Heat Controller BHD-501-G Sealed Refrigeration System Repairs, Checking the Internal Overload

Heat Controller, Inc. Portable Dehumidifier with R-410A BHD-G Service Manual

TERMINAL OVERLOAD (Internal)

Some model compressors are equipped with an internal overload. The overload is embedded in the motor windings to sense the winding temperature and/or current draw. The overload is connected in series with the common motor terminal.

Should the internal temperature and/or current draw become excessive, the contacts in the overload will open, turning off the compressor. The overload will automatically reset, but may require several hours before the heat is dissipated.

CHECKING THE INTERNAL OVERLOAD

1.With no power to unit, remove the leads from the compressor terminals.

2.Using an ohmmeter, test continuity between terminals C-S and C-R. If not continuous, the compressor overload is open and the compressor must be replaced.

5.2SEALED REFRIGERATION SYSTEM REPAIRS

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 on the high side of the system by installing a line tap on the line.

Apply gauge from line to EPA approved gauges from line to EPA approved recovery system. Recover CFCs in system to at least 5%.

2.Cut the line below, pinch off the suction side of the compressor.

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

4.Add dry nitrogen through the system and unsolder the more distant connection first. (Filter drier, high side process tube, etc.)

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

6.Pressurize system to 30 PSIG with proper refrigerant and boost 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 sped up 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. Recover refrigerant, and proceed with evacuation of a pressure of 200 microns or a minimum of 10%.

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