Service, Warranty, Technical Description

5 Service

CAUTION: Servicing the DH-100V with its high- pressure refrigerant system and high voltage circuitry presents a health hazard, which could result in death, serious bodily injury, and/or property damage. Only qualified service people should service this unit.

5.1 Warranty

See page 9 for warranty terms. Read the warranty before any repair is initiated. If a warranty repair is required, call the factory first at 1-800-255-7749 for warranty claim authorization and technical assistance.

5.2 Technical Description

The DH-100V uses a refrigeration system similar to an air conditioner's to remove heat and moisture from incoming air, and add heat to the air that is discharged (see Fig. 1).

Hot, high-pressure refrigerant gas is routed from the compressor to the condenser coil (see Fig. 1). The refrigerant is cooled and condensed by giving up its heat to the air that is about to be discharged from the unit. The refrigerant liquid then passes through a filter/drier and capillary tubing, which cause the refrigerant pressure and temperature to drop. It next enters the evaporator coil where it absorbs heat from the incoming air and evaporates.

Figure 1: Refrigeration System of DH-100V

The evaporator operates in a flooded condition, which means that all the evaporator tubes contain liquid refrigerant during normal operation. A flooded evaporator should maintain constant pressure and temperature across the entire coil, from inlet to outlet.

The mixture of gas and liquid refrigerant enter the accumulator after leaving the evaporator coil. The accumulator prevents any liquid refrigerant from reaching the compressor. The compressor evacuates the cool refrigerant gas from the accumulator and compresses it to a high pressure and temperature to repeat the process.

5.3 Troubleshooting

No dehumidification, neither blower nor compressor run with fan switch OFF.

1.Unit unplugged or no power to outlet.

2.Humidity control set too high or defective (Sec. 3.1 & 5.7).

3.Loose connection in internal wiring.

No dehumidification, compressor does not run but blower runs with fan switch OFF and humidity control turned to ON.

1.Defective compressor run capacitor (Sec. 5.6).

2. Loose connection in compressor circuit	(see
Fig. 2).

3.Defective compressor overload (Sec. 5.6A).

4.Defective compressor (Sec.5.6).

5.Defrost thermostat open (Sec. 5.8).

Blower runs with fan switch OFF, but compressor cycles on & off.

1.Low ambient temperature and/or humidity, causing unit to cycle through defrost mode.

2.Defective compressor overload (Sec. 5.6A).

3.Defective compressor (Sec. 5.6).

4.Defrost thermostat defective (Sec. 5.8).

Blower does not run with fan switch in either position. Compressor runs briefly but cycles on & off.

1.Loose connection in blower circuit (see Fig. 2).

2.Obstruction prevents impeller rotation.

3.Defective blower.

4.Blower switch defective.

Evaporator coil frosted continuously, low dehumidifying capacity.

1.Defrost thermostat loose or defective (Sec. 5.8).

2.Low refrigerant charge

3.Dirty air filter or airflow restricted.