Product Manual
Form #43471010
Mar 09 -29-
20.0) TROUBLESHOOTING GUIDE
Turn on line voltage
and thermostat. Does
the green monitoring
light come on?
Yes
No
Is there 120V
between the L1 and
L2 terminals on the
terminal block in the
control cabinet?
Yes
No
Are the black lead
wires of the green
light securely on the
terminals?
No
Yes
Replace the green
light.
Repair connection.
Check line voltage at
thermostat and line
voltage curcuit. Repair
fault.
Is the draft inducer
on?
Yes
No
Are the black and
white lead wires of the
draft inducer securely
on the terminals L1
and L2?
No
Yes
Repair connection.
Is 120V on the
terminal of the black
lead wire of the draft
inducer motor?
Does the red
monitoring light come
on?
Yes
No
Is there 24 vac
between terminals of
the transformer on the
secondary side?
Yes
No
Check the terminal
block for continuity;
replace it if no
continuity.
Repair connections.
Is the air hose
securely connected to
the air switch and the
air sensing tubing at
the blower?
No
Clean out hose and
probe.
Troubleshooting
continued on the next
page.
No
Yes
Check terminal block
for continuity. Replace
it if no continuity.
Disconnect the power
and check motor lead
wires. Any wire
broken?
Yes
No
Repair broken wires.
Check the blower
wheel. Does it turn
freely?
Yes
Replace motor
Check blower wheel.
Is there any damage?
Replace blower
wheel.
Readjust blower
wheel on shaft &
retighten set crew.
Check the air sensing
tube and hose. Are
they clear and
unobstructed?
Check the pressure at
the air switch. Is it
higher than the
minimum required?
Is the red wire from
transformer securely
connected to air
switch terminal C?
Move the red wire to
air switch terminal C.
Replace the red
monitoring light.
Is one wire of the red
light connected to air
switch terminal NO?
No
Yes
Replace transformer.
Are the black and
white wires to the
transformer securely
on the terminals?
No
Yes
Repair connection.
No
No
Yes
No
No
Check the voltage
between air switch
terminal C and
ground, is it 24 vac?
Yes
Is there120 vac on the
primary side of the
transformer?
Yes
No
When the blower is
running, is there 24
vac between air
switch terminal NO
and ground ?
No
Move the wire to air
switch terminal NO.
Is the other wire of the
red light connected to
the terminal common
of transformer?
No
Yes
Connect this wire of
the red light to the
transformer terminal
along with the white
wire from ignition
module.
Yes
Yes
No
Yes
Yes
Check the red wire
from transformer for
continuity.
Replace it if no
continuity.
Yes
Replace the air
switch.
No
Check the air intake
and vent. Are there
any blockages?
Yes
No
Remove blockage.
Restart
troubleshooting.
Check vent and fresh
air lengths. Are they
within the maximum
permissible?
No
Yes
Reduce them within
the maximum
permissible.
Remove the blower.
Is the wheel free from
dirt and dust?
Clean the blower
wheel.
Restart
troubleshooting.
No
Yes
Does the blower turn
freely?
No
Yes
Replace the blower
assembly.
Check the restrictor
plate stamped ID. Is
it correct for the
heater?
No
Yes
Replace the restrictor
plate.
Contact factory for
assistance.