PRODUCT DESIGN
20
A furnace installed in a confined space (i.e., a closet or
utility room) must have two ventilation openings with a total
minimum free area of 0.25 square inches per 1,000 BTU/
hr of furnace input rating. 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 adequate to satisfy this ventilation
requirement.
Furnace Suspension
If suspending the furnace from rafters or joist, use 3/8"
threaded rod and 2”x2”x1/8” angle iron as shown in the
following figure. If the furnace is installed in a crawl space
it must also be suspended from the floor joist or supported
by a concrete pad. Never install the furnace on the ground
or allow it to be exposed to water. The length of rod will
depend on the application and the clearances necessary.
TILT OUTWARD TO ALLOW FOR
DOOR AND CIRCULATOR BLOWER
REMOVAL.
3/8" DIAMETER
THREADED ROD
(6 PLACES)
PROVIDE 8" MINIMUM CLEARANCE BETWEEN
CENTER ROD AND FURNACE CABINET
TO ALLOW FOR CIRCULATOR BLOWER REMOVAL.
ASSURE FURNACE IS LEVEL FROM
END TO END.
ON
90% FURNACES
MAKE SURE
THE UNIT HAS A SLIGHT
FORWARD TILT WITH THE FRONT
OF THE FURNACE 0"-3/4"
BELOW THE BACK OF THE FURNACE.
POSITION AS CLOSE AS POSSIBLE
TO BLOWER DECK TO ALLOW FOR
CIRCULATOR BLOWER REMOVAL.
2"
X
2"
X
1/8"
ANGLE IRON
(3 PLACES)
HOLD DOWN
NUTS
SUPPORT
NUTS
CONDENSATE
DRAIN
GAS PIPING
ALTERNATE
GAS PIPING
Suspended Furnace
E
XISTING
F
URNACE
R
EMOVAL
NOTE:
When an existing furnace is removed from a vent-
ing system serving other appliances,
the venting system
may be too large to properly vent the remaining attached
appliances.
The following vent testing procedure is reproduced from the
American National Standard/National Standard of Canada
for Gas-Fired Central Furnaces ANSI Z21.47, latest edi-
tion, CSA-2.3b, 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:
a. Seal any unused openings in the venting system;
b. Inspect the venting system for proper size and horizontal pitch, as
required by the National Fuel Gas Code, ANSI Z223.1 or the CSA
B149 Installation Codes and these instructions. Determine that
there is no blockage or restriction, leakage, corrosion and other
deficiencies which could cause an unsafe condition;
c. In so far as practical, close all building doors and windows and all
doors between the space in which the appliance(s) connected to the
venting system are located and other spaces of the building. Turn
on clothes dryers and any appliance not connected 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. Close fireplace dampers;
d. Follow the lighting instructions. Place the appliance being inspected
in operation. Adjust thermostat so appliance shall operate continu-
ously;
e. Test for draft hood equipped spillage at the draft hood relief opening
after 5 minutes of main burner operation. Use the flame of a match
or candle;
f.
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;
g. If improper venting is observed during any of the above tests, the
common venting system must be corrected.
Corrections must be in accordance with the latest edition of
the National Fuel Gas Code NFPA 54/ANSI Z223.1 and/or
CSA B149 Installation Codes.
If resizing is required on any portion of the venting system,
use the appropriate table in Appendix G in the latest edition
of the National Fuel Gas Code ANSI Z223.1 and/or
CSA B149
Installation Codes.
Thermostat Requirements
A high quality single stage thermostat with a common termi-
nal is recommended.
Thermostat Location
In an area having good air circulation, locate the thermo-
stat and dehumidistat (if applicable) about five feet high on
a vibration-free inside wall. Do not install the thermostat or
dehumidistat where it may be influenced by any of the fol-
lowing:
•
Drafts, or dead spots behind doors, in corners, or
under cabinets.
•
Hot or cold air from registers.
•
Radiant heat from the sun.
•
Light fixtures or other appliances.
•
Radiant heat from a fireplace.
•
Concealed hot or cold water pipes, or chimneys.
•
Unconditioned areas behind the thermostat and de-
humidistat, such as an outside wall.
Consult the instructions packaged with the thermostat and
dehumidistat for mounting instructions and further precau-
tions.
COMBUSTION AND VENTILATION AIR
REQUIREMENTS
WARNING
P
OSSIBLE PROPERTY DAMAGE, PERSONAL INJURY OR DEATH MAY OCCUR
IF THE FURNACE IS NOT PROVIDED WITH ENOUGH FRESH AIR FOR PROPER
COMBUSTION AND VENTILATION OF FLUE GASES. MOST HOMES REQUIRE
OUTSIDE AIR BE SUPPLIED TO THE FURNACE AREA.
