Dexon Canada Air Systems Inc
OWMDH Series Use Manual
Version 07.2019
Page
17
Figure 3: Fan Stopped Indication
“Power On” LED and “Fan Stopped” LEDs are both lit: Is an indication
that there has be a fan failure or if there is confirmation of the fan
running then possibly issues with the 95DH Main Controller, status
board or TachOP PCB. If fan is not running confirm that there is power
output from the 95DH Main Controller to the fan. If you confirmed the
fan is running and there is still a “Fan Stopped” indication then there is
an issue with one or more of the control boards.
IMPORTANT:
When the “Fan Stopped” LED is lit the heating elements
are disabled for safety. If the outdoor temperature is below 0
°
C this will
lead to a “Low Temp.” shut down condition; if this does occur the “Low
Temp.
” LED will also light up.
“Power On”, “Fan Stopped” and “Low Temp.” LEDs are all lit: In cold
temperatures this is the most common failure indication. This can be
due to a
“Low Temp.” shut down condition which causes the “Fan
Stopped” indication or a “Fan Stopped” indication which activates the
“Low Temp.” shut down feature since the “Fan Stopped” condition will
disable the heating elements. This occurs at temperatures below 0
°
C.
The
“Low Temp” LED can light up due to a lack of heating, the heating
circuit is off or one or more heat sensors are “open”. This is most
commonly due to corroded wire leads in the heat exchanger. It could
also be caused by a temperature sensor failure, a sensor out of
calibration or the 95DH main controller has failed.
The
“Fan Stopped” LED: Will light up in the event of a fan failure or if a
“Low Temp.” condition occurred as described above. Check the fan for
operation and check to ensure the heating circuit is energized (breaker
is on).
The “Low Temp.” LED: Will light up due to a lack of heating; the
heating circuit is off or one or more heat sensors are open. This is most
commonly due to corroded wire leads in the heat exchanger. It could
also be caused by a temperature sensor failure, a sensor out of
calibration or the 95DH Main Controller has failed.
Note
: A “Low Temp.” condition can also occur in Class 1, Div. 2 blower
heaters as they have overheat thermostats mounted directly on each of
the heating elements. These normally closed thermostats shut down
the heating if the heating element skin temperature reaches close to
ignition temperature of the gases in the Gas Groups C & D. There is no
status indication for this condition; check for open contact, corroded
wires etc.
Figure 4:
“Fan Stopped” with
“Low Temp.” Indication
Figure 3: “Fan Stopped”
Indication
