TROUBLESHOOTING
(CONTINUED)
TABLE 6 – Troubleshooting Guide
Symptom
Possible Reason
Troubleshooting Procedure
Ventilator does not turn
on/run .
No power to unit .
• Check that the ventilator 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 .
Ventilator blower is
running but with little or
no airflow .
Pressure drop across
ventilator is higher than
0 .4”w .c .
• Check ventilator air filter and wash or replace .
• Check for blocked duct work and clear .
• Verify that the outlet collar with backflow damper is installed on the outlet side of the ventilator .
• Check if backflow damper is blocked or stuck and remove obstruction .
Ventilator 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 ventilator air filter and wash or replace .
• Check for blocked duct work .
• 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 ductwork is properly sealed .
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 .
Ventilator 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 .
Ventilator is sampling or
ventilation in progress .
• The ventilator will turn on the HVAC fan during air sampling or as needed to meet the ventilation
time .
Ventilator is producing
hot air .
Normal function .
• Air is reheated across the condenser coil, resulting in a temperature rise between inlet and outlet .
Display shows “OFF”
even when the ON/OFF
button is pushed .
A manual override
switch has been
installed and has turned
the unit OFF .
• Turn the manual override switch OFF .
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