31
Sealed Combustion Chamber - GUD
(Qualified Servicer Only)
To inspect the combustion chamber at the start of each
heating season:
1. Shut off the electrical power and gas supply.
2. Looking through the observation window, check for
significant amounts of dirt, soot or debris.
3. If contaminates are present, remove the cover and
clean the chamber.
CAUTION
This furnace is equipped with a sealed
combustion chamber. It is mandatory to
replace all gaskets that are removed. Or-
der replacement gaskets prior to start-
ing service. Only a qualified servicer
should ever open the combustion cham-
ber.
Condensate Drainage System (Qualified
Servicer Only)
The drain tubes, standpipe, and field-supplied drain line
must be check annually and cleaned as often as neces-
sary to ensure proper condensate drainage.
Flue Passage (Qualified Servicer Only)
At the start of the heating season inspect and, if neces-
sary, clean the furnace flue passages.
Cleaning Flue Passages (Qualified
Servicer Only)
At the start of each heating season, inspect and, if
necessary, clean the furnace flue passages.
1. Turn off electrical power and the gas supply to the
furnace.
2. Remove the burner assembly by disconnecting the
gas line and removing the manifold brackets from
the partition panel.
3. Remove the collector box insulation and then re-
move the collector box from the partition panel.
4. Disconnect the PVC vent from the induced draft
blower so that the blower can be removed from the
recuperator coil cover.
5. Remove the recuperator coil cover and remove the
turbulators from the recuperator coil tubes.
6. The recuperator coil tubes can now be cleaned
using a long handled round wire brush, such as a
gun cleaning brush.
7. 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. Repeat for each tube.
8. When all heat exchanger tubes have been cleaned
and the residue removed with a vacuum, replace all
the parts in the reverse order in which they were
removed.
9. To reduce the chances of repeated fouling of the
heat exchanger, perform the checks listed in Start-
up and Adjustment, Section XIl.
Flame Sensor (Qualified Servicer Only)
Under some conditions, the fuel or air supply can create
a nearly invisible coating on the flame sensor. This
coating acts as an insulator, causing a drop in the flame
sensing signal. If this occurs, a qualified servicer must
carefully clean the flame sensor with emery cloth or
steel wool. After cleaning, the flame sensor output should
be as listed on the specification sheet.
Burners
WARNING
Electrical components are contained in
both compartments. To avoid electrical
shock, injury or death, do not remove
any internal compartment covers or at-
tempt any adjustment. Contact a quali-
fied service agent at once if an abnormal
flame appearance should develop.
Periodically during the heating season make a visual
check of the burner flames. Turn the furnace on at the
thermostat. Wait a few minutes, since any dislodged
dust will alter the normal flames appearance. Flames
should be stable, quiet, soft and blue with slightly or-
ange tips. They should not be yellow. They should
extend directly outward from the burner ports without
curling downward, floating or lifting off the ports.
