Positioning The Furnace; Combustion Air And Ventilation; Duct Recommendations - Dettson LOW-BOY AME15-79 Guide D'installation Et Manuel Du Propriétaire

2.2

POSITIONING THE FURNACE

The unit must be installed in a location where the ambient
and return air temperatures are above 15° C (60° F).
WARNING
This furnace is not watertight and is not designed for
outdoor installation. It shall be installed in such a
manner as to protect the electrical components from
water. Outdoor installation will lead to a hazardous
electrical condition and to premature furnace failure.
This furnace is approved for reduced clearances to
combustible construction.
basement or on the same level as the area to be heated. In
any case, the unit should always be installed level.
If the unit is installed In a basement, or on a floor (as in a
crawlspace), it is recommended that it be installed on a
concrete pad that is 25 to 50 mm (1 to 2") thick.
The minimum required clearances for this furnace are
specified in Table 4.
The furnace should be located as closely as possible to the
chimney or vent in order to keep vent connections short and
direct. The furnace should also be as close as possible to
the center of the air distribution system.
2.2.1

Combustion air and ventilation

Refer to the CAN/CSA-B139 installation code for complete
regulations and for guidance on retrofit applications.
This furnace should be installed in a location where air
supply permits proper combustion of the oil, proper venting
and the maintenance of an ambient temperature at safe
limits under normal conditions of use. The location should
not interfere with proper circulation of air within the confined
space.
In addition to the air needed for combustion, process air
shall be provided as required for cooling of equipment or
material, controlling the dew point, heating, drying, oxidation
or dilution, safety exhaust, odour control, for ventilation,
including all air required for comfort and proper working
conditions for the occupants.
WARNING
Do not block the combustion air openings in the
furnace. Any blockage
combustion and may result in a fire hazard and/or cause
bodily harm.
The barometric draft regulator shall be installed in the same
room or enclosure as the furnace in such a manner as to
prevent any difference in pressure between the regulator
and the combustion air supply.
Air requirements for the operation of exhaust fans, kitchen
ventilation systems, clothes dryers, and fireplaces shall be
considered in determining the adequacy of a space to meet
such combustion air requirements.
This unit may be located in a
will result in improper
In unconfined spaces, in buildings of conventional frame,
brick or stone construction, infiltration may be adequate to
provide air for combustion, ventilation and dilution of flue
gases. This determination must be made on an individual
installation basis and must take into consideration the overall
volume of the unconfined space, the number of windows and
ventilation openings, the number of doors to the outside,
internal doors which can close off the unconfined space and
the overall tightness of the building construction.
Many new buildings and homes and older ones that have
been weatherized, must be considered as being of tight
construction and, therefore, infiltration will not be sufficient to
supply the necessary air for combustion and ventilation.
A building can be considered as being of tight construction
when:
a.
Walls and ceilings exposed to the outside atmosphere
have a continuous water vapor retarder, with a rating of
one perm or less, with sealed openings and/or
b.
Weather-stripping
windows and doors, and/or
c.
Caulking or sealant are applied to areas such as joints
around windows and door frames, between sole plates
and floors, between wall-ceiling joints, between wall
panels, at penetration points for plumbing, electrical and
fuel lines and at other openings.
2.2.2

Duct recommendations

The proper sizing of warm air ducts is necessary to insure
satisfactory furnace operation.
accordance with the latest editions of NFPA-90A (Installation
of Air Conditioning and Ventilating Systems) and NFPA-90B
(Warm Air Heating and Air Conditioning Systems) or
Canadian equivalent.
The supply ductwork should be attached to the flanged front
opening provided at the discharge end of the furnace and
return air ductwork should be attached to the flanged rear
opening of the furnace. See Figure 2 for the dimensions of
this opening.
The following recommendations should be followed when
installing ductwork:
a. Install locking type dampers in all branches of the
individual ducts to balance out the system. Dampers
should be adjusted to impose the proper static pressure
at the outlet of the furnace.
b. A flexible duct connector of noncombustible material
should be installed on the unit on both the supply and
return air system. In applications where extremely quiet
operation is necessary, the first 3 meters (10') of supply
and return ducts should be internally lined with
acoustical material.
c. In cases where the return air grille is located close to the
fan inlet, there should be at least one 90° air tur n
between fan inlet and grille. Further reduction in sound
level can be accomplished by installing acoustical air
turning vanes or lining the duct as described in
paragraph b. above.
d. When a single air grille is used, the duct between grille
and furnace must be the same size as the return
opening in the furnace.
4
has been added on
Ductwork should be in
operable