Service Manual

44
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.
Is ceramic of flame
sensor cracked?
Y
Y
Refer to ignition control board
illustration. (24-28 volts should
maintain beyond the 2 second
flame proving period.) Is there
24-28 VAC across brown and
blue wires (gas valve) coming
out of the control board
harness?
Flame sensing circuit O.K.
With flame sensor
disconnected from ignition
control board, check
continuity to ground. Is
there continuity to ground?
Replace flame
sensor with gasket
and/or wire lead
Remove flame sensor from
water heater. Check
continuity from tip of flame
sensor to end of wire lead.
Is there continuity?
Is flame sensor free of
oxidation?
Clean or replace flame sensor.
Call
Technical
Support.
Replace flame sensor
Refer to image below. Is
there a minimum of 1 µA
during 2 second flame
proving period? (may be
checked on digital display).
ICON Control Board Schematic
Y
Y
Y
Y
Y
Y
Y
Y
N
N
N
Y
Y
Call Technical Support.
N
N
N
N
N
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