, may wash out the oil sump. A similar condition can occur if the chiller is shut off for a longer period of time.
It is best to not allow the chiller to be shut down by a chilled water pump losing flow if possible. Also, if a chiller is going to be shut down for an extended period of time, it is wise to close the vent line valve between the condenser and the oil sump to minimize migration.
Notes:
Refer to RTHC-SVD01B-EN for procedures to check proper operation of gas pump and optical eye sensor.
TECHTV:
Rotary Chillers: Troubleshooting Optical Sensor
Changes:
Other Question/Problem/Cause Statements:
- Loss of oil compressor stopped.
- Chiller will not start, starter will not operate.
- Tripped on oil loss compressor stopped.
Facts:
- Water-Cooled Chiller (Pueblo) (RTHC)
- Water-Cooled Chiller (Pueblo) (RTHD)
- There was a history of multiple chilled water flow loss diagnostics.
Document Identifier: DOC-83223
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.