Honeywell TRUEDRY DH150 - Manual (Page 14)

Installation Guide
69-2271EFS—01 12
Problem Recommended Troublshooting Steps
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.
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.
CAUTION: Servicing the TrueDRY DH150 with its high pressure refrigerant system and high voltage cir-
cuitry presents a health hazard which could result in death, serious bodily injury, and/or property damage.
Service should only be performed by a qualified service technician.
Technical Description
Troubleshooting
TrueDRY DH150 uses a refrigeration system similar to an air condi-
tioner 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. 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 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.
CONDENSER
EVAPORATOR
CAPILLARY
TUBES
ACCUMULATOR
COMPRESSOR STRAINER/FILTER
DRIER
M27404