Form 43343050
-32-
Jan 2014
B.
B.
B.
B.
INDIRECT VENTING (UNVENTED HEATERS)
INDIRECT VENTING (UNVENTED HEATERS)
INDIRECT VENTING (UNVENTED HEATERS)
INDIRECT VENTING (UNVENTED HEATERS) — This heater requires ventilation in the building to dilute the
products of combustion and provide fresh air for efficient combustion. Where unvented heaters are used,
gravity or mechanical means shall be provided to supply and exhaust at least 4 CFM per 1,000 Btu/hr input
of installed heaters. Exhaust vents must be located at the highest point above and in the vicinity of the
heaters, and the inlet vents must be located below the level of the heaters. An exhaust hood (Accessory Part
No. 42924000) must be placed directly on the 4”starting collar of the draft inducer (refer to section 10)
when the heater is used UNVENTED
UNVENTED
UNVENTED
UNVENTED.
Exhaust Hood
(no starting collar necessary)
-Required for UNVENTED use-
END VIEW
17.0)
AIR FOR COMBUSTION
If indoor combustion air is to be supplied for a tightly enclosed area, one square inch of free area opening shall
be provided below the heater for each 1,000 Btu/hr of heater input. Adequate clearances around the air inlet
screen must be maintained at all times. In larger open areas of buildings, infiltration normally is adequate to
provide air for combustion.
17.1)
AIR FOR COMBUSTION – HORIZONTAL THROUGH A SIDEWALL
Outside combustion air should be supplied directly to
the heater when the building is subject to negative
pressure, or when contaminants or high humidity are
present in the building air. These contaminants include
paints, solvents, corrosive vapors or any other foreign
particles that may cause damage to the heater or
result in poor combustion.
Outside combustion air can be brought directly to the
heater by a 4" diameter duct (field supplied) less than
20 ft. long or equivalent. An approved vent cap and 4”
Control Box
Perforated
Air Inlet Plate
CAUTION
If installation of this heater is
made in a non-poultry
application and without the use
of fresh air ducting, a perforated
air intake plate PN 42752000
must be installed over the
cabinet hole opening.
Failure to due so may result in
damage to the control.
flexible hose (supplied in accessory Kit #44129510) must be connected to the duct as shown below. Connect
the 4” flexible hose directly to the 4” starting collar (supplied with heater). This is used to allow for
expansion/contraction of straight configuration tube heaters.
The combustion air inlet should be not less than 3 ft. (0.9m), either vertically or horizontally, from the flue vent
termination. The air intake terminal must be located not less than 1 ft. (30cm) above grade. It is good
installation practice to supply combustion air from the same pressure zone as the vent outlet. Avoid bringing
combustion air to the heater from an attic space. There is no guarantee that adequate combustion air will be
supplied.
Flexible Air Intake Hose: Insure that the Air Intake Hose connection is not too tight between the control box and
Flexible Air Intake Hose: Insure that the Air Intake Hose connection is not too tight between the control box and
Flexible Air Intake Hose: Insure that the Air Intake Hose connection is not too tight between the control box and
Flexible Air Intake Hose: Insure that the Air Intake Hose connection is not too tight between the control box and
the Air Intake. The air intake hose can become disconnected as the heater expands
the Air Intake. The air intake hose can become disconnected as the heater expands
the Air Intake. The air intake hose can become disconnected as the heater expands
the Air Intake. The air intake hose can become disconnected as the heater expands and contracts during
and contracts during
and contracts during
and contracts during
operation.
operation.
operation.
operation.
Note: A cold air stopper is not used with fresh air intake through a sidewall.
Note: A cold air stopper is not used with fresh air intake through a sidewall.
Note: A cold air stopper is not used with fresh air intake through a sidewall.
Note: A cold air stopper is not used with fresh air intake through a sidewall.
