Friedrich CP18N30, CP24N30, CP14N10 manual Sealed Refrigeration System Repairs, Equipment Required

Sealed Refrigeration System Repairs

IMPORTANT

ANY SEALED SYSTEM REPAIRS TO COOL-ONLY MODELS REQUIRE THE INSTALLATION OF A LIQUID LINE DRIER.

ALSO, ANY SEALED SYSTEM REPAIRS TO HEAT PUMP MODELS REQUIRE THE INSTALLATION OF A SUCTION LINE DRIER.

EQUIPMENT REQUIRED

1.Voltmeter

2.Ammeter

3.Ohmmeter

4.E.P.A. Approved Refrigerant Recovery System.

5.Vacuum Pump (capable of 200 microns or less vacuum.)

6.Acetylene Welder

7.Electronic Halogen Leak Detector (G.E. Type H-6 or equivalent.)

8.Accurate refrigerant charge measuring device such as:

a.Balance Scales - 1/2 oz. accuracy

b.Charging Board - 1/2 oz. accuracy

9.High Pressure Gauge - (0 - 400 lbs.)

10.Low Pressure Gauge - (30 - 150 lbs.)

11.Vacuum Gauge - (0 - 1000 microns)

EQUIPMENT MUST BE CAPABLE OF:

1.Recovery CFC’s as low as 5%.

2.Evacuation from both the high side and low side of the system simultaneously.

3.Introducing refrigerant charge into high side of the system.

4.Accurately weighing the refrigerant charge actually introduced into the system.

5.Facilities for flowing nitrogen through refrigeration tubing during all brazing processes.

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 gauge from process tube to EPA approved gauges from process tube to EPA approved recovery system. Recover CFC’s in system to at least 5%.

2.Cut the process tube below pinch off on the suction side of the compressor.

3.Connect the line from the nitrogen tank to the suction process tube.

HERMETIC COMPONENT REPLACEMENT cont’d

6.Pressurizesystemto30PSIGwithproperrefrigerantandboost refrigerant pressure to 150 PSIG with dry nitrogen.

7.Leak test complete system with electric halogen leak detector, correcting any leaks found.

8.Reduce the system to zero gauge pressure.

9.Connect vacuum pump to high side and low side of system with deep vacuum hoses, or copper tubing. (Do not use regular hoses.)

10.Evacuate system to maximum absolute holding pressure of 200 microns or less. NOTE: This process can be accelerated by 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 system a minimum of 10 minutes. Release refrigerant, and proceed with evacuation of a pressure of 200 microns or less.

11.Break vacuum by charging system from the high side with the correct amount of liquid refrigerant specified. This will prevent boiling the oil out of the crankcase, and damage to the compressor due to over heating.

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.

12.Restart unit several times after allowing pressures to stabilize. Pinch off process tubes, cut and solder the ends. Remove pinch off tool, and leak check the process tube ends.

SPECIAL PROCEDURE IN THE CASE OF COMPRESSOR MOTOR BURNOUT

1.Recover all refrigerant and oil from the system.

2.Remove compressor, capillary tube and filter drier from the system.

3.Flush evaporator condenser and all connecting tubing with dry nitrogen or equivalent, to remove all contamination from system. Inspect suction and discharge line for carbon deposits. Remove and clean if necessary.

4.Reassemble the system, including new drier strainer and capillary tube.

5.Proceed with processing as outlined under hermetic component replacement.

ROTARY COMPRESSOR SPECIAL TROUBLESHOOTING AND SERVICE

4.Drift dry nitrogen through the system and un-solder the more distant connection first. (Filter drier, high side process tube, etc.)

5.Replace inoperative component, and always install a new filter drier. Drift dry nitrogen through the system when making these connections.

Basically, troubleshooting and servicing rotary compressors is the same as on the reciprocating compressor with only one main exception:

NEVER, under any circumstances, charge a rotary compressor through the LOW side. Doing so would cause permanent damage to the new compressor.

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