53
CL3
Series
5.0
Maintenance
•
Troubleshooting Guide
Bypassing any switch is intended for testing purposes only. Do not leave switch bypassed during
normal operation or the heater’s built-in safety mechanisms will be compromised.
NOTICE
* Refer to LED diagnostic Fault Code Chart on pg. 51.
Is there 120 V on the
primary side of the internal
transformer?
The circuit board is
faulty and must be
replaced.
Repair wiring between
power in and transformer.
The fan is faulty and must be replaced.
The internal
transformer is
faulty and must
be replaced.
No
Yes
Is the power across
the middle (low)
terminal of 24 V plug
and ground (screw on
the Burner Control
Box) 24 V?
Repair thermostat or wiring from
thermostat to heater.
Is there 24 V
across the TH and
ground terminals
on the circuit
board?
Correct wiring.
Is the circuit
board sending
120 V to the
fan?
Is the fan
obstructed?
Remove ob-
struction.
Is the pressure switch stuck
in the closed position?
Replace
pressure
switch
Yes
Yes
Yes
Yes
Yes
No
No
No
Check for loose wiring or
restrictions in hose connec-
tions to pressure switch.
Are they OK?
Replace wiring or hose connections.
*A
fter 0-30 seconds of
non-operation has passed,
is there a flash code for
APS failure (2 flashes)?
Replace the pressure switch after verifying:
• Baffle(s) are in the radiant tube furthest from
the burner.
• Heater, fan blowers ,squirrel cage, intake and
exhaust are clean and free from dirt and
obstructions.
• The 4” air intake pipe does not exceed 20 ft.
and/or 2 elbows.
• There is not a negative pressure experienced
at the area of air intake (e.g.; high winds, attic
space, tightly sealed building).
Replace circuit board.
No
Yes
Yes
No
No
No
