SYSTEM OPERATION
10
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.
PROVIDE 8" MINIMUM CLEARANCE BETWEEN
CENTER ROD AND FURNACE CABINET TO
ALOW FOR CIRCULATOR BLOWER REMOVAL.
ALTERNATE
GAS PIPING
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.
CONDENSATE
DRAIN
TILT OUTWARD TO ALLOW FOR
DOOR AND CIRCULATOR
BLOWER REMOVAL
POSITION AS CLOSE AS
POSSIBLE TO BLOWER DECK TO
ALLOW FOR CIRCULATOR
BLOWER REMOVAL.
2"x2"x1/8" ANGLE IRON
(3 PLACES)
GAS PIPING
SUPPORT
NUTS
HOLD DOWN
NUTS
3/8" DIAMETER
THREADED ROD
(6 PLACES)
Suspended Furnace
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, latest
edition, 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 continuously;
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 terminal
is recommended.
Thermostat Location
In an area having good air circulation, locate the thermostat
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
following:
•
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
dehumidistat, such as an outside wall.
Consult the instructions packaged with the thermostat and
dehumidistat for mounting instructions and further precautions.
COMBUSTION AND VENTILATION AIR
REQUIREMENTS
WARNING
P
O
SS
IBLE
P
R
OPE
R
TY
DAMAGE,
PE
RS
ONAL
IN
J
U
R
Y
O
R
DEATH
MAY
OCCU
R
IF
THE
FU
R
NACE
I
S
NOT
P
R
OVIDED
WITH
ENOUGH
F
R
E
S
H
AI
R
FO
R
P
R
OPE
R
COMBU
S
TION
AND
VENTILATION
OF
FLUE
GA
S
E
S
.
MO
S
T
HOME
S R
E
Q
UI
R
E
OUT
S
IDE
AI
R
BE
S
UPPLIED
TO
THE
FU
R
NACE
A
R
EA.
Improved construction and additional insulation in buildings
have reduced heat loss by reducing air infiltration and escape
around doors and windows. These changes have helped in
reducing heating/cooling costs but have created a problem
supplying combustion and ventilation air for gas fired and
other fuel burning appliances. Appliances that pull air out
of the house (clothes dryers, exhaust fans, fireplaces, etc.)
increase the problem by starving appliances for air.
