Evacuating the Compressor
Evacuating the Compressor
Whenever repairs to a compressor allow any appreciable amount of air to enter the unit, the compressor should be evacuated after assembly is completed and before it is ready for operation The proper procedure is as follows:
1. Disconnect a connection in the compressor discharge gauge line between the discharge line stop valve and the compressor.
2. Start the compressor and let it run until the greatest possible vacuum is obtained.
3. Stop the compressor and immediately open the suction stop valve slightly. This will blow refrigerant through the compressor valves and purge the air above the discharge valves through the open gauge line.
4. Close the discharge gauge line and open the discharge line stop valve.
5. Remove all oil from the exterior of the compressor.
6. Test the compressor joints for leakage using the halide leak detector.
Cleaning Suction Strainers
When putting a new unit into operation, you should clean the suction strainers after a few hours of operation. Refrigerants have a solvent action and will loosen any foreign matter in the system. This foreign matter will eventually reach the suction strainers. After a few days of operation, the strainers will need another cleaning. Inspect them frequently during the first few weeks of plant operation and clean as necessary.
The suction strainers are located in the compressor housing or in the suction piping. The procedure for cleaning the strainers is as follows:
1. Pump down the compressor.
2. Remove the strainer and inspect it for foreign matter.
3. Dip the strainer screen in an approved solvent and allow it to dry.
4. Replace the strainer and evacuate the air from the compressor.
5. Test the housing for leaks by wiping up all oil and then using a halide leak detector.
Maintenance Precautions
Sometimes a compressor cannot be pumped down and is damaged to the extent that it has to be opened for repairs. If so, you should first close the suction and discharge valves. Then allow all refrigerant in the compressor to vent to the atmosphere through a gauge line.
When you must remove, replace, or repair internal parts of the compressor, observe the following precautions:
1. Carefully disassemble and remove parts; note the correct relative position so that errors will not be made when you reassemble.
2. Inspect all parts that become accessible.
3. Make certain that all parts and surfaces are free of dirt and moisture.
4. Freely apply clean compressor oil to all bearing and rubbing surfaces of parts being replaced or reinstalled.
5. If the compressor is not equipped with an oil pump, make certain that the oil dipper on the lower connecting rod is in the correct position for dipping oil when the unit is in operation.
6. Position the ends of the piston rings so that alternate joints are on the opposite side of the piston
7. Take care not to score gasket surfaces.
8. Replace all gaskets.
9. Clean the crankcase and replace the oil.
