jwasir
25-05-2008, 07:12 PM
Hi,
I designed a refrigeration systems for a falling film chiller.
It is supposed to maintain 35F water temp for salad processing unit.
Both the systems has similar conditions.
One system is equipped with Bitzer Semi Herm. compressor and is running fine from last ONE year.
Second System has Copeland Scroll compressor, which has been replaced for FOUR times in last ONE year.
Last compressor only ran for 1 month and got seized.
Everytime after the compressor replacement, both the suction and liquid filters are replaced with the oil.
Last time, some acid was found in the system, which has been cleaned by changing the oil 4-5 times.
After changing last comp., oil acid test is found GOOD.
Copeland report says that failure happened due to refrigerant dilution.
System superheat is 18F, subcooling, discharge temp, etc all is within envelop.
Comp is appox 10' higher than falling film evap.
It has continous pump-down cycle and HG by-pass.
Indoor application, room maintained at 70-75F.
Comp. has Crank case heater, which was found to be defective in last compressor.
Can you suggest, what could be the reason????????
Can too much oil cause refrigerant dilution??
Any other paramets, which can be checked/adjusted?
Oil return in the system seems not to be problem.
Evap outlet has U bend for oil return!!
I designed a refrigeration systems for a falling film chiller.
It is supposed to maintain 35F water temp for salad processing unit.
Both the systems has similar conditions.
One system is equipped with Bitzer Semi Herm. compressor and is running fine from last ONE year.
Second System has Copeland Scroll compressor, which has been replaced for FOUR times in last ONE year.
Last compressor only ran for 1 month and got seized.
Everytime after the compressor replacement, both the suction and liquid filters are replaced with the oil.
Last time, some acid was found in the system, which has been cleaned by changing the oil 4-5 times.
After changing last comp., oil acid test is found GOOD.
Copeland report says that failure happened due to refrigerant dilution.
System superheat is 18F, subcooling, discharge temp, etc all is within envelop.
Comp is appox 10' higher than falling film evap.
It has continous pump-down cycle and HG by-pass.
Indoor application, room maintained at 70-75F.
Comp. has Crank case heater, which was found to be defective in last compressor.
Can you suggest, what could be the reason????????
Can too much oil cause refrigerant dilution??
Any other paramets, which can be checked/adjusted?
Oil return in the system seems not to be problem.
Evap outlet has U bend for oil return!!