11
VI. CATEGORY I VENTING (VERTICAL VENTING)
WARNING
T
O PREVENT POSSIBLE PERSONAL INJURY OR DEATH DUE TO ASPHYXIATION,
THIS FURNACE MUST BE
C
ATEGORY
I
VENTED.
D
O NOT VENT USING
C
ATEGORY
III
VENTING.
Category I Venting is venting at a non-positive pressure. A furnace
vented as Category I is considered a fan-assisted appliance
and the vent system does not have to be “gas tight.”
NOTE:
Gas
furnaces with induced draft blowers draw products of combustion
through a heat exchanger allowing, in some instances, common
venting with natural draft appliances (i.e. water heaters).
All installations must be vented in accordance with National Fuel
Gas Code NFPA 54/ANSI Z223.1 - latest edition. In Canada, the
furnaces must be vented in accordance with the National
Standard of Canada, CAN/CSA B149.1 and CAN/CSA B149.2 -
latest editions and amendments.
NOTE:
The vertical height of the Category I venting system must
be at least as great as the horizontal length of the venting system.
WARNING
T
O PREVENT POSSIBLE PERSONAL INJURY OR DEATH DUE TO ASPHYXIATION,
COMMON VENTING WITH OTHER MANUFACTURER'S INDUCED DRAFT APPLIANCS
IS NOT ALLOWED.
The minimum vent diameter for the Category I venting system is
as shown below:
UPFLOW
COUNTERFLOW
70
4 Inch
4 Inch
90
4 Inch
4 Inch
115
N/A
4 Inch
140
N/A
N/A
MODEL
MINIMUM VENT
Under some conditions, larger vents than those shown above
may be required or allowed.
When an existing furnace is removed from a venting system
serving other appliances
, the venting system may be too large to
properly vent the remaining attached appliances.
Upflow or Horizontal units
are shipped with the induced draft
blower discharging from the top of the furnace. (“Top” is as
viewed for an upflow installation.) The induced draft blower can
be rotated 90 degrees for Category I venting (Figure 3). For
horizontal installations, a four inch single wall pipe can be used
to extend the induced draft blower outlet 1/2” beyond the furnace
cabinet. Vent the furnace in accordance with the National Fuel
Gas Code NFPA 54/ANSI Z223.1 - latest edition. In Canada, vent
the furnace in accordance with the National Standard of Canada,
CAN/CSA B149.1 and CAN/CSA B149.2 - latest editions and
amendments.
Venting
THIS FURNACE IS NOT DESIGN CERTIFIED TO BE
HORIZONTALLY VENTED.
Supply
Air
Upflow Rotated Induced Draft Blower
To rotate the induced draft blwer counterclockwise, proceed as
follows:
1. Disconnect electrical power from the furnace.
2. Disconnect the induced draft blower power leads, flue
pipe, and pressure switch tubing.
3. Remove the round cutout from the appropriate side of the
furnace.
4. Remove and save the four screws that hold the induced
draft blower to the flue collector box.
5. Turn the induced draft blower 90 degrees clockwise, or
counterclockwise. The gasket is adhered to the back
plate and will rotate with the blower assembly.
6. Reinstall the induced draft blower on the flue collector
box, using the four screws removed in Step 3. Tighten
screws to provide an airtight seal.
7. Reconnect the induced draft blower power leads. NOTE:
If the wires are not long enough, pull extra wire from the
wire bundle in the blower compartment.
8. Remove and save the screw that holds the pressure
switch to the furnace top panel.
9. Relocate the pressure switch to the same side as the
flue outlet in the hole provided.
10. Reconnect the draft blower power leads, flue pipe, and
pressure switch tubing. Make sure that all wires and the
pressure switch tubing are at least one inch from the flue
pipe, or any other hot surfaces.
11. Restore power to the furnace.
Counterflow units
are shipped with the induced draft blower
discharging from the top of the furnace. (“Top” as viewed for a
counterflow installation.) Vent the furnace in accordance with the
National Fuel Gas Code NFPA 54/ANSIZ223.1 - latest edition. In
Canada, vent the furnace in accordance with the National
Standard of Canda, CAN/CSA B149.1 and CAN/CSA B149.2 -
latest editions and amendments.
WARNING
N
EVER ALLOW THE PRODUCTS OF COMBUSTION, INCLUDING CARBON
MONOXIDE, TO ENTER THE RETURN DUCTWORK OR CIRCULATION AIR SUPPLY.
VII. EXTERIOR MASONRY CHIMNEYS
CATEGORY I FURNACES ONLY
An exterior masonry chimney is defined as a “Masonry chimney
exposed to the outdoors on one or more sides below the roof
line.” The ability to use a clay lined masonry chimney depends
on a parameter not associated with interior chimneys. This
variable is the geographic location of the installation.
