American Water Heater GAS-FIRED COMMERCIAL WATER HEATER For 24 volts between red

Index

Test or Condition: Result: Action Taken:

Are burners operating?

If pilot does not light and pilot is		Check flue damper wiring.
not sparking, check to make sure		Check for 24 volts at yellow wire
flue damper is in the full open		from thermostat to damper. If
position. Damper opens?		damper still does not open check
YES↓	NO→	for 24 volts between red and
		white wires to damper. If damper
		does not open when voltage is
		present and thermostat is closed,
		replace damper operator.
If damper opens, but pilot does		Check black wire from damper
light or spark:		for 24 volts to ground. If no
		voltage is present, but damper is
		open and voltage is present
		between yellow wire and ground,
		end switch in damper may be
		faulty. Replace damper operator.
Does pilot spark without lighting		If the pilot valve will not open
pilot? Make sure there is		when voltage is present to the to
sufficient gas pressure at the gas		the PV terminal and the common
valve inlet. Check the nameplate		terminal “PV/MV” wire has
for minimum gas supply		continuity to the module, the gas
pressures for the type of gas		valve may be defective. If no
used. Check for plugged pilot		voltage is present at “PV” on the
orifice.		ignition control and the ECO is
		closed (power to 24V and 24V
		GND terminals of module) the
		ignition control module may be
		defective. Replace and recheck
		system.
Check gas valve by measuring		Make sure pilot flame is steady
voltage from “PV” to ground. If		and envelopes the electrode or
no voltage, check continuity		flame sensor. Turn pilot
across ECO circuit of thermostat		adjustment screw counter-
(red wires). If ECO is open, it		clockwise to increase size of pilot
should reset after tank cools		flame. Make sure pilot shield is
below 160°F (71°C). If it does		in place.
not reset, replace sensing bulb
with the ECO. If ECO has
opened, there may be a problem
with the thermostat.
Pilot lights, but main gas does		If pilot flame is stable, check for
not come on.		voltage at the “MV” terminal at
		the ignition module and gas
		valve. If no voltage is present at
		the ignition module, replace
		control. If voltage is present at
		the gas valve, replace valve.

Troubleshooting Procedure for Electronic Thermostat (continued)-

If water temperature is too cold or heater does not come on, proceed as follows (continued from table above):

Test or Condition:	Result:	Action Taken:
If power is not present at the	Disconnect sensor leads from	Sensor(s) may be shorted or
“NO” terminal of the	electronic control module and	open. Check continuity of

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