SYSTEM OPERATION
10
POSITION*
SIDES
REAR
FRONT BOTTOM
FLUE
TOP
Counterflow
0"
0"
3"
NC
0"
1"
Horizontal
6"
0"
3"
C
0"
6"
C = If placed on combustible floor, floor MUST be wood only.
NC = For installation on non-combustible floors only. A combustible subbase
must be used for installations on combustible flooring.
*CVM97 MINIMUM CLEARANCES TO COMBUSTIBLE MATERIALS
(INCHES)
TOP
BOTTOM
TOP
BOTTOM
Counterflow
Figure 1
CLEARANCES AND ACCESSIBILITY
NOTES
:
•
For servicing or cleaning, a 24” front clearance is re
-
quired.
•
Unit connections (electrical, flue and drain) may neces
-
sitate greater clearances than the minimum clearances
listed above.
•
In all cases, accessibility clearance must take pre
-
cedence over clearances from the enclosure where
accessibility clearances are greater.
Installations must adhere to the clearances to combustible
materials to which this furnace has been design certified. The
minimum clearance information for this furnace is provided
on the unit’s clearance label. These clearances must be per
-
manently maintained. Clearances must also accommodate
an installation’s gas, electrical, and drain trap and drain line
connections. If the alternate combustion air intake or vent/flue
connections are used additional clearance must be provided
to accommodate these connections. Refer to
Vent/Flue Pipe
and Combustion Air Pipe
for details.
NOTE:
In addition to the required clearances to combustible
materials, a minimum of 24 inches service clearance must
be available in front of the unit.
A furnace installed in a confined space (i.e., a closet or utility
room) must have two ventilation openings with a total min
-
imum free area of 0.25 square inches per 1,000 BTU/hr of
furnace input rating. Refer to Specification Sheet applicable to
your model for minimum clearances to combustible surfaces.
One of the ventilation openings must be within 12 inches of
the top; the other opening must be within 12 inches of the
bottom of the confined space. In a typical construction, the
clearance between the door and door frame is usually ade
-
quate to satisfy this ventilation requirement.
EXISTING FURNACE REMOVAL
NOTE:
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.
The following vent testing procedure is repro duced from
the
American National Standard / National Standard of
Canada for Gas-Fired Central Furnaces ANSI Z21.47,
CSA-2.3 latest edition Section 1.23.1.
The following steps shall be followed with each appliance
connected to the venting system placed in operation, while
any other appliances connected to the venting system are
not in operation:
1. Seal any unused openings in the venting system.
2. Inspect the venting system for proper size and hor
-
izontal pitch, as required by the National Fuel Gas
Code, ANSI Z223.1 or the Natural Gas and Propane
Installation Code, CAN / CSA B149.1-15 and these
instructions. Determine that there is no blockage or
restriction, leakage, corrosion and other deficiencies
which could cause an unsafe condition.
3. As far as practical, close all building doors and windows
and all doors between the space in which the appli
-
ance(s) connected to the venting system are located
and other spaces of the building.
4. Close fireplace dampers.
5. Turn on clothes dryers and any appliance not connect
-
ed to the venting system. Turn on any exhaust fans,
such as range hoods and bathroom exhausts, so they
shall operate at maximum speed. Do not operate a
summer exhaust fan.
6. Follow the lighting instructions. Place the appliance
being inspected in operation. Adjust thermostat so
appliance shall operate continuously.
7. Test for spillage from draft hood appliances at the draft
hood relief opening after 5 minutes of main burner
operation. Use the flame of a match or candle.
8. If improper venting is observed during any of the
above tests, the venting system must be corrected in
accordance with the National Fuel Gas Code ANSI
Z223.1/NFPA 54 and / or National Gas and Propane
Installation Code CAN / CSA B149.1-15.
9. After it has been determined that each appliance
connected to the venting system properly vents when
tested as outlined above, return doors, windows,
exhaust fans, fireplace dampers and any other gas
burning appliance to their previous conditions of use.
If resizing is required on any portion of the venting system,
use the appropriate table in Appendix G in the latest edi
-
tion of the National Fuel Gas Code ANSI Z223.1 and / or
CAN / CSA B149.1-15 Installation Codes.
