MORTEX
PRODUCTS
INC
501
TERMINAL
RD
FORT
WORTH,
TX
76106
Page
20
Mortex has a 7” Outer Pipe and a 4” Inner Pipe.
Using a Coleman or Nordyne Roof Jack on a Mortex
Furnace will cause vented combustion products to get drawn
into the combustion air causing the flame to extinguish
within 10 seconds because the flame is running out of
oxygen.
These instructions list the maximum vent gas temperature. This
temperature must be used to select the appropriate venting
clearances.
It is recommended that the appliance is installed in a location
where the space temperature is 32 °F (0°C) or higher. If the
appliance is installed in a location where the ambient
temperature is below 32 °F (0°C), the combustion by-products
could condense causing damage to the appliance heat
exchanger.
IMPORTANT:
The “ROOF JACK VENT SYSTEM” must be
installed as specified in these instructions for Manufactured and
Modular Homes.
This appliance
cannot be
common vented with another gas
appliance.
Combustion air
cannot be supplied
from occupied spaces. The
Mortex roof jack vent system
must be used
with this furnace.
Approved Manufactured (Mobile) Homes and Modular Homes
must be vented with an approved roof jack that consists of a 4”
diameter vent pipe and a 7” diameter outer pipe only.
Do not
use a roof jack provided by any other manufacturer.
VENTING
Category I roof jack direct venting consists of vertically venting
one appliance in roof jack vent using two single wall metal
pipes and a crown assembly.
The roof jack type vent system extends in a general vertical
direction and does not contain offsets. A vent system having any
offset is not permitted.
The vent system consists of a four inch (4”) inner pipe attached
to the flue collar (4” collar) on the top of the heat exchanger just
below the top of the furnace and an outer seven inch (7”) pipe.
The combustion air is drawn between the inner four inch (4”)
pipe and the outer seven inch (7”) pipe. The seven inch (7”) pipe
is attached to a flange in the top cover and must be secured to
the top cover with a minimum of two (2) mechanical fasteners,
such as screws or rivets.
Figure 20: Roof Jack Mounting Collars – Top of Furnace
VENTING INTO AN EXISTING ROOF JACK
The furnace shall not be connected to another manufacturers
factory built roof jack vent system. If the furnace is connected to
another manufacturer’s roof jack vent system the furnace will
not vent properly especially if the existing roof jack consists of
larger diameter pipes.
Installing the correct roof jack is required. The installer must
change the roof jack vent system when installing a new furnace
or replacing an existing furnace.
ROOF JACK EXTENSIONS AND CROWN ASSEMBLY
1.
The roof jack extensions and the crown assembly must be
installed in accordance with nationally recognized building
codes or standards and /or these instructions.
2.
The roof jack has optional indoor and outdoor extensions.
The outdoor extensions must be used to extend the crown
assembly above the snow line.
3.
The indoor extensions, shown in Figure 21, are 7 inches in
dia (Left Pipe) and 4 inches in dia (Right Pipe). The 4 inch
dia pipe is placed inside the 7 inch dia pipe. The extensions
are used when the roof jack is too short to extend to the
furnace. The extensions are available in a 10 inch length
and a 31 inch length. Refer to accessories parts list in the
Service and Maintenance Manual.
Figure 21: Roof Jack Indoor Extension Pipes
4.
The outdoor extension, shown in Figure 22 has a 4 inch dia
pipe is fastened to the inside the 7 inch dia pipe. The
extension is used when the roof jack crown assembly must
be extended because of snow line, the roof peak or other
obstructions. The extension is available in a 16 inch length.
Refer to accessories parts list in the Service and
Maintenance Manual.
Figure 22: Roof Jack Outdoor Extension Pipes
5.
The roof jack crown assembly must extend at least three (3)
ft (0.91 cm) above the highest point where it passes through
a roof of a building and at least two (2) feet higher than any
Venting into another manufacturers roof jack vent system
that is equipped with larger diameter vent and combustion
air pipes will cause combustion products being vented to be
drawn into the combustion air. This will result in a reduced
amount of oxygen to the burner flame and will cause the
flame to extinguish within the first 5 to 15 seconds or less.
