Detroit Radiant Products Company DX3 Series - Manual (Page 15)

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.
Is 120V coming
to the fan?
Check for loose wiring
or resistance in hose
connection to pressure
switch. Are they ok?
The heater is equipped with a safety pressure
switch. This differential switch, located in the controls
compartment, is a normally open pressure switch.
Temporarily place jumpers across the terminals of the
switch. Does the light energize?
15
4.0 Troubleshooting Guide
Key
Start
Question
Process
Question
Corrective
Action
DX3 Series
Yes
No
The fan is faulty
and must be
replaced.
Correct
wiring.
Repair.
No
Yes
Yes
Replace faulty light.
No
Replace the differential switch after verifying the following:
• Baffle(s) is/are in the radiant tube(s) farthest from the burner.
• The heater, fan blower, squirrel cage, intake and exhaust are free from
dirt and obstructions.
• The 4” air intake pipe does not exceed 20 feet and/or 2 elbows.
• There is not a negative pressure experienced at the area of air intake
(i.e., attic space, high winds, very tight building).
If any of the above are occurring, please address the problem.
Is resistance through
the igniter 50-400
Ω ?
Replace
igniter.
No
Consult
factory.
Yes
Check to make sure gas
pressure is within minimum
and maximum inputs, as
indicated on burner rating
plate. Is gas pressure OK?
Replace gas valve.
Yes
Correct problem.
No