7
NOTE: This procedure can be sped up by the use of
heat lamps, or by breaking the vacuum with refrigerant
or dry nitrogen at 5,000 microns. Pressure system to 5
PSIG and leave in the system a minimum of 10 minutes.
Recover refrigerant, and proceed with evacuation to a
pressure of 200 microns or a minimum of 10%.
11. Break the vacuum by charging the system from the high
side with the correct amount of refrigerant specifi ed. This
will prevent boiling the oil out of the crankcase.
NOTE: If the entire charge will not enter the high side,
allow the remainder to enter the low side in small
increments while operating the unit.
HERMETIC COMPONENT REPLACEMENT
The following procedure applies when replacing components
in the sealed refrigeration circuit or repairing refrigerant leaks.
(Compressor, condenser, evaporator, capillary tube, refrigerant
leaks, etc.)
1. Recover the refrigerant from the system at the process
tube located on the high side of the system by installing
a line tap on the process tube. Apply the gauge from the
process tube to EPA approved gauges from the process
tube to the EPA approved recovery system. Recover the
CFC’s in the system to at least 5%.
2. Cut the process tube below the pinch off in the suction side
of the compressor.
3. Connect the line from the nitrogen tank to the suction
process tube.
4. Drift dry nitrogen through the system and unsolder the
more distant connection first. (Filter drier, high side
process tube, etc.)
5. Replace the inoperative component, and always install a
new fi lter drier. Drift dry nitrogen through the system when
making these connections.
6. Pressurize the system to 30 PSIG with proper refrigerant
and boost the refrigerant pressure to 150 PSIG with dry
nitrogen.
7. Leak test the complete system with the electric halogen
leak detector, correcting any leaks found.
8. Reduce the system to zero gauge pressure.
9. Connect the vacuum pump to the high side and low side
of the system with deep vacuum hoses, or copper tubing.
(Do not use regular hoses.)
10. Evacuate the system to an absolute holding pressure of
200 microns or less.
12. Restart the unit several times after allowing pressures
to stabilize. Pinch off the process tubes, cut and solder
the ends. Remove the pinch off tool, and leak check the
process tube ends.
SPECIAL PROCEDURES IN THE CASE OF
COMPRESSOR MOTOR BURNOUT
1. Recover all refrigerant and oil from the system.
2. Remove the compressor, capillary tube and fi lter drier from
the system.
3. Flush the evaporator, condenser and all connecting tubing
with dry nitrogen, or equivalent, to remove all contamination
from the system. Inspect the suction and discharge lines
for carbon deposits. Remove and clean if necessary.
4. Reassemble the system, including a new drier-strainer and
capillary tube.
5. Proceed with processing as outlined under hermetic
component replacement.
ROTARY COMPRESSOR
SPECIAL TROUBLESHOOTING & SERVICE
Basically, troubleshooting and servicing rotary compressors
is the same as on the reciprocating compressor with only a
few exceptions.
1. Because of the spinning motion of the rotary, the mounts
are critical. If vibration is present, check the mounts
carefully.
2. The electrical terminals on the rotary are in a different order
than the reciprocating compressors. The terminal markings
are on the cover gasket. Use your wiring diagram to insure
the correct connections.
REFRIGERANT CHARGE
1. The refrigerant charge is extremely critical. Measure the
charge carefully and as exactly as possible to the nameplate
charge.
2. The correct method for charging the rotary is to introduce
liquid refrigerant into the high side of the system with the
unit off. Then start the compressor and enter the balance
of the charge, gas only, into the low side.
The introduction of liquid into the low side, without the use of
a capillary tube, will cause damage to the discharge valve
of the rotary compressor.
NOTE:
All inoperative compressors returned to Friedrich
must have all lines properly plugged with the plugs from
the replacement compressor.
