Quest 70 & 155 Dehumidifier Maintenances

QUEST 70 DEHUMIDIFIER

The Quest 70 uses a refrigeration system similar to an air conditioner to remove heat and moisture from incoming air, and add heat to the air that is discharged. The hot, high-pressure refrigerant gas is routed from the compressor to the condenser coil. 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 strainer 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 enters 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 high pressure and temperature.

 

Standard Air Filter

The Quest Dual Dehumidifier ships with a standard MERV 13 efficient pleated fabric filter. This filter should be checked every six months. Operating the unit with a dirty filter will reduce dehumidifier capacity and efficiency and may cause the compressor to cycle off and on unnecessarily on the defrost control.

To access the air filter, remove the filter access panel from the end of the Quest Dual Dehumidifier. The filter should be readily visible and can be removed by pulling it straight out of the Quest Dual Dehumidifier. We recommend changing the filter at least every 6 months. For agriculture, we recommend changing the filter with every grow cycle.

Impeller Fan Oiling The impeller fan motor is factory lubricated for many years of normal operation, and no further oiling is required.

 

QUEST 155 DEHUMIDIFIER

The Quest Dual 155 Dehumidifier uses a refrigeration system similar to an air conditioner to remove heat and moisture from incoming air, and add heat to the air that is discharged. The hot, high-pressure refrigerant gas is routed from the compressor to the condenser coil. 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 enters 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 high pressure and temperature to repeat the process.

 

Standard Air Filter

The Quest Dual Dehumidifier ships with a standard MERV 13 efficient pleated fabric filter. This filter should be checked every six months. Operating the unit with a dirty filter will reduce dehumidifier capacity and efficiency and may cause the compressor to cycle off and on unnecessarily on the defrost control.​

To access the air filter, remove the filter access panel from the end of the Quest Dual Dehumidifier. The filter should be readily visible and can be removed by pulling it straight out of the Quest Dual Dehumidifier. We recommend changing the filter at least every 6 months. For agriculture, we recommend changing the filter with every grow cycle.

Impeller Fan Oiling The impeller fan motor is factory lubricated for many years of normal operation, and no further oiling is required.

 

TROUBLESHOOTING

Q. Neither fan nor compressor running. Dehumidification is being called for. No fan call.

1. Unit unplugged or no power to the outlet.
2. Humidity control set too high.
3. Loose connection in internal or control wiring.
4. Defective Compressor relay.
5. Defective control transformer.

Q. The compressor is not running. Dehumidification is being called for. No fan call.

1. Defective compressor run capacitor.
2. Loose connection in the compressor circuit.
3. Defective compressor overload.
4. Defective compressor.
5. Defrost thermostat open.

Q. Compressor cycles on and off. Dehumidification is being called for. No fan call

1. Low ambient temperature and/or humidity causing unit to cycle through defrost mode.
2. Defective compressor overload.
3. Defective compressor.
4. Defrost thermostat defective.
5. Dirty air filter(s) or airflow restricted.

Q. The fan is not running. Dehumidification or fan is being called for

1. Loose connection in the fan circuit.
2. The obstruction prevents fan impeller rotation.
3. Defective fan.
4. Defective fan relay.

Q. Low dehumidification capacity (evaporator is frosted continuously). Dehumidification is being called for

1. Defrost thermostat defective.
2. Low refrigerant charge
3. Dirty air filter(s) or airflow restricted.
4. Excessively restrictive ducting connected to the unit.

Q. No ventilation. Ventilation is being called for.

1. Loose connection in the ventilation control circuit
2. Loose connection in the damper power circuit.
3. Defective fresh air damper.

Q. The unit removes some water, but not as much as expected.

1. Air temperature and/or humidity have dropped.
2. The humidity meter and or thermometer used are out of calibration.
3. The unit has entered the 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.

Q. Unit Test to determine the problem:

1. Detach field control wiring connections from the main unit.
2. Connect the 24V and FAN terminals from the main unit together; only the fan should run. Disconnect the terminals.
3. Connect the 24V and DEHU terminals from the main unit together; the compressor and fan should run.
4. If these tests work, the main unit is working properly. You should check the control panel and field control wiring for problems next.
5. Remove the control panel from the mounting box and detach it from the field-installed control wiring. Connect the DEHU, COM, and FAN terminals from the control panel directly to the corresponding terminals on the main unit.
6. Leave the violet, white and red wires disconnected! Turn on the fan switch; the fan should run. Turn off the fan switch.
7. Turn on the humidity control; the compressor and fan should run.
8. If these tests work, the problem is most likely in the field control wiring.