Service Manual

36
36
120 volt potential exposure. Use caution making voltage
checks to avoid personal injury. Flame sensor may be
too hot to handle, take necessary precautions.
WARNING
Service Procedure VI:
Flame Sensor Testing and Replacement
Flame Sensor Testing Procedure
Refer to illustration below,
is there a minimum of 1 µA
during 1.5 second flame
proving period?
Y
Flame sensing circuit O.K.
Call Technical Support.
With flame sensor
disconnected from ignition
module, check continuity to
ground. Is there continuity
to ground?
Replace flame
sensor with gasket
and/or wire lead
(see Flame Sensor
Replacement
Procedure, pg 51).
Remove flame sensor from
water heater. Check
continuity from tip of flame
sensor to end of wire lead.
Is there continuity?
Clean or replace flame sensor
(see Flame Sensor Replacement
Procedure, pg 36).
Replace flame sensor
(see Flame Sensor
Replacement
Procedure, pg 36).
Y
Y
Y
Y
N
N
N
N
Y
N
Call Technical Support.
N
Refer to ignition
module/control board
illustraion (24 volts should
maintain beyond the 1.5
second flame proving period).
Is there 24 VAC across brown
and blue wires coming out of
the control harness?
Is flame sensor free of
oxidation?
Is ceramic of flame
sensor cracked?