14
NOTE: After cleaning, the microamp signal should be in the
range listed in Specification Sheet.
Burner
Assembly
Pilot
Tube
Flame Sensor
Ignitor
Figure 16
Ignitor and Flame Sensor
FLUE PASSAGES (QUALIFIED SERVICER ONLY)
At the start of each heating season, inspect and, if neces-
sary, clean the unit flue passage.
CLEANING FLUE PASSAGES (QUALIFIED SERVICER
ONLY)
1. Shut off electric power and gas supply to the unit.
2. Remove burner assembly by disconnecting the gas line
and removing the manifold brackets from the partition
panel.
3. Remove the flue from the induced draft blower and the
collector box from the partition panel.
4. The primary heat exchanger tubes can be cleaned using
a round wire brush attached to a length of high grade
stainless steel cable, such as drain cleanout cable.
Attach a variable speed reversible drill to the other end
of the spring cable. Slowly rotate the cable with the drill
and insert it into one of the primary heat exchanger
tubes. While reversing the drill, work the cable in and out
several times to obtain sufficient cleaning. Use a large
cable for the large tube, and then repeat the operation
with a small cable for the smaller tube. Repeat for each
tube.
5. When all heat exchanger tubes have been cleaned,
replace the parts in the reverse order in which they were
removed.
6. To reduce the chances of repeated fouling of the heat
exchanger, perform the steps listed in “Start-up and
Adjustment”.
MAIN BURNER FLAME (QUALIFIED SERVICER ONLY)
Flames should be stable, soft and blue (dust may cause
orange tips but must not be yellow). The flames must extend
directly outward from the burner without curling, floating or
lifting off (Figure 17).
Check the burner flames for:
1. Good adjustment
2. Stable, soft and blue
3. Not curling, floating, or lifting off.
Figure 17
Burner Flame
WARNING
To avoid death or personal injury due to
electrical shock, do not remove any internal
compartment covers or attempt any
adjustment. Contact a qualified servicer at
once if an abnormal flame appearance
should develop.
At least once a year, prior to or during the heating season,
make a visual check of the burner flames.
NOTE: This will involve removing and reinstalling the heat
exchanger door on the unit, which is held by several screws.
If you are uncertain about your ability to do this, contact a
qualified servicer.
If a strong wind is blowing, it may alter the airflow pattern
within the unit enough that an inspection of the burner
flames is not possible.
CLEANING OF BURNERS
1. Shut off electric power and gas supply to the unit.
2. Remove the screws holding the burner retention bracket
in place.
3. Remove the burners.
4. Use a bottle brush to clean burner insert and inside of the
burners.
5. Replace burners and burner retention bracket, inspect
the burner assembly for proper seating of burners in
retention slots.
6. Reconnect electrical power and gas supply.
CAUTION
Label all wires prior to disconnection when
servicing controls. Wiring errors can cause
improper and dangerous operation.
CAUTION
Verify proper operation after servicing.
For further information on the yearly inspection, consult the
User Manual. It is recommended that a qualified servicer
inspect and service the unit at least once each year.