Sears 9MPD - Manual (Page 26)

NOTE: All gaskets and seals must be in place for sealed combus­
tion applications.
Ensure that the vent fitting is securely attached to the combustion
blower using the rubber coupling and clamps.
Connect the PVC vent extension pipe to the vent fitting. This pipe
has a built-in channel to assist vent condensate disposal.
Align the arrow on the PVC pipe with the airflow marking arrow on
the vent fitting. See label on the PVC pipe for proper installation.
This pipe may only be shortened if an elbow is used to connect the
PVC vent extension tube to field-installed vent pipe. Securely at­
tach the PVC vent extension pipe to the vent fitting with the clamp.
This configuration allows left side venting from the furnace. If right
side venting is required, the combustion blower must be relocated
on the plastic transition box. Loosen the four{4) screws that se­
cure the blower to the transition approximately V
2
". Rotate the
blower 180° and secure with the four(4) screws. Note that some
combustion blowers have plastic spacers on the mounting legs of
the blower located at the
6
and
1 2
o'clock positions {blower snout
to the left or right) that are required for proper fit up of the blower to
the transition. Use caution to not over tighten the screws to pre­
vent stripping out of the plastic mounting holes.
NOTE: The vent fitting MUST be installed with the airflow marking
arrow pointed toward the vent pipe, with the drain stub at a 5° to
1 0
° downward slope.
Plug the upper drain stub on the vent fitting with the yellow plastic
cap.
Connect the PVC vent extension pipe to the vent fitting. This pipe
has a built-in channel to assist vent condensate disposal.
Align the arrow on the PVC pipe with the airflow marking arrow on
the vent fitting. See label on the PVC pipe for proper installation.
This pipe may only be shortened if an elbow is used to connect the
PVC vent extension tube to field-installed vent pipe. Securely at­
tach the PVC vent extension pipe to the vent fitting with the clamp.
Remove the pressure switch hose from the upper stub on the
plastic transition box.
Relocate the plastic caps on the stubs of the plastic transition box
from the lower stubs to the upper stubs and secure tightly with the
clamps.
Route the pressure switch hose to the lower stub on the plastic
transition box. Cut off excess hose and discard. Connect the pres­
sure switch hose to the lower stub on the plastic transition box.
NOTE: Failure to correctly install the pressure switch hose to the
transition box can adversely affect the safety control operation.
Connect the ^/
4
' OD rubber hose with the 90° bend to the drain
stub on the bottom of the plastic transition box and secure with a
^ / 4
' clamp.
Route the hose to the large drain stub on the condensate trap. Cut
off excess hose and discard. Connect the hose to the drain stub
on the transition and secure with a
^ / 4
' clamp.
Connect the %' OD rubber hose with the 90° bend to the left
drain stub on the vent fitting and secure with a clamp.
Route the hose to the smaller stub on the condensate trap. Cut off
excess hose and discard. Connect the hose to the drain stub on
the trap and secure with a clamp.
For left side or right side mounted condensate trap, the pres­
sure tap on the condensate trap MUST be connected to the un­
used pressure tap located on the top of the plastic transition box.
Remove the plastic ca ps from the pressure ta p on the condensate
trap and the plastic transition and connect the OD rubber
hose. {See
Figure 17)
NOTE: Route hoses to the condensate trap with no kinking or
binding for proper condensate drainage.
Connecting Vent and Combustion Air Piping
A 1A#ARI\III\IB
CARBON MONOXIDE POISONING HAZARD
Failure to properly seal vent piping can result in death,
personal injury and/or property damage.
Cement or mechanically seal all joints, fittings, etc. to
prevent leakage of flue gases.
Refer to the Figure 8 through Figure 17 that corresponds to the
installation position of the furnace for the application.
Preassemble the vent and combustion air piping from the furnace
to the vent termination. Do not cement the pipejoints until the pipe
preassembly process is complete.
Combustion Air Pipe Connection
(Dual Certified or
Direct Vent)
Install the air intake coupling and gasket to the furnace with the
four(4) screws.
Note: The air intake coupling and gasket can be installed to the
top panel to the alternate air intake locations on either the left or
right side panels of the furnace.
For downflow installation, the air intake coupling and gasket must
be installed to the alternate air intake location on either the left or
right side panels. Remove the3' hole plug from the side panel and
relocate to the air intake hole in the top panel. Use four screws to
seal the four{4) mounting holes in the top panel next to the hole
plug. Drill four{4) ^/
5 4
' diameter holes in the casing using the air
intake coupling as the template.
The air intake coupling is sized for 2" PVC pipe.
Install the combustion air pipe to the air intake coupling using RTV
sealant to provide for future serviceability.
Vent Pipe Connection
Install the vent pipe grommet to the furnace panel. Locate the
grommet in the furnace panel at a location directly away from the
vent fitting on the combustion blower. The grommet snaps intothe
3' hole plug from the furnace panel. NOTE: Depending on the
installation position, the vent pipe grommet will be installed to the
top panel or to the alternate location on the side panels. If needed,
remove the 3 ' hole plug from the furnace panel and relocate to the
open hole in the furnace panel. {See
Figure 12 or Figure 17)
Install the vent pipe to the rubber coupling, the vent fitting or the
PVC vent extension pipe. Securely attach using the clamp or PVC
cement as required.
Note: The vent fitting MUST be installed with the air flow
marking arrow pointed toward the vent pipe. (See Figure 18)
Some installations require the vent fitting to be installed with
a 5° to 10° downward slope. (See Figures 8 - 1 7 )
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