Therma-Stor Products Group UA-135H owner manual Service, Technical Description, Troubleshooting

FOR HVAC INSTALLER AND HOMEOWNER

6. Service

CAUTION: Servicing the UA-135H 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.

2.Defective compressor overload.

3.Defective compressor.

4.Defrost thermostat defective.

5.Dirty air filter(s) or airflow restricted.

6.Low refrigerant charge, causing defrost control to cycle.

7.Bad connection in compressor circuit. Impeller fan does not run with fan switch in either position.

6.1 Technical Description

The UA-135H 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. Hot, high-pressure refrigerant gas is routed from the compressor to the condenser coil (See Figure 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 causes the refrigerant pressure and temperature to drop. It next enters the evaporator coil where it absorbs heat from the incoming air and evaporates. 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 nearly 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

6.2 Troubleshooting

No dehumidification, neither impeller fan nor compressor run with fan switch and ventilation timer OFF.

1.Unit unplugged or no power to outlet.

2.Humidity control set too high or defective.

3.Loose connection in internal or control wiring.

4.Defective Compressor relay.

5.Defective control transformer.

6.Low pressure Control open.

7.Optional Condensate Pump Safety Switch open.

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

1.Defective compressor run capacitor.

2.Bad connection in compressor circuit.

3.Defective compressor overload.

4.Defective compressor.

5.Defrost thermostat open.

Impeller fan runs with fan switch and ventilation timer OFF, but compressor cycles on & off.

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

Impeller fan does not run with ventilation timer activated. Compressor runs briefly but cycles on & off with humidity control turned to ON.

1.Loose connection in impeller fan circuit.

2.Obstruction prevents impeller fan rotation.

3.Defective impeller fan.

4.Defective impeller fan relay.

5.Defective impeller fan capacitor.

Impeller fan runs with fan switch ON. Impeller fan does not run with ventilation timer activated.

1.Defective ventilation timer.

2.Time not correct on ventilation timer.

3.Ventilation timer set to manual & switched OFF.

4.Defective fan switch.

Evaporator coil frosted continuously, low dehumidifying capacity.

1.Defrost thermostat loose or defective.

2.Low refrigerant charge

3.Dirty air filter(s) or airflow restricted.

4.Excessively restrictive ducting connected to unit.

Unit not providing ventilation. Ventilation timer not operating correctly.

1.If timer is not functioning correctly reset timer and reprogram.

2.Check control wire connections (check connections at fresh air damper also).

3.Defective fresh air damper.

4.Defective fan switch.

Unit removes some water, but not as much as expected.

1.Air temperature and/or humidity have dropped.

2.Humidity meter and or thermometer used are out of calibration.

3.Unit has entered defrost cycle.

4.Air filter dirty.

5.Defective defrost thermostat.

6.Low refrigerant charge.

7.Air leak such as loose cover or ducting leaks.

8.Defective compressor.

9.Restrictive ducting.

10.Optional Condensate Pump Safety Switch open.

Unit Test to determine problem:

1.Detach field control wiring connections from main unit.

2.Connect the yellow and green pigtails from the main unit together;

15 Ultra-Aire 135H Installer’s & Owner’s Manual