A.O. Smith DB/DW-720-1810 - Manual (Page 38)

38
PILOT BURNER LIGHTS BUT MAIN BURNER DOES NOT LIGHT
Correct the situation by consulting NO
the installation or user’s manual Does the pilot flame cover 3/8° to 1/2"
on how to adjust pilot flame. (10 mm to 12 mm) of igniter/sensor rod?
YES
Replace
ignition
NO NO
module. Is voltage (24 Vac) across Does spark stay on for more than 30 seconds
terminals MV and MV/PV? after the pilot is “proven” (lit)?
YES
Attach
wires
NO Are the wires securely attached to the main
firmly. valve operator on the gas control and to
terminals MV and MV/PV on ignition module?
YES
YES
Replace main gas valve.
Ensure the ground wire and igntion cable are
separate from each other (prevents shorting
out).
NO
Replace cable and/or Are they in good condition (not brittle,
ground wire. burnt or cracked?
YES
NO Is the ceramic insulater surrounding the
Replace pilot burner. igniter/sensor rod in good condition (not
broken or cracked)?
YES
Clean rod or replace NO Is the igniter/sensor rod in good condition
pilot burner if necessary. (not worn, corroded, sooted or damaged)?
YES
Replace ignition module.