3
away from the furnace. Support the vent pipe as close to the
furnace as possible to prevent damage to the vent system.
NOTE
: If the vent pipe passes through the vent pipe coupling into
the vent elbow on the inducer, it may be necessary to cut the vent
pipe external to the casing, then re--cement the vent pipe with a
field--supplied coupling.
1. Support the vent pipe as close to the furnace as possible to
prevent damage to the vent system.
2. Cut vent pipe with a hacksaw and move the remaining vent
pipe out of the way. Secure the vent pipe if necessary.
3. Loosen both clamps at the vent pipe support attached to
furnace casing.
4. Loosen clamp for the vent pipe at vent elbow on the inducer
assembly.
5. Remove remaining vent pipe through the top of the furnace
casing and set aside.
ELECTRICAL OPERATION HAZARD
Failure to follow this caution may result in improper
furnace operation or failure of furnace.
Label all wires prior to disconnection when servicing
controls. Wiring errors can cause improper and dangerous
operation.
CAUTION
!
D’EQUIPEMENT D’OPERATION
Toute erreur de câblage peut être une source de danger et de
panne.
Lors des opérations d’entretien des commandes, étiqueter
tous les fils avant de les déconnecter.
PRUDENCE
!
Pressure Switch Removal
NOTE
: There are two types of pressure switches. The modulating
pressure switch assembly has three pressure switches. Two are
side-by-side with the third switch mounted to the back of one of
the switches.
All other furnaces have two pressure switches mounted
back-to-back.
Pressure switches for PSC inducers have a tube on the back
pressure switch that connects to the port on the inducer assembly.
Pressure switches for the modulating inducers only have one
pressure switch tube.
1. Remove the front pressure switch tube from the port on the
collector box. See Fig. 2.
2. Disconnect the pressure switch harness (modulating only)
from the main wiring harness or remove the individual
wires from the front pressure switch (non--modulating).
Note the location of the wires for reassembly.
3. Remove the screws that attach the pressure switch assembly
to the inducer.
4. Remove the back pressure switch tube that connects to the
inducer assembly (PSC only).
5. Remove the wires from the back pressure switch. Note the
location of the wires for reassembly. (PSC only).
6. Set the pressure switches aside.
7. If the relief tube for the condensate trap is routed across the
inducer assembly, remove the tube from the port on the
collector box and from the stand--offs on the inducer and
move the tube aside
Inducer Mounting Screw
Pressure Switch
Inducer Mounting Screw
Remove Vent Elbow
Vent Elbow Clamp
Remove Tube(s) from
Standoffs
Inducer Mounting Screw
Inducer Mounting Screw
Pressure Switch
Mounting Screw
A11361
Fig. 2 -- Inducer Assembly
Inducer Assembly Removal
1. Remove the door bracket from the front edge of the blower
shelf.
2. Remove the wires that connect the main wiring harness to
the inducer motor harness. On furnace using an old style
ECM inducer, remove the adapter harness between the in-
ducer motor and main furnace wiring harness and discard.
See Fig. 1 and 3.
Disconnect from
ECM Motor
Disconnect from
furnace wiring harness
Disconnect from
furnace wiring harness
A12001
Fig. 3 -- ECM Adapter Harness
3. Remove the screws from the tabs on inducer assembly that
secures the inducer to the collector box. Note there is one
mounting tab directly under the vent elbow.
4. Remove the inducer assembly and set aside.
5. To avoid double gasketing and leakage, check to make sure
the drain gaskets for the inducer and the inducer gasket are
not still attached to the collector box.
6. Remove any adhered gaskets from the front of the collector
box.
7. Remove the vent elbow from the inducer assembly and set
aside.
Inducer Inlet Choke Plate (PSC inducers only)
NOTE
:
Some PSC inducers have a factory--installed Inducer Inlet
Choke. The Inlet Choke snaps into the inlet of the Inducer Assembly.
A new Choke Plate is included in the loose parts bag of the inducer kit.
If a new Choke Plate is required as shown in Table 3 and is not in-
cluded in the loose parts bag, the choke plate from the old inducer as-
sembly can be re--used in the new assembly. Modulating inducer as-
semblies do not use an Inlet Choke Plate. See Fig
.
4.
1. Un--snap the Inlet Choke from the old inducer assembly.
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