Table 5. Troubleshooting Guide
Symptom
Possible Reason
Troubleshooting Procedure
Dehumidifier does not
turn on/run.
No power to unit.
• Check that the dehumidifier is plugged in.
• Check that the power switch is turned ON.
• Check that the control is turned ON.
• Check that the circuit breaker has not tripped.
Dehumidifier blower is
running but with little
or no airflow.
Pressure drop across
dehumidifier is
higher than 0.4"w.c.
for HCWHD3-070,
0.6"w.c. for
HCWHD3-095, or
0.7"w.c. for
HCWHD3-130.
• Check dehumidifier air filter and wash or replace.
• Check for blocked duct and clear.
• Verify that the outlet collar with backflow damper is installed on the outlet side of the
dehumidifier.
• Check if backflow damper is blocked or stuck and remove obstruction.
Dehumidifier blower
is running but
compressor is not.
Float switch open.
• If float switch installed, check connections at control board and empty condensate pan.
• If no float switch installed check that the jumper is installed at the float switch terminals on the
control board.
Coil frosting.
• Lack of or reduced airflow. Check dehumidifier air filter and wash or replace.
• Check for blocked duct.
• Inlet air conditions below 60°F. Increase the humidity setting.
Inlet air temperature
is outside of the
50°F – 104°F range
or the dew point
is below 40°F and
there is a demand for
dehumidification.
• Verify all duct is properly sealed.
When zoned, the
dehumidifier damper
does not open in
INSTALLER TEST
mode.
Incorrect damper
wiring or bad
connection.
• Verify wiring between dampers and 24 VAC transformer.
• If wired for Two Zone operation, verify that 24 VAC transformer is 40 VA minimum.
• Check all wiring connections between dampers and control board.
• Verify the normally closed dampers are in the Primary Zone duct system and the normally
open dampers are in the Secondary Zone duct system.
The ventilation
damper does not open
when the HVAC fan is
active.
Cycle time has been
met.
• The damper will not open if the Ventilation Time has already been met.
ODT error or outdoor
air outside of ODT
range.
• Check that the ODT is wired correctly to the
dehumidifier control board and connections are
secure.
• Check that the ODT is installed in the outdoor
air intake according to the set-up specified in the
Ventilation Section beginning on page 16.
• Remove the ODT leads from the dehumidifier
control board and check the resistance. Compare
the reading with the table shown.
Outdoor
Temperature
Resistance
0°F
84,500 Ohms
20°F
46,000 Ohms
40°F
26,000 Ohms
60°F
15,500 Ohms
80°F
9,500 Ohms
100°F
6,000 Ohms
Dehumidifier is not
draining properly.
Drain line blocked or
unit not level.
• Verify that the unit is level.
• Check the drain line blockages and for a continuous downward slope.
The HVAC fan turns
on unexpectedly.
Dehumidifier is
sampling or ventilation
in progress.
• The dehumidifier will turn on the HVAC fan during air sampling or as needed to meet the
ventilation time.
Dehumidifier is
producing hot air.
Normal function.
• Air is reheated across the condenser coil, resulting in a temperature rise between inlet and
outlet.
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