Detroit Radiant Products Company UH Series - Manual (Page 48)

48
UH Series 4.0 Troubleshooting Guide
Do the burners
ignite?
Yes
Continued from page 46.
Do the burners
stay lit?
Yes
Does the air
motor fan turn
on approx. 30
seconds after
ignition?
Yes
Does the heater
stay on until the
call for heat ends?
Yes
Troubleshooting ends.
For more information, contact
your local representative or the
factory for further assistance.
No
Is the gas supply
valve to the heater in
the “on” position?
Turn on gas supply
line.
Yes
Check inlet pressure to the heater. Is it within
the minimum and maximum allowable range
as per the rating plate?
No
Yes
Adjust inlet pressure.
No
No
Do the burners light
and then shut off
immediately (within
1-2 seconds)?
Check inlet pressure
and limit switches.
Yes
Does the burner stay on for approximately
8-10 seconds, and then shut off?
Check circuit board for
flash codes. Consult
factory.
No
No
No
Does the circuit board send 120
VAC to the air movement fan after
approx. 30 seconds after ignition?
Yes
Is the motor dirty, obstructed, or
damaged, inhibiting rotation?
No
Verify wires are not
damaged. Check flash
codes, and then replace
circuit board.
No
Check motor starter capacitor.
Replace or repair.
Clean fan, remove obstruction, or
replace damaged parts.
Yes
No
The heater can shut down or stay on due to:
• Limit switch opening.
• Pressure switch opening.
• Improper grounding.
• Faulty control device.
• High winds.
• Taking combustion air from the attic.
• Dirty environment.
• Fluctuating gas pressure.
Yes