A.O. Smith Water Heater HW-399

Ensure all necessary tools and safety equipment are available

Review safety protocols for handling gas and water leaks

Inspect all visible pipes for signs of water leakage

Is there any visible water leakage?

Describe the location and extent of any water leaks found

Check for the smell of gas near the boiler and gas lines

Ensure the circulator pump is turned off

Verify that the oil tube is available and in good condition

Identify the oil cups to be lubricated

Add 2 or 3 teaspoons of No. 20 non-detergent motor oil to the pump oil cup

Add 10 or 12 drops of No. 20 non-detergent motor oil to each motor oil cup

Was the lubrication process completed successfully?

Turn off the electrical power, main manual gas shutoff, and pilot valves (if applicable).

Allow boiler parts and vent to cool before disassembly.

Remove the boiler draft diverter and vent pipe running to the chimney.

Check parts and chimney for obstructions and clean as necessary.

Remove burner from boiler and other metal parts as required to clean and vacuum the heat exchanger and combustion coils.

Refer to parts list supplied with this manual for disassembly aid.

Inspect the operation of all safety devices including low water cutoffs

Is more frequent inspection required based on water conditions?

Flushing of Low Water Cutoff Device

Flush the low water cutoff device of the float type

Ensure the boiler is not connected to a common vent or chimney with solid fuel burning equipment.

Verify that the equipment room is not under negative pressure.

Inspect the venting system for the following issues

Is there sufficient supply and ventilation air in the equipment room?

Confirm that no unsafe conditions were identified during the inspection.