A.O. Smith TC-049R3 Service Handbook page 12

RESIDENTIAL GAS AND ELECTRIC WATER HEATER
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.
Manifold
Gas Pressure
Test
Gas pressure checks are done with flowing gas.
Supply gas pressure
possible.
Pilot gas pressure
Manifold (main burner) gas pressure
of the control valve.
Desired gas pressures will be noted on the gas valve label.
If ...
supply gas pressure is under desired pressure
setting
supply gas pressure is over desired pressure
pilot gas pressure is more than +/- .3 inch
W.C. from desired
manifold gas pressure is more than +/- .3 inch
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
©2005
SERVICE HANDBOOK
checks are taken ahead of the gas control and as close to the heater as
checks are taken by using fitting adapters to tap into the pilot gas tubing.
Testing with
Gas
Pressure
Gauge
is measured using the Allen wrench tap on the bottom
... then
•
increase supply gas pressure regulator
setting and,
•
increase supply gas piping size.
•
add gas pressure regulator.
•
reduce setting on existing regulator.
replace the control valve.
replace the control valve.
11
Technical Training Department
Ashland City, TN
Pilot Gas
Pressure
Test