# 47860A005
Page 10
Upflow Direct Vent Installation
An inlet air restrictor plate (see Figure 2 on page 5) is supplied
with this furnace and can be found in the plastic bag containing
these Installation Instructions and the User’s Information Manual.
This restrictor plate is to be used only in non-direct vent
applications.
See the non-direct venting sections on pages 11
and 13 for more information on installing the restrictor plate in
non-direct vent applications.
The flue pipe screen (see Figure 2 on page 5) should be
installed at the termination of the flue pipe and is designed
to keep objects out of the flue pipe. An additional screen
should
not
be placed in the intake termination. If a screen
is installed, the air intake may freeze shut.
For horizontal venting, refer to Figure 7. For vertical venting,
refer to Figure 8. It is permissible to run the vent vertically
through the roof and terminate it as shown in Figure 8, and
to run the combustion air intake pipe horizontally through a
side wall and terminate as shown in Figure 7. The vent pipe
on horizontal runs must slope upward, away from the
furnace, at a minimum pitch of 1/4" per foot of run, to prevent
accumulation of condensate.
Do not cement air intake into the connector on burner
box. Use high temperature RTV silicone sealant so
intake pipe can be removed if service is required.
In horizontal venting applications, the vent and air
intake pipe must be installed on the same side of the
house within the parameters shown in Figure 7.
Prime the trap system by slowly pouring 1 cup of water down
the vent pipe. On initial start-up of the unit, some of the
water used to prime the trap system may run down into the
combustion blower and cause noise.
Upflow Direct Vent – Vertical Venting
Figure 8
Figure 7
Upflow Direct Vent – Horizontal Venting
* The 18" dimension is the minimum
recommended height for ex-
tremely cold areas. In these areas,
moisture in the flue gases may
condense and freeze on the air
intake if this height is reduced. In
milder climates, this may be
reduced to a minimum of 6".
Height may be increased as
needed provided total length is not
exceeded.
THIS PIECE
IS OPTIONAL.
INTAKE PIPE
FLUE PIPE
3” MIN. - 48” MAX.
Overhead View
