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EN
Diagnostic Procedures Water Heater
Component Diagnostic Question Action Based On Status Page
Control Board (Standard and EXT) Continued
Gas/Electric Combination
Control Board
Gas Only Control Board
• Confirm that the E.C.O. is not an open
circuit.
32
• Confirm that the gas solenoid valve has
resistance.
35
If all of the checks are confirmed, replace the
control board.
I
When the E.C.O. is open or the gas
solenoid valve has no resistance, you
may see some voltage (around 9 volts)
on the red wire or yellow wire, but not
enough to open the gas solenoid valve
or energize the 110 V relay.
37
GAS BOARD AND GAS/ELECTRIC COMBINATION
BOARD
Check for power going out from the ignitor on
the control board. Unplug the electrode from
the ignitor on the control board and cycle.
• If there is no spark, replace the control
board.
37
• If the control board does send spark,
replace the electrode.
38
E.C.O.
Does the gas solenoid valve fail to open
and no spark is present?
Does the gas/electric combination
model fail to operate using either gas or
electric power?
If yes, check for continuity. 32
If there is no continuity, replace the E.C.O. 33
On Demand Models: when the water
is running, does the appliance fail to
attempt ignition and the fan fail to run?
Reset the E.C.O. 50
Check for continuity. 32
If there is no continuity, replace the E.C.O. 33
Does the E.C.O. trip repeatedly? On Demand Models Only: Check if the
incoming water temperature is too hot.
27
If so, confirm that the thermostat is seated on
the tank properly.
11
If the thermostat is seated properly, but the
water is getting too hot, replace the E.C.O.
and thermostat.
33
Perform all checks to determine if the E.C.O. is
defective. If so, replace the E.C.O.
33
Electrode
Does the gas solenoid valve open, with
no spark present?
Does the gas solenoid valve open and
there is a spark, but there is no ignition?
Does the gas solenoid valve fail to open
and no spark is present?
On Demand Models: when the water
is running, does the fan run, but the
appliance fails to attempt ignition?
Perform the following checks:
• Confirm there is a gap of 1/8 in.
(3 mm) between the ground wire and
the electrode. If the gap is larger or
smaller than the specification, adjust the
electrode.
39
• Confirm the electrode is not arcing other
than on the tip of the spark probe.
38
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