Service Manual

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Sequence of Operation
Lockout Conditions
The system will go into lock out mode for the following reasons:
1. ERROR CODE 110
a. Control board will go into soft lockout if the main burner cannot be lit or fails to prove flame after 3 ignition trials.
The water heater digital display indicates a lockout condition by showing error code 110 with “Service Needed”
on the control board’s digital display. Refer to error codes in the diagnostic section of this Service Manual. In a
soft lockout condition, the control will wait for 15 minutes and then make 3 more attempts to light the main burners.
Soft lockout reset is accomplished by depressing the lower right button under “Reset” for 3 seconds.
2. ERROR CODE 80
a. If the temperature at the top of the tank should exceed 207°F, then the high limit control will shut off the burner
and the water heater will go into a hard lockout. Error code 80 will be shown on the control board’s digital display.
The control board can only be reset in the Service Mode, which is detailed in the ICON System Troubleshooting
section of this Service Manual (pg 15).
3. ERROR CODE 67
a. If the exhaust terminal becomes blocked or the condensate elbow fails to drain condensate, the normally closed
exhaust pressure switch will open, the gas valve will close, and error code 67 will appear on the digital display.
When the condition is corrected, the error code will disappear, and the water heater will resume normal operation.
No resetting of the control board is needed for the pressure switch error code.
b. If the vent safety switch located near the exhaust pressure switch should open, the gas valve will close, the blower
will post-purge, and error code 67 will appear on the control board’s digital display. The lockout condition will reset
once the problem is corrected and the switch is reset. Refer to Vent Safety Switch Testing and Replacement in
this Service Manual (pg 49).
c. The pressure switch and temperature switch are wired in series. As a result, the water heater will not function
unless both switches are operational.
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