A.O. Smith 110-310-510 – CLEANING THE COMBUSTION COMPONENTS

Procedure for cleaning the fan, burner, Flame Sensor and AFR, as used by all Service Representatives.
1)TOOLS ? Gather the following materials together:
a. Degreaser in a pump action bottle, Sandpaper, Philips Screw Driver, Needle?Nosed Pliers, Duct Tape, Flashlight, Air Compressor, Shop Vacuum, 3x Towels
2)POWER ? Disconnect power to your unit by either unplugging it from the wall outlet, or by the circuit breaker, depending on the setup.
3) GAS ? Shut off the gas supply.
4) FRONT COVER ? Remove the front cover.
5)MANIFOLD PLATE/GAS VALVE ASSEMBLY ?
a. Remove the manifold plate screws. They are wide pan head Philips screws, located on the edges of the stamped metal plate of the gas manifold
b. Remove the brass gas valve screw.
c. Remove the wire holding the Easy?Link wires in place.
d. Disconnect the clear plastic tube from beneath the combustion chamber
e. Gently lift up the manifold & gas valve assembly to dislodge it from the gas inlet, and gently let it hang.
i. There is a small filter screen in the bottom of the gas inlet. Do not lose it.

6)BURNER ASSEMBLY ? Now proceed to remove the burner assembly.
a. Remove the five wide pan head Philips screws holding the burner to the combustion chamber.
There are three at the top of the burner. There are two at the bottom of the burner to the back of the combustion chamber.
b. Disconnect the rod assembly: Orange flame sensor, Yellow AFR, Black igniter wire
c. Remove the burner. It may be hard to take out, so try the following:
i. With pliers, grasp between the oval air vents in the front of the burner on the far left and pull firmly. Repeat on the right vent.
ii. Now pull from the center and it should slide out readily.
d. Inspect the gasket. (Minor surface tears are allowable. Major separations are not acceptable.

7)CLEAN THE BURNER – Use degreaser in a pump action bottle.
a. Protect the burner gasket from direct water pressure.
IF the gasket becomes compromised, please contact the Technical Service Department for further assistance.
b. Thoroughly saturate the burner with the cleaning solution from the top, down through the slots, as well as the openings in the front of the burner until the burner is soaking wet.
c. Let the burner sit for 5 minutes.
d. Remove the burner from the solution. Set the burner in a sink in its normal upright position and wash the burner with a high flow of water down into the slots, starting at the back and moving forward. Again,
ensure that no contact is made with the gaskets.
e. Use compressed air to clear excessive water from the burner after rinsing. Inspect the gasket.
(Minor surface tears are allowable. Major separations are not acceptable)

8)FAN ? The fan is probably coated with dust as well.
a. Place a towel at the bottom of the heat exchanger to cover the square port to the fan. This towel will catch all the dust blown in the next step.
b. Use compressed air to blow into the fan. It will rotate and dust will fly out of the fan housing into the towel above.

9)COMBUSTION CHAMBER ? Inspect the combustion chamber with a bright flashlight.
a. Remove the exhaust venting from top of the unit for the DV model
b. Place one towel at the bottom of the combustion chamber, protecting the discharge of the fan (fan port), as well as drape another towel covering the square opening of the combustion chamber (to prevent airborne debris)
c. Turn on the shop vacuum and vacuum all of the dirt from the combustion chamber.
d. At the same time, with the air compressor, blow air down through the top of the heat exchanger through the vent collar to remove additional contaminant.

10) HEAT EXCHANGER ? If there is a white, crusty solid buildup in the heat exchanger, please contact the Technical Service Department for further instruction.

11) SENSORS –
a. Clean the flame sensor and AFR with sandpaper, thoroughly to a bright finish. It is important to be very gentile with the sensor rods while cleaning them, as they will easily bend out of place. Their original position relative to the burner needs to be unaltered in order to function properly.

12) REASSEMBLE ? Reassemble the unit in reverse order. Key points to remember:
a. Inspect all of the gaskets.
b. Be aware of the black O?ring and mesh filter on the gas valve inlet.
c. Reconnect the plastic tube from the gas valve to the bottom of the combustion chamber.
d. Reattach all components that the manifold screws secure in their places.
e. Reconnect all wires to the computer board and any other clips.
f. Do not have any screws left over.

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