A.O. Smith 110 Troubleshooting Manual - page 28
Troubleshooting Guide
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Page
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 contaminants.
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.
Figure 29
Figure 30