Manual 2100-643C
Page
44 of 59
Signal
Description
Possible Cause
Component to Check
Recommended Action
Device
Actions
DC Free Cooling
Damper Fails to
Close Alarm
Alarm is reset
automatically.
DC free cooling damper
fails to close.
Check the damper
linkage. Check to see
if anything is in the
way of the damper.
Indoor Blower:
On
Damper: Off
Communication
Failed Alarm
Alarm is reset
automatically.
Communication is lost
with the LC Series
main controller.
Check the RS485
port. Check for
damage to the
communications
cable between the
controllers.
Reconnect the
communications
cable. If the controller
board RS485 port is
defective, replace.
Supply Air
Temperature
Sensor Failed
Alarm
(B01)
The alarm is activated
if the sensor is faulty, a
sensor wire is loose or
an out-of-range value
is read.
The alarm is activated
if the sensor is faulty, a
sensor wire is loose or
an out-of-range value
is read.
Check the supply air
temperature sensor
wiring.
Check temperature
vs. resistance of
temperature sensor
(see Table 2.3 on
page 31).
Replace the supply
air temperature
sensor.
Outdoor
Temperature
Sensor Failed
Alarm
(B02)
The alarm is activated
if the sensor is faulty, a
sensor wire is loose or
an out-of-range value
is read.
The alarm is activated
if the sensor is faulty, a
sensor wire is loose or
an out-of-range value
is read.
Check the outdoor
temperature sensor
wiring.
Check temperature
vs. resistance of
temperature sensor
(see Table 2.3 on
page 31).
Replace the outdoor
temperature sensor.
Outdoor
Humidity Sensor
Failed Alarm
(B05)
The alarm is activated
if the sensor is faulty, a
sensor wire is loose or
an out-of-range value
is read.
The alarm is activated
if the sensor is faulty, a
sensor wire is loose or
an out-of-range value
is read.
Check the humidity
sensor wiring.
Replace the humidity
sensor.
Return Air
Temperature
Sensor Failed
Alarm
(B03)
The alarm is activated
if the sensor is faulty, a
sensor wire is loose or
an out-of-range value
is read.
The alarm is activated
if the sensor is faulty, a
sensor wire is loose or
an out-of-range value
is read.
Check the return air
temperature sensor
wiring.
Check temperature
vs. resistance of
temperature sensor
(see Table 2.3 on
page 31).
Replace the return air
temperature sensor.
NEED ASSISTANCE?
This document contains the most current product information as of this printing. For
the most up-to-date product information, go to www.bardhvac.com where there are
links to product specifications, installation instructions, replacement parts manuals and
wiring diagrams. Should any assistance be required during the installation or servicing
of this product, contact the Bard Technical Service Department at 419.636.0439.
TROUBLESHOOTING WALL-MOUNT UNIT ALARMS (CONT.)