Detroit Radiant Products UH-30 Installation, Operation, Maintenance And Parts page 49

UH Series
Were the gas lines
purged of all air?
No
Purge gas lines.
Is the heater properly
grounded? Is the
heater's polarity
correct?
No
Correct grounding or
fix polarity.
LED Diagnostic Codes
United Technologies Circuit Board
LED CODE
GREEN LED STATUS / ERROR
(# of flashes)
STEADY OFF Internal Control Fault or No Power
STEADY ON
1 In Lockout from Failed Ignitions or Flame Losses
2 Pressure Switch Open with Inducer ON
3 Pressure Switch Closed with Inducer OFF
4 Limit Switch is OPEN
5 In Lockout from False Flame
LED CODE
AMBER LED STATUS / ERROR
(# of flashes)
FAST FLASH Flame Present With Gas Valve Off
STEADY ON
Does the heater's gas
Yes
type match the gas
supplied?
No
Contact local
representative or factory.
With a micro ammeter,
Yes
check micro-Amp reading
of flame sensor circuit. Is
it greater than 0.5 micro-
Amps? NOTE: Meter must
be connected in series.
Yes
Check circuit board flash
codes. Replace ignition
module.
Control Ok
Flame is Sensed
Yes
Adjust pressure or
replace gas valve.
No
Replace circuit board.
Fenwal Circuit Board
LED CODE
GREEN LED STATUS / ERROR
(# of flashes)
SLOW FLASH Normal Operation - No Call for Heat
FAST FLASH Normal Operation - Call for Heat
2 Ignition Lockout - No Flame Detected
3 Airflow Fault - Pressure Switch Open or Closed
4 High Limit or Rollout Switch Open
5 Flame Sense Error - Gas Valve Not Energized
STEADY ON
LED CODE
AMBER LED STATUS / ERROR
(# of flashes)
OFF Flame Signal is Below Required Level / No Flame Present
STEADY ON
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4.0 Troubleshooting Guide
Check manifold pressure. Are
you reading within the specified
pressures per the rating plate?
No
Yes
Check circuit board
for flash codes.
Consult factory.
Internal Control Failure
Flame is Sensed