Ventamatic CX36BD2SPD User Manual

INSTALLATION INSTRUCTIONS

FOR

WHOLE HOUSE FANS

Models:

Read all warnings and instructions before beginning to install this fan.

FAILURE TO FOLLOW THESE INSTRUCTIONS COULD RESULT IN INJURY OR EVEN DEATH

1. Do not attempt to use this fan with any speed control device.

2. Use this unit only in the manner intended by the manufacturer. If you have any
questions, contact the manufacturer.

3. Before servicing or cleaning this unit, switch power off at the service panel and
lock out to prevent power from being switched on accidentally. When service
disconnecting means cannot be locked, securely fasten a prominent warning
tag to the service panel.

4. Installation work and electrical wiring must be performed by a qualified person
in accordance with all applicable codes and standards, including fire-rated
construction.

5. When cutting or drilling into a wall or ceiling, do not damage electrical wiring
and other hidden utilities.

6. The combustion airflow needed for safe operation of fuel-burning equipment
may be affected by this unit’s operation. Follow the heating equipment
manufacturers guideline and safety standards such as those published by the
National Fire and Protection Association (NFPA), and the American Society for
Heating, Refrigeration and Air-conditioning Engineers (ASHRAE), and the local
code authorities.

CX242DDWT, CX302DDWT, CX24BD2SPD, CX30BD2SPD, CX36BD2SPD

CAUTION

1. This unit has an unguarded propeller. Do not use in locations readily

2. For general ventilating use only. Do not use to exhaust hazardous or

3. Carbon monoxide is an odorless, colorless gas that can kill. It may

DOUBLE CHECK FAN BLADES ARE SECURE TO HUB PRIOR TO

INSTALLATION. BLADES CAN BE DAMAGED DURING SHIPMENT AND

CAN BECOME A HAZARD UPON ACTIVATION OF MOTOR!

accessible to people or animals.

explosive materials and vapors.

be drawn into the house by operating this fan if your fuel-burning
equipment is not properly maintained, or if you lack adequate attic

VENTAMATIC, LTD.

100 WASHINGTON STREET, MINERAL WELLS, TX 76068-0728

PHONE: [phone] - FAX: [phone] - www.bvc.com

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INSTALLATION INSTRUCTIONS

VERY IMPORTANT

Please read before attempting installation

The wooden fan frame is installed on top of the joists, and the shutters open up between the joists, so

the rough opening will be smaller than the fan frame size

24-in FANS: DO NOT INSTALL IN AN ATTIC SMALLER THAN 1200 sq ft. This fan requires 8-10 sq ft of
NET FREE EXHAUST AREA, obtainable with (40) 4 x 16, or (15) 8 x 16 soffit or undereave vents, or

equivalent.*

30-in FANS: DO NOT INSTALL IN AN ATTIC SMALLER THAN 1800 sq ft. This fan requires 10-12 sq ft
of NET FREE EXHAUST AREA, obtainable with (66) 4 x 16, or (24) 8 x 16 soffit or undereave vents, or
equivalent.*

36-in FANS: DO NOT INSTALL IN AN ATTIC SMALLER THAN 3000 sq ft. This fan requires at least 14
sq ft of NET FREE EXHAUST AREA, obtainable with (85) 4 x 16, or (31) 8 x 16 soffit or undereave vents,
or equivalent.*

available free air – this can be factored in by measuring the length by the width of the open vent area

DO NOT OVERSIZE YOUR FAN! Additional installation of exterior vents may be required to

provide sufficient Exhaust Area (NFA) for your fan to operate safely and effectively.

Remember – bigger is not better with Whole House Fans. A smaller fan that operates

SHUTTER ROUGH OPENING (L x W)

24-in

30-in

36-in

Veins run lengthwise in 24-in and 30-in shutters, and width-wise in 36-in shutters

Center vein is stationary to allow no-cut joist installation

*For model CX36BD2SPD – The joist-in method may be used only if the joists are 24-in on center, or

greater, and if there is enough space between the involved joist(s) and any walls.

FINISHED OUTSIDE WOODEN FRAME

DIMENSIONS

24-in 28 3/8 x 28 3/8

30-in 35 x 35

36-in 42 1/8 x 42 1/8

*When measuring vents for NFA, remember that louvers and screens cut down considerably on the

and dividing the resulting surface size in half.

efficiently will always be preferable to a fan that is too big for its application.

28 x 26

32 1/4 x 29 1/2

34 x 37 1/2

OUTSIDE SHUTTER DIMENSIONS

24-in 27 3/4 x 28 3/8

30-in 31 1/2 x 33 7/8

36-in 39 1/4 x 35 5/8

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HOW DO THEY WORK?

Whole House Fans are designed to pull in fresh,
cool air from the outside through open windows in
the living space. Hot air is pulled up through the
fan, into the attic, and then exhausted through
static vents in the undereaves, soffits, roof or
gables.

The necessary exhaust ventilation is measured
in square feet of Net Free Area (NFA).
Failure to provide sufficient NFA will reduce the
fan's efficiency, resulting in noisy operation and
the ultimate failure of the motor.

FAN SIZE

24-in

30-in

36-in

SQUARE

FOOTAGE OF

LIVING AREA, OR

ATTIC SIZE IF

MULTI-STORY

up to 1800 sq ft

if 1 story, or attic

size if multistory

2000 to 3000 sq ft

if 1 story, or attic

size if multistory

over 3200 sq ft

if 1 story, or attic

size if multistory

MINIMUM NFA

(NET FREE AREA)

EXHAUST

REQUIRED

8 to 10 sq ft

(1152 to 1440 sq

in)

10 to 12 sq ft

(1440 to 1728 sq

in)

12 to 14 sq ft (1728

to 2016 sq in)

SELECT THE INSTALLATION SITE

Every house is different and there is no set rule for
the choice of the best site. Check the attic
immediately above potential sites for ducts, piping
or wiring that would obstruct the installation area.
The location should also be an area which is open
during operation. Generally they are installed in
hallways or laundry areas. However they should
not be too close to the kitchen or bathrooms so as
not to exhaust unwanted odors, grease, or humidity
into your attic.

The installation site must provide approximately 48-
in of unobstructed clearance between the fan
blades and the roof, in order for the exhausted air
to disperse correctly and not drop back down on the
shutters.

Tools and Materials Needed:

•

Drill

•

1/4” and 1/8” drill bits

•

Straight edge ruler (yardstick, 4 ft level)

•

Pencil or marker

•

Circular saw

•

Ring shank drywall nails (1 1/2”)

•

#12D nails

•

Adjustable wrench

•

Flat head screwdriver

•

Phillips head screwdriver

•

Safety goggles

•

Speed square

•

Saber saw, reciprocating saw

READ THE FOLLOWING BEFORE PROCEEDING

The fan and shutter are designed for horizontal installation only - the louvers will not function in the vertical

position. Decide whether you will use a Joist-In or Joist-Out installation.

Joist-in Installation Joist-out Installation

If you choose this method, you will leave the
ceiling joists intact. You will also need to have
another attic access, as the fan will not fit through
the shutter opening with the joist(s) in place.

This is the preferred method, as the best location
will not necessarily coincide with the position of
the joists. For this method, you will remove one or
more ceiling joists.

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