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Clearances and combustion air, Suspending the heater – Reznor BE Unit Installation Manual User Manual

Page 7

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Form RZ-NA-I-FE/BE, Mfg P/N 98807, Rev 10, Page 6

Figure 3 -
Confined Space: A
space whose volume is
less than 50 cubic feet
per 1000 BTUH of the
installed appliance
input rating

Figure 4 -

Suspension

NOTE: If the installation includes an optional stepdown transformer
kit (Option CF or CG), the stepdown transformer bracket is part of the
heater suspension and must be installed prior to hanging the heater.
Follow the instructions on the installation sheet included with the op-
tion kit.

A fan-type unit heater is equipped with standard two-point suspen-
sion. A 3/8-16 threaded hanger bracket assembly is located on each side
of the heater. If a fan-type unit has been ordered with optional, factory-
installed, four-point suspension (Option BJ6), it will have two threaded
hanger brackets on each side.

A blower-type heater is equipped with standard four-point suspen-
sion. Two 3/8-16 threaded hanger bracket assemblies are located on
each side of the unit. Each hanger bracket assembly is designed for
threaded rod attachment.

For both "standard" and "optional" suspension point dimensions, see
Dimension Tables in Paragraph 3. (Note: If installing Option CK19
hanger kit, suspension points change; see Figure 7.)

WARNING: Suspend the heater only from the
threaded hanger brackets. Do not suspend from
the heater side panel.

When the heater is lifted for suspension, the bottom must be protected.
If the wooden crate bottom has been removed, the bottom of the heater
will have to be supported with plywood or other appropriately placed
material. If the bottom is not supported, the bottom access panel could
be damaged. Also, when lifting a blower unit, support the blower and
motor to prevent the unit from tipping.

* When supplied with optional downturn nozzle, bottom clearance is

42"(1067mm). For service purposes, on standard units, bottom
clearance exceeding minimum (12" or 305mm) is not required but
may be desirable.

** For servicing purposes only, rear must remain full open.

All fuel-burning equipment must be supplied with the air that enters
into the combustion process and is then vented to the outdoors. Suffi-
cient air must enter the equipment location to replace that exhausted
through the heater vent system. In the past, the infiltration of outside
air assumed in heat loss calculations (one air change per hour) was
assumed to be sufficient. However, current construction methods uti-
lizing more insulation, vapor barriers, tighter fitting and gasketed doors
and windows or weather-stripping, and mechanical exhaust fans may
now require the introduction of outside air through wall openings or
ducts.

The requirements for combustion and ventilation air depend upon
whether the unit is located in a confined or unconfined space. An "un-
confined space" is defined as a space whose volume is not less than 50
cubic feet per 1000 BTUH of the installed appliance. Under all condi-
tions
, enough air must be provided to ensure there will not be a negative
pressure condition within the equipment room or space. For specific
requirements for confined space installation, see Paragraph 8.

WARNING: These power-vented unit heaters are
designed to take combustion air from the space in
which the unit is installed and are not designed for
connection to outside combustion air intake ducts.
Connecting outside air ducts voids the warranty
and could cause hazardous operation. See Hazard
Levels, Page 2.

8. Combustion Air Requirements

for a Heater Located in a
Confined Space

Do not install a unit in a confined space without providing wall open-
ings leading to and from the space. Provide openings near the floor and
ceiling for ventilation and air for combustion as shown in Figure 3,
depending on the combustion air source as noted in Items 1, 2, and 3
below the illustration.

7. Clearances and Combustion

Air

Units must be installed so that the following clearances are provided for
combustion air space, service and inspection, and for proper spacing
from combustible construction. Clearance to combustibles is defined as
the minimum distance from the heater to a surface or object that is
necessary to ensure that a surface temperature of 90°F above the sur-
rounding ambient temperature is not exceeded.

Model

Required Clearances (inches and mm)

S i z e

Top

Flue

Sides

Bottom

Rear

Collector

25-400 6"(152)

6"(152)

18"(457)

12"(305) *

24" (610)**

Add total BTUH of all appliances in the confined space and divide by
figures below for square inch free area size of each (top and bottom)
opening.
1. Air from inside the building -- openings 1 square inch free area per
1000 BTUH. Never less than 100 square inches free area for each
opening. See (1) in Figure 3.

2. Air from outside through duct -- openings 1 square inch free area
per 2000 BTUH. See (2) in Figure 3.

3. Air direct from outside -- openings 1 square inch free area per 4000
BTUH. See (3) in Figure 3.

NOTE: For further details on supplying combustion air to a confined
space, see the National Fuel Gas Code ANSI Z223.1a (latest edition ).

9. Suspending the Heater

Before suspending the heater, check the supporting structure to be
used to verify that it has sufficient load-carrying capacity to support
the weight of the unit.

Net Weight (lbs and kg)

Model

S i z e

Type

25

50

75

100 125

165 200 250 300 400

Fan

lbs

7 6

8 3

9 2

1 0 1 1 3 2

1 5 4 1 7 5 2 0 9 2 2 6 2 8 1

kg

3 4

3 8

4 2

4 6

6 0

7 0

7 9

9 5

1 0 3 1 2 7

Blower

lbs

9 7 1 0 4 1 1 8 1 3 0 1 8 0

2 0 6 2 4 0 2 7 8 3 0 1 3 9 5

kg

4 4

4 7

5 4

5 9

8 2

9 3

1 0 9 1 2 6 1 3 7 1 7 9

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