IBC AHU Series User Manual

Fault Code/Error Message Description Possible Fix
Dehumidifier Temperature Sensor Sensor not connected or
faulty.
Check the sensor. For resistance
reading, see Table 13.
Outdoor Temperature Sensor Sensor not connected or
faulty.
Check the sensor. For resistance
reading, see Table 13.
Air In Temp Sensor (Probe) Sensor not connected or
faulty.
Check the sensor. For resistance
reading, see Table 13.
Barometer Probe not connected or
device is faulty.
Check the probe.
Humidistat Probe not connected or
device is faulty.
Check the probe.
Door Open / No Fan Signal Service door is open or fan
fault.
Check door or if door
switch is faulty.
Check if harness is
disconnected.
Check if fan is turning.
No Fan RPM No rotation of the fan is
detected.
Check if fan is turning or
disconnected. Check the fuse.
Use a meter to check 120V is
present on the external connection
to the board. If 10V is not coming
from the fan it is not receiving
120V. Check the 10V signal on
the web app.
A/C Freeze Freezing detected in the A/C
coil.
The coil needs to defrost. Refer to
the manual for the air conditioner
for details on how to prevent
freezing.
Dehumidifier Freeze Freezing detected in the
dehumidifier appliance.
The coil needs to defrost. Refer to
the manual for the dehumidifier for
details on how to prevent freezing.
Thermostat Fault Simultaneous heating and
cooling calls detected
Check that the heating lead has
not been crossed with the cooling
lead from the Nest thermostat.
There is also a known bug related
to some thermostat models that
are over 3 years old: the backing
plate allows a short to signal a call
for cooling.
RTOS Fault 1 Software fault Contact IBC Technical Support
for software upgrade.
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Section: Find troubleshooting for IBC Technologies' air handling appliances.

IBC AHU Series Specifications

General

Brand	IBC
Model	AHU Series
Category	Air Handlers
Language	English