Quest CDG 174 Installation, Operation and Maintenance Instructions
1-877-420-1330
8www.QuestClimate.com
6.2 Technical Description
The Quest CDG 174 uses a refrigeration system similar to an air conditioner’s to remove heat and moisture from incoming air, and
to add heat to the air that is discharged (see Fig. 2).
Hot, high pressure refrigerant gas is routed from the compressor
to the condenser coil (see Figure 2). 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.
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.
6.3 Troubleshooting
No dehumidification, neither hour meter display nor compressor run and POWER button does not turn ON.
1. Unit unplugged or no power to outlet
2. Defective control board
3. Loose connection in internal wiring
No dehumidification, neither hour meter display nor compressor run with POWER button ON.
1. Defective control board
2. Loose connection in internal wiring
Some dehumidification, air mover runs continuously but compressor only runs sporadically.
1. Unit is in defrost cycle, DEFROST light on
2. Check to make sure humidistat is set high enough
3. Defrost thermistor defective or loose
4. Loose connection in compressor circuit
5. Defective compressor overload
6. Defective compressor
7. Defective relay
8. Low refrigerant charge
Figure 2: Refrigeration system of Quest
