3
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 or Pressure Transducer Tube
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.
The Ultra Low NOx furnace uses a pressure transducer mounted to
the heat exchanger cell panel instead of a pressure switch. It is not
necessary to remove the pressure transducer when replacing the
inducer assembly.
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. The pressure transducer for the Ultra Low
NOx model is not connected to the inducer assembly
.
1. Remove the front pressure switch or pressure transducer
tube from the port on the collector box. See Fig. 2. For
Utlra Low NOx models, go to Step 7. all other models,
continue with Step 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 or pressure
transducer tube 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
Representative drawing only, some models may vary.
A11361
Fig. 2 -- Inducer Assembly with Pressure Switches.
(Modulating/Ultra Low NOx model is similar)
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 and Ultra Low
NOx inducers only)
NOTE
:
Some PSC and Ultra Low NOx inducers have a factory--in-
stalled 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 included in the loose parts bag, the choke plate from
the old inducer assembly can be re--used in the new assembly. Modu-
lating inducer assemblies do not use an Inlet Choke Plate. See Fig
.
4.
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