CAUTION: Do not touch the oil from a burnt out compressor as the acid will cause a burn. Always wear rubber gloves. Also, safety goggles will protect the eyes when discharging a system.
1. Remove the filter-drier.
2. Remove the compressor.
3. Flush the condenser with Nitrogen or CO2 gas. To do this, purge the system by forcing Carbon Dioxide or Nitrogen gas from the line disconnected from the compressor discharge line and out the line disconnected from the filter-drier. Do this for at least twenty seconds for average size units to clean the high side of the system by forcing the contaminated oil out of the system.
Many condensers have a strainer in their last pass. This strainer must be removed before flushing. The new drier has a strainer which will take its place. (See fig. 142.)
4. Disconnect the capillary tube from the evaporator, and flush the evaporator with CO or Nitrogen gas for at least eight seconds.
5. Install a new compressor, a new filter-drier, and then reconnect the tubing. (See p. 108.)
tubing. (See p. 108.)
6. A new suction-line filter-drier will have to be installed on the suction line after a compressor burnout too.
7. For residential units, charge the unit with about five ounces of the same type of refrigerant used in the system. For commercial units, charge until the head pressure rises above atmospheric pressure. Stop charging, turn on the unit and let the unit run for five minutes, then purge the system. (Refer to pp. 100 through 110 for procedures for evacuation and charging a sealed system.)
8. Repeat step 7 two more times.
9. Using a vacuum pump, evacuate the system and allow the pump to run for thirty minutes. (See page 117.)
10. Recharge the system with the proper refrigerant as indicated on the nameplate of the unit as instructed in the section on charging the system.
REPLACING A BOLTED-TYPE COMPRESSOR
1. Turn the valve stems on both the high- and low-pressure sides all the way clockwise to seal off the refrigerant in the commercial system.
2. Remove the bolts connecting both service valves to the compressor and unbolt
the compressor from the chassis. Disconnect power, detach wires, and remove the compressor.
3. Install the new compressor by reconnecting both service valves and the wires to the proper terminals in the new unit. The new compressor comes with new gaskets to be placed on the compressor high and low side connections after you have moistened them with a little compressor oil. (In these cases, the refrigerant does not have to be discharged from the system.)
4. Turn the high- and low-pressure service valve stems all the way counterclockwise to restore refrigerant circulation (see figs. 102, 120, and 121.)