Procedures And Conditions - A.O. Smith TC-049R3 Service Handbook

RESIDENTIAL GAS AND ELECTRIC WATER HEATER
Residential Gas - continued
:
Sooting causes
If ...
the burner is clean but the chamber and/or flue
are sooted
the main burner, chamber and flue are sooted
Electrical Testing
This type of water heater has its own electrical
generating system.
When two dissimilar metals are joined together
and this joint is heated, a small, electrical current
will be produced. A thermocouple uses this
science.
Thermocouple output test
Procedures/Conditions:
Meter set for DC millivolt testing
Test from lower ECO (emergency cut off or energy cut off) solder joint to ground.
Note: If pilot will not stay lit, manually hold the top knob down in the pilot position. This allows
gas to flow to the pilot. Light the pilot and continue to hold this knob down while conducting the
test.
If ...
reading test of at least 13 MV is not present
reading test of at least 13 MV is present
A.O. Smith Water Products Company
©2005
SERVICE HANDBOOK
... then
check for lack of supply air.
check the following:
incorrect orifice
•
excessive gas pressure
•
loose main burner
•
cross threaded orifice
•
gas control valve gas seepage
•
loose gas connection in burner assembly.
•
... then
check that flame contacts end of
•
thermocouple
replace thermocouple.
•
continue to next test.
12
TO GROUND
Technical Training Department
Ashland City, TN