Cleaning Heat Exchangers - Carrier Deluxe 58MVB Service And Maintenance Instructions

15. Reinsert the igniter wires in the slot in the manifold grom-
met, dressing the wires to ensure there is no tension on the
igniter itself. (See Fig. 7.)
WARNING
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
Igniter wires must be securely placed in slot in manifold
grommet or else they could become pinched or severed
and electrically shorted.
16. Reconnect wires to gas valve and igniter. Refer to furnace
wiring diagram for proper wire location.
17. Reinstall burner box pressure tube to gas valve regulator
fitting.
18. Reinstall gas supply pipe to furnace gas control valve us-
ing backup wrench on gas valve to prevent rotation and
improper orientation.
NOTE: Use propane gas resistant pipe dope to prevent gas leaks.
DO NOT use Teflon tape.
WARNING
!
FIRE, EXPLOSION, UNIT DAMAGE HAZARD
Failure to follow this warning could result in personal
injury, death, or property damage.
Gas valve switch MUST be facing forward or tilted
slightly.
19. Replace burner box cover.
20. Turn on gas and electrical supplies to furnace.
21. Check for gas leaks.
WARNING
!
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.
22. Replace main furnace door.
Step 4—Cleaning Heat Exchangers
The following items should be performed by a qualified service
technician.
PRIMARY HEAT EXCHANGERS
If the heat exchangers get an accumulation of light dirt or dust on
the inside, they may be cleaned by the following procedure:
NOTE: If the heat exchangers get a heavy accumulation of soot
and carbon, both the primary and secondary heat exchangers
should be replaced rather than trying to clean them thoroughly
due to their intricate design. A build- -up of soot and carbon
indicates that a problem exists which needs to be corrected, such
as improper adjustment of manifold pressure, insufficient or poor
quality combustion air, improper vent termination, incorrect size
or damaged manifold orifice(s), improper gas, or a restricted heat
exchanger (primary or secondary). Action must be taken to
correct the problem.
1. Turn off gas and electrical supplies to furnace.
2. Remove main furnace door.
CAUTION
!
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.
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 re-
moval.
7. Using backup wrench, disconnect gas supply pipe from
furnace gas control valve.
8. Disconnect pressure tubing from gas valve.
9. Remove 2 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 1 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.
12. Reverse items 4 through 10 for reassembly.
PRIMARY HX
INLET OPENINGS
Fig. 8 --- Cleaning Inlet Openings of Primary
Heat Exchangers
6
A96305