A.O. Smith Water Heater AT-H3M-OS-N

Turn off all electric power to the water heater

Turn the manual gas valve located on the outside of the unit to the off position

Ensure all safety precautions are followed to prevent fire or explosion

Shut off the manual gas valve on the gas supply line

Remove the screw from the pressure port located on the gas inlet of the water heater

Connect the manometer to the pressure port and zero the manometer

Check the venting system for issues

Inspect the burner for dust, lint, grease, or dirt

Close the manual gas shutoff valve

Turn off power to the unit and wait a couple of seconds. Turn on again.

Wait 30 seconds, and then turn off power to the unit.

If the heater is part of an Easy-Link or Multi-Unit System, close the inlet and outlet water valves to isolate the heater.

Open all hot water taps in the house.

Close the manual gas shutoff valve

Turn off power to the unit and wait a couple of seconds. Turn on again

Wait 30 seconds, and then turn off power to the unit

If the heater is part of an Easy-Link or Multi-Unit System, close the inlet and outlet water valves to isolate the heater

Open all hot water taps in the house

Turn off the electrical power supply

Close the manual gas shutoff valve

Close the manual water control valve

Ensure the area around the water heater is free from contaminants

Are all openings for combustion and ventilation air unblocked?

Inspect the screen of the termination for blockages