507651-01
Issue 1907
Page 5 of 32
General
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
In addition to the requirements outlined previously, the
following general recommendations must be considered
when installing one of these furnaces:
•
Place the furnace as close to the center of the air
distribution system as possible. The furnace should
also be located close to the chimney or vent termination
point.
•
Do not install the furnace where drafts might blow
directly into it. This could cause improper combustion
and unsafe operation.
•
Do not block the furnace combustion air openings with
clothing, boxes, doors, etc. Air is needed for proper
combustion and safe unit operation.
•
When the furnace is installed in an attic or other
insulated space, keep insulation away from the
furnace.
•
Please consult the manufacturer of your evaporator
coil for their recommendations on distance required
between the heat exchanger and their drain pan.
Adequate space must be provided between the drain
pan and the furnace heat exchanger.
Combustion, Dilution & Ventilation Air
In the past, there was no problem in bringing in sufficient
outdoor air for combustion. Infiltration provided all the air
that was needed. In today’s homes, tight construction
practices make it necessary to bring in air from outside
for combustion. Take into account that exhaust fans,
appliance vents, chimneys, and fireplaces force additional
air that could be used for combustion out of the house.
Unless outside air is brought into the house for combustion,
negative pressure (outside pressure is greater than inside
pressure) will build to the point that a downdraft can occur
in the furnace vent pipe or chimney. As a result, combustion
gases enter the living space creating a potentially
dangerous situation.
In the absence of local codes concerning air for combustion
and ventilation, use the guidelines and procedures in this
section to install these furnaces to ensure efficient and
safe operation. You must consider combustion air needs
and requirements for exhaust vents and gas piping.
A portion of this information has been reprinted
with permission from the National Fuel Gas Code
(ANSI-Z223.1). This reprinted material is not the complete
and official position of the ANSI on the referenced subject,
which is represented only by the standard in its entirety.
Insufficient combustion air can cause headaches,
nausea, dizziness or asphyxiation. It will also cause
excess water in the heat exchanger resulting in rusting
and premature heat exchanger failure. Excessive
exposure to contaminated combustion air will result
in safety and performance related problems. Avoid
exposure to the following substances in the combustion
air supply:
•
Permanent wave solutions
•
Chlorinated waxes and cleaners
•
Chlorine base swimming pool chemicals
•
Water softening chemicals
•
De-icing salts or chemicals
•
Carbon tetrachloride
•
Halogen type refrigerants
•
Cleaning solvents (such as perchloroethylene)
•
Printing inks, paint removers, varnishes, etc.
•
Hydrochloric acid
•
Anti-static fabric softeners for clothes dryers
•
Masonry acid washing materials
WARNING
NOTWITHSTANDING THE FOREGOING, INSTALLER
IS RESPONSIBLE FOR CONFIRMING THAT THE USE
OF CONSTRUCTION HEAT IS CONSISTENT WITH
THE POLICIES AND CODES OF ALL REGULATING
ENTITIES. ALL SUCH POLICIES AND CODES MUST BE
ADHERED TO.
