LAARS U.H.E. - Service Manual - Manual (Page 11)

U.H.E Service Manual Page 11
Determine failure mode by observing flashing LED status on ignition module.
LED status and probable cause shown below.
* Denotes conditions that may require the water heater to be isolated from the vent
system to determine root cause.
LED status & probable cause
For models with Hot Surface Ignition
LED STATUS
Power & flame
light flashing.
Probable Cause
Supply voltage
polarity.
LED STATUS
Valve light flashing.
Probable Cause
Flame sensor.
(see page 32)
Probable Cause
Hot surface igniter.
(see page 30)
Probable Cause*
Combustion system.
(see page 18)
Probable Cause
Blower.
(see page 25)
Probable Cause*
Exhaust pressure
switch. (see page 27)
LED STATUS
Purge light flashing.
LED STATUS
Only power light
is on and water heater
will not function.
Probable Cause
Thermostat circuit.
(see page 12)
Probable Cause*
Exhaust pressure
switch. (see page 27)
Probable Cause
Vent safety switch.
(see page 36)
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