Vent Couplings; Upfl Ow Furnaces; Downfl Ow Furnaces; Alternate Vent Pipe Installation - Nordyne M4RC Upflow Installation Instructions Manual

(914098) or VentilAire™ IV (914229) fresh air supply
system. Alternate means for providing ventilation air
must meet the requirements of all applicable local and
federal codes.
For downfl ow models, a special mounting bracket is
supplied with the furnace for installation of the VentilAire™
supply air system. The bracket is installed on the right
hand side at the top of the cabinet, as shown in Figure
31. The bracket can be secured to the unit using the self-
drilling screws supplied with the kit. Please follow the
instructions provided with the kit.
For upfl ow models, the means for providing the required
ventilation must be incorporated into the upfl ow furnace
base or the return air ductwork to the furnace.
Vent Couplings (Figure 32)
M4 series furnaces require couplings to be installed over
the combustion air fi nish fl ange and where the vent pipe
exits the furnace cabinet. NOTE: These couplings are not
supplied in the *RL extra parts bag
• Each coupling must be secured to the fi nish fl ange
or vent pipe with a hose clamp (if using neoprene
couplings).
• Upfl ow furnaces require the 3" neoprene coupling
clamps to be installed above the coil box.
Upfl ow Furnaces:
Combustion air and exhaust vent piping must have
removable connections between the furnace fl anges and
vent pipes when installed vertically in front of the coil box.
NOTE: Both vent pipes must be long enough to clear the
height of the coil box when installed. This allows for future
servicing or maintenance of the coil.
Position the 2" x 3" neoprene coupling between the top of
the 2" vent pipe and the 3" vent pipe. Secure both ends
of the couplings with hose clamps, ensuring that the
connection is tight and leak free.
3" PVC Pipes
3" Neoprene
Couplings
Coil Box
2" x 3"
Neoprene
Couplings
UPFLOW FURNACE
Figure 32. Vent Couplings
3" PVC Pipes
3" PVC
2" x 3"
Pipes
Neoprene
Couplings
DOWNFLOW FURNACE
Downfl ow Furnaces
Since there is no coil box above the furnace, both 3" vent
pipes can be run vertically for the entire length of the
pipes from the 2" x 3" coupling to the outdoors. Secure
both ends of the couplings, ensuring that the connection
is tight and leak free.

Alternate Vent Pipe Installation

When running the 2" PVC pipe out through the top of the
*RC upfl ow furnace, there may be possible clearance
issues when transitioning the PVC pipe from 2" to 3".
• To increase the size of the PVC fl ue from 2" to 3",
you may use two, 2" x 45° PVC elbows to achieve the
clearances needed between the coil box and the 2" x
3" neoprene coupling. See Figure 33.
• Install the 2" x 3" neoprene coupling in the vertical run
only. If the coupling is installed horizontally, it will allow
water to build up inside the furnace and cause a lock
out condition.
3" vent pipes
2" x 3"
Neoprene
Couplings
Coil Box
2" Neoprene
Couplings
Figure 33. Alternate vent Pipe Installation
2" PVC
Pipe
2" x 45 0 PVC
Elbow
23