User Guide

The position of the damper blade, as supplied, is in the open position. The damper is power-closed/spring-opened, and must be wired

to the zone control panel damper terminals that supply the required 12 VA at 24 VAC. (See zone control panel installation instructions

for specific wiring details.)

CAUTION

1. Sharp edges may cause serious injury from cuts. Use care when cutting openings and handling duct work.

2. A zone control system may not control temperature properly unless the HVAC system is correctly sized and balanced.

3. Install dampers in supply ducts only, and as close to the heating and cooling equipment as possible.

Rectangular Damper Installation Instructions

APRILAIRE RECTANGULAR DAMPER INSTALLATION PROCEDURE

ADJUSTABLE STOP

Each Aprilaire Damper has an adjustable stop screw whose

position determines the amount of rotation the damper blades

make when energized. The stop screw is factory preset to a

position that allows the correct amount of predetermined

bypass air to go through the damper. To adjust the factory

preset bypass setting loosen the stop screw, adjust accordingly

and tighten the screw in place. To completely close the blades,

loosen the stop screw and move it to the closed position.

Step 1: Cut a 4-1/4” slot in the duct wall. Locate slot in side of

duct for side-mounted dampers, and in the bottom of

the duct for bottom-mounted dampers.

Step 2: Gently rotate the damper blade(s), to fit into the cut

slot then slide the damper into the slot until the

faceplate meets the duct wall.

Step 3: Secure faceplate to duct using 1/2 inch long sheet

metal screws (not included).

Step 4: Insulate the same as ducts. Do not insulate actuator.

NOTE: Support all duct work in accordance with local code

or SMACNA standards.

DO NOT

INSULATE

ACTUATOR

0-1419

Preset Adjustable Stop Position

4-1/4”

90-1420

P.O. Box 1467 • Madison, WI 53701-1467 • Phone: 800/334-6011 • Fax: 608/257-4357 • www.aprilairepartners.com

10009392 4.11

B2205467B

Printed in U.S.A.