Burner Assembly - A.O. Smith 100 Series Service Handbook

BURNER ASSEMBLY

The burner is a stainless steel radial fire burner with a woven steel fiber surface. It is installed in the center of the horizontal heat
exchanger. The burner is mounted inside the recess of the heat exchanger.
The spark igniter on the boiler/water heater is a 120VAC igniter. The igniter receives power from the J5 socket on the Control Board.
The 110V from the board is then passed to an ignition transformer. From the ignition transformer the spark ignitier is energized.
A Low/High Gas Pressure Switch is installed on the gas manifold. The Low Pressure Gas Switch is a normally open switch that closes
on a rise in pressure. Switch contacts closes in between +4" W.C.(minimum) - +14" W.C.(maximum) on natural gas models and +4"
W.C.(minimum) - +14" W.C.(maximum) on propane gas models. The High Gas Pressure Switch is normally closed and is used to
detect excessive gas pressure.
Boilers/water heaters have only one flame sensor per individual burner. The flame sensor is mounted close to the burner to sense
the flame firing rates.
FIGURE 7. BURNER ASSEMBLY (1000/2000)
Servicing should only be performed by a Qualified Service Agent 15