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C
OMBUSTION
& V
ENTILATION
C
ATEGORY
I V
ENTING
A
IR
R
EQUIREMENTS
EXISTING F URNACE R EMOVAL
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 reproduced from the
American National Standard/National Standard of Canada
for Gas-Fired Central Furnaces ANSI Z21.47-Latest Edi-
tion, 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:
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 CAN/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 appliance 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 CAN/
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 CAN/CSA B149
Installation Codes.
THERMOSTAT L OCATION
In an area having good air circulation, locate the thermostat
about five feet high on a vibration-free inside wall. Do not install
the thermostat where it may be influenced by any of the follow-
ing:
• 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, such as
an outside wall.
HOT
COLD
Thermostat Influences
Consult the instructions packaged with the thermostat for mount-
ing instructions and further precautions.
C
OMBUSTION
AND
V
ENTILATION
A
IR
R
EQUIREMENTS
T
O
AVOID
PROPERTY
DAMAGE
,
PERSONAL
INJURY
OR
DEATH
,
SUFFICIENT
FRESH
AIR
FOR
PROPER
COMBUSTION
AND
VENTILATION
OF
FLUE
GASES
MUST
BE
SUPPLIED
.M
OST
HOMES
REQUIRE
OUTSIDE
AIR
BE
SUPPLIED
INTO
THE
FURNACE
AREA
.
WARNING
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 burn-
ing appliances. Appliances that pull air out of the house (clothes
dryers, exhaust fans, fireplaces, etc.) increase the problem by
starving appliances for air.
House depressurization can cause back drafting or improper
combustion of gas-fired appliances, thereby exposing building
occupants to gas combustion products that could include car-
bon monoxide.
If this furnace is to be installed in the same space with other
gas appliances, such as a water heater, ensure there is an
adequate supply of combustion and ventilation air for the other
appliances. Refer to the latest edition of the National Fuel Gas