Detroit Radiant Products Company DET3 Series - Manual (Page 15)

15
DET3 Series 4.0 Troubleshooting Guide
Correct wiring or
replace relay.
The blower is faulty
and must be replaced.
Is there 120VAC coming to the
fan from the low fire relay?
Yes
Is the inlet or outlet of
the unit obstructed? i.e.
ice, birds nest, dirt, etc.
Check for loose wiring
or restrictions in hose
connections to the pressure
switch. Are they ok?
Remove obstruction
No
Yes
No
Repair wiring or hose
connections.
No
The heater is equipped with a safety differential
pressure switch. The switch is a normally
open switch and is located in the air chamber.
Temporarilly place a jumper across the terminal of
the switch. Does the igniter spark?
Yes
Replace the pressure switch after verifying the
following:
• Baffle(s) is in the tube farthest from the burner.
• Heater, blower, squirrel cage, intake and
exhaust are clean and free from dirt and
obstructions.
• The 4 in. dia. air intake pipe does not exceed
20 ft. and/or two elbows.
• There is not a negative pressure experienced
at the area of air intake (i.e. attic space, high
winds, very tight buildings, etc.)
If any of the above were occurring, please
address the problem.
Yes
While the switch is
temporarily bypassed,
check for 120VAC from
the switch to the circuit
board. Does 120VAC
enter the circuit board?
No
Replace circuit board.
Faulty wiring.
Repair or
replace wiring.
Yes No
Key
Start
Question
Process
Question
Corrective
Action
*
* NOTICE 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.