7
UNIT DAMAGE HAZARD
Failure to follow this caution may result in furnace
component damage.
Label all wires prior to disconnection when servicing
controls. Wiring errors can cause improper and hazardous
operation.
CAUTION
!
3. Disconnect wires or connectors to flame rollout switch, gas
valve, igniter, and flame sensor.
4. Disconnect combustion--air intake pipe from intake hous-
ing.
5. Remove the pressure switch tube from intake housing.
6. Remove screws attaching intake housing to burner box, and
rotate intake housing away from burner box for removal.
7. Using backup wrench, disconnect gas supply pipe from fur-
nace gas control valve.
8. Disconnect pressure tubing from gas valve.
9. Remove two screws attaching top filler panel and rotate up-
wards to gain access to screws attaching burner box to cell
panel.
10. Remove screws attaching burner box to cell panel. (See Fig.
6.)
NOTE
: Burner box, cover, manifold, gas valve, and burner
assembly should be removed as one assembly.
11. Clean heat exchanger openings with a vacuum and a soft
brush. (See Fig. 8.)
NOTE
: After cleaning, inspect the heat exchangers to ensure they
are free of all foreign objects that may restrict flow of combustion
products.
PRIMARY HX
INLET OPENINGS
A96305
Fig. 8 -- Cleaning Inlet Openings of Primary
Heat Exchangers
UNIT MAY NOT OPERATE
Failure to follow this caution may result in improper or
intermittent unit operation.
The ground wire from the gas valve MUST be attached to
the burner box attachment screw.
CAUTION
!
12. Reverse items 3 through 10 for reassembly.
NOTE
: Be sure burner box gasket is installed between burner box
and cell panel. (See Fig. 6.) If gasket is damaged, replace it.
NOTE
: Inspect combustion--air intake housing. If foamed gasket
was removed, check for any damage. If gasket is damaged in any
way, it must be repaired. To repair, remove damaged gasket
section, apply sealant releasing agent such as PAM cooking spray
or equivalent (must not contain corn nor canola oil, halogenated
hydrocarbons nor aromatic content, to prevent inadequate seal
from occurring) to burner box and apply a small bead of G.E. RTV
162, G.E. RTV 6702, or Dow--Corning RTV 738 sealant to edge
of combustion--air intake housing. (See Fig. 9.)
PAM
RTV
A93087
Fig. 9 -- Combustion--Air Intake Housing
Gasket Repair
13. Refer to furnace wiring diagram and reconnect wires to
flame rollout switch, gas valve, igniter, and flame sensor.
14. Reconnect pressure switch tubes to gas valve and intake
housing. Refer to tube routing label on main furnace door
for proper tube location. (See Fig. 10.) Be sure tubes are not
kinked.
15. Turn on gas and electrical supplies to furnace.
16. Check furnace operation through two complete heat operat-
ing cycles. Look through sight glass in burner enclosure to
check burners. Burner flames should be clear blue, almost
transparent. (See Fig. 11.)
17. Check for gas leaks.
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death or property damage.
Never test for gas leaks with an open flame. Use a
commercially available soap solution made specifically
for the detection of leaks to check all connections.
!
WARNING
18. Replace main furnace door.
Secondary Heat Exchangers
NOTE
:
The condensing side (inside) of the secondary heat
exchangers CANNOT be serviced or inspected. A small number of
bottom outlet openings can be inspected by removing the inducer
assembly. See Flushing Collector Box and Drainage System
section for details on removing inducer assembly.
Step 5 — Flushing Collector Box and Drainage
System
1. Turn off gas and electrical supplies to furnace.
2. Remove main furnace door.
3. Disconnect inducer motor and pressure switch wires or con-
nectors.
PG
9M
AB
