A.O. Smith TC-049-R2 Service Handbook, Residential Gas And Electric Water Heater, If …, … then

RESIDENTIAL GAS AND ELECTRIC WATER HEATER

SERVICE HANDBOOK

Residential Gas – continued

The instruction manual gives guidelines under “Air Requirements” and “Unconfined “ or “Confined Space” sections. If you want to test for a lack of air:

1.Turn on every appliance and fan that exhausts air from the utility room and/or house. Make sure all windows and doors are closed, as well as chimney dampers.

2.Open a hot water faucet so that the main burner will ignite

3.Remove the outer door of the water heater – not the inner door

4.Monitor the flame characteristics for several minutes

If the flame begins to “yellow” open a door or window, to the outdoors, to see if additional air corrects this back to blue. If it does, the room needs more air supply. Perform draft test at draft hood of water heater with match or smoke source to verify.

	Testing with
	Gas
Manifold	Pressure	Pilot Gas
	Gauge
Gas Pressure		Pressure
Test		Test

Gas pressure checks are done with flowing gas.

Supply gas pressure checks are taken ahead of the gas control and as close to the heater as possible.

Pilot gas pressure checks are taken by using fitting adapters to tap into the pilot gas tubing. Manifold (main burner) gas pressure is measured using the Allen wrench tap on the bottom of the control valve.

Desired gas pressures will be noted on the gas valve label.

If …	… then
supply gas pressure is under desired pressure	• increase supply gas pressure regulator
setting		setting and,
	• increase supply gas piping size.
supply gas pressure is over desired pressure	•	add gas pressure regulator.
	•	reduce setting on existing regulator.
pilot gas pressure is more than +/- .3 inch	replace the control valve.
W.C. from desired
manifold gas pressure is more than +/- .3 inch	replace the control valve.
W.C. from desired

Additional considerations when pilot or main burner flames are too large or too small:

•Incorrect orifice

•Dirt in orifice or gas supply tubing

A.O. Smith Water Products Company	11	Training Department
©2002		Ashland City, Tennessee