Replacing an Evaporator
To replace an evaporator, pump down the system
and disconnect the liquid and suction lines. Then
remove the expansion valve and the evaporator. Make
the necessary repairs or install a new evaporator as
required. Replace the expansion valve and connect the
liquid and suction lines. Remove moisture and air by
evacuating the system. When the evaporator is back in
place, pump a deep vacuum as in starting a new
installation for the first time. Check for leaks and
correct them if they occur. If leaks do occur, be certain
to repair them; then pump the system into a deep
vacuum. Repeat the process until no more leaks are
Removing the Compressor
Using the gauge manifold and a vacuum pump,
pump down the system. Most of the refrigerant will be
trapped in the condenser and the receiver. To remove
the compressor from service, proceed as follows:
1. Once the pump down is complete, the suction
valve should already be closed and the suction
gauge should read a vacuum. Mid-seat the
discharge service valve. Open both manifold
valves to allow high-pressure vapor to build up
the compressor crankcase pressure to 0 psi.
2. Front-seat (close) the discharge service valve.
Then crack the suction service valve until the
compound gauge reads 0 to 1 psi to equalize the
pressures and then front-seat the valve.
3. Joints should be cleaned with a grease solvent
and dried before opening. Unbolt the suction
service and discharge service valves from the
compressor. DO NOT remove the suction or
discharge lines from the compressor service
4. Immediately plug all openings through which
refrigerant flows using dry rubber, "cork"
stoppers, or tape.
5. Disconnect the bolts that hold the compressor to
the base and remove the drive belt or disconnect
the drive coupling. You can now remove the
Removing Hermetic Compressors
Systems using hermetic compressors are not easily
repaired, as most of the maintenance performed on
them consists of removal and replacement.
Disconnect the electrical circuit including the
Install a gauge manifold. Use a piercing valve
(Schraider) if needed.
Remove the refrigerant using an EPA approved
Disconnect the suction and discharge lines.
Using a pinching tool, pinch the tubing on both
the suction and discharge lines, and cut both
lines between the compressor and the pinched
Disconnect the bolts holding the compressor to
the base and remove the compressor.
Do not forget to pump down the system and
equalize the suction and head pressure to the
atmosphere, if applicable. Wear goggles to prevent
refrigerant from getting in your eyes. After
replacement, the procedures given for removing air
and moisture and recharging the system can be
followed; however, the procedures may have to be
modified because of the lack of some valves and
connections. Follow the specific procedures
contained in the manufacturer's manual.
What are the two major pieces of maintenance
equipment used for refrigeration work?
Before attempting transfer of refrigerantfrom a
container to a cylinder, you should precool the
receiving cylinder for what reason?
What is the purpose of evacuating a
You should continue to operate the vacuum
pump during evacuation of a system until what
condition is obtained?
What method of charging a system is generally
What are the three methods used to detect
When you pump down a system, where is the