Service Manual

86
Service Procedure VII
Flame Sensor Testing and Replacement
Flame Sensor Testing Procedure
WARNING
120 volt potential exposure. Use caution
making voltage checks to avoid personal
injury. Flame sensor may be too hot to
handle, take necessary precautions.
N
Refer to image below.
Is there a minimum of
1 microamp during 1.5
second flame proving
period?
Refer to ignition module/control board image (24 volts
should maintain beyond the 1.5 second flame proving
period.)
Is there 24VAC between P5(5) and P5(8)?
Flame sensing
circuit O.K.
0
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 87).
Remove flame sensor from the water heater. Check continuity from tip of
flame sensor to end of wire lead. Is there continuity?
Is flame sensor free of oxidation?
Is ceramic of flame sensor cracked?
Call Technical
Support.
Clean or replace flame sensor
(see Flame Sensor Replacement
Procedure, pg 87).
Replace flame sensor (see
Flame Sensor Replacement
Procedure, pg 87).
N
N
N
N
N
Y
Y
Y
Y
Y
Y
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