-- 17 --
When a furnace is installed so that supply ducts carry air
circulated by the furnace to areas outside the space containing the
furnace, the return air shall also be handled by duct(s) sealed to
furnace casing and terminating outside the space containing the
furnace to ensure there will not be a negative pressure condition
within equipment room or space.
UNIT DAMAGE HAZARD
This gas furnace may be used for construction heat
provided that:
--The furnace is permanently installed with all electrical
wiring, piping, air filters, venting and ducting installed
according to these installation instructions. A return air duct
is provided, sealed to the furnace casing, and terminated
outside the space containing the furnace. This prevents a
negative pressure condition as created by the circulating air
blower, causing a flame rollout and/or drawing combustion
products into the structure.
--The furnace is controlled by a thermostat. It may not be
“hot wired” to provide heat continuously to the structure
without thermostatic control.
--Clean outside air is provided for combustion. This is to
minimize the corrosive effects of adhesives, sealers and other
construction materials. It also prevents the entrainment of
drywall dust into combustion air, which can cause fouling
and plugging of furnace components.
--The temperature of the return air to the furnace is
maintained between 55
°
F (13
°
C) and 80
°
F (27
°
C), with no
evening setback or shutdown. The use of the furnace while
the structure is under construction is deemed to be
intermittent operation per our installation instructions.
--The air temperature rise is within the rated rise range on the
furnace rating plate, and the firing rate has been set to the
nameplate value.
--The filters used to clean the circulating air during the
construction process must be either changed or thoroughly
cleaned prior to occupancy.
--The furnace, ductwork and filters are cleaned as necessary
to remove drywall dust and construction debris from all
HVAC system components after construction is completed.
--After construction is complete, verify furnace operating
conditions including ignition, input rate, temperature rise and
venting, according to the manufacturer’s instructions.
CAUTION
!
FIRE, INJURY OR DEATH HAZARD
Failure to follow this warning could result in fire, property
damage, personal injury, or death.
Do
not
install furnace on its back. Safety control operation
will be adversely affected. Never connect return-air ducts to
back of furnace. (See Fig. 15.)
!
WARNING
Step 2 -- Furnace Location Relative to Cooling
Equipment
The cooling coil must be installed parallel with or on downstream
side of furnace to avoid condensation in heat exchanger. When
installed parallel with a furnace, dampers or other means used to
control flow of air shall be adequate to prevent chilled air from
entering furnace. If dampers are manually operated, they must be
equipped with a means to prevent operation of either unit unless
damper is in full-heat or full-cool position.
A07911
Fig. 16 -- Freeze Protection
UNIT DAMAGE HAZARD
Failure to follow this caution may result in minor property or
unit damage.
If this furnace is installed in an unconditioned space where
ambient temperatures may be 32
°
F (0
°
C)or lower, freeze
protection measures must be taken. (See Fig. 16.)
CAUTION
!
Step 3 -- Hazardous Locations
FIRE, EXPLOSION, INJURY OR DEATH HAZARD
Improper location or inadequate protection could result in fire
or explosion.
When the furnace is installed in a residential garage, the
burners and ignition sources must be located at least 18-in.
(457 mm) above the floor. The furnace must be located
or protected to avoid physical damage by vehicles. When
the furnace is installed in a public garage, airplane hangar, or
other building having a hazardous atmosphere, the furnace
must be installed in accordance with the NFGC or
NSCNGPIC. (See Fig. 17.)
!
WARNING
Step 4 -- Furnace Location and Application
DIRECT VENT (2-PIPE) APPLICATION
Furnace may be located in a confined space without special
provisions for dilution or ventilation air.
18-IN. (457.2 mm)
MINIMUM TO BURNERS
A93044
Fig. 17 -- Installation in a Garage
58MCB