Carrier 59MN7B Installation, Start-Up, Operating And Service And Maintenance Instructions page 87

WARNING
!
ELECTRICAL SHOCK, FIRE OR EXPLOSION
HAZARD
Failure to follow this warning could result in personal
injury or death, or property damage.
Before installing, modifying, or servicing system, main
electrical disconnect switch must be in the OFF position and
install a lockout tag. There may be more than one
disconnect switch. Lock out and tag switch with a suitable
warning label. Verify proper operation after servicing.
Always reinstall access doors after completing service and
maintenance.
WARNING
!
ELECTRICAL SHOCK AND FIRE HAZARD
Failure to follow this warning could result in personal injury,
death, and/or property damage.
Turn off the gas and electrical supplies to the furnace and
install lockout tag before performing any maintenance or
service. Follow the operating instructions on the label
attached to the furnace.
2. Remove control door.
3. Disconnect wires or connectors to flame rollout switch, gas
valve, igniter, and flame sensor.
4. Using backup wrench, disconnect gas supply pipe from fur-
nace gas control valve.
5. Remove two screws attaching top filler plate and rotate up-
wards to gain access to screws attaching burner assembly to
cell panel.
6. Remove screws attaching burner assembly to cell panel.
See Fig. 67.
NOTE: Burner cover, manifold, gas valve, and burner assembly
should be removed as one assembly.
7. Clean heat exchanger openings with a vacuum and a soft
brush. See Fig. 70.
NOTE: After cleaning, inspect the heat exchangers to ensure they
are free of all foreign objects that may restrict flow of combustion
products.
8. Reverse items 6 through 1 for reassembly.
9. Refer to furnace wiring diagram and reconnect wires to
flame rollout switch, gas valve, igniter, and flame sensor.
10. Turn on gas and electrical supplies to furnace.
11. Check furnace operation through 2 complete heat operating
cycles. Look at burners. Burner flames should be clear blue,
almost transparent. See Fig. 62.
12. Check for gas leaks.
Fig. 70 - - Cleaning Heat Exchanger Cell
! WARNING
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Never purge a gas line into a combustion chamber. 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. A fire or explosion may
result causing property damage, personal injury or loss of
life.
13. Replace main furnace door.
Secondary Heat Exchangers
The condensing side (inside) of the secondary heat exchanger
CANNOT be serviced or inspected without complete removal of
the heat exchanger assembly. Detailed information on heat
exchanger removal can be obtained from your Distributor.
Wiring Diagrams
See Fig. 72 for the Deluxe 4- -Way Multipoise Furnace wiring
diagrams.
WINTERIZATION
CAUTION
!
UNIT AND PROPERTY DAMAGE HAZARD
Failure to follow this caution may result in unit component or
property damage.
If the furnace is installed in an unconditioned space where the
ambient temperatures may be 32_ F (0_ C) or lower, freeze
protection measures must be taken to prevent property or
product damage.
Since the furnace uses a condensing heat exchanger, some water
will accumulate in the unit as a result of the heat transfer process.
Therefore, once it has been operated, it cannot be turned off and
left off for an extended period of time when temperatures will
reach 32_F (0_C) or lower unless winterized. Follow these
procedures to winterize your furnace:
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A11273