User Guide

INDICATOR
LABEL
BRACKET
MOTOR
ADJUSTABLE
STOP SCREW
90-1652
Preset Adjustable Stop Position
(shown with plastic cover removed)
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 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.
4. Do not force damper blades closed by hand, as damage may occur.
Zone Control System
Round Damper Installation Instructions
ROUND DAMPER
SUPPLY DUCT
AIR FLOW
DIRECTION
APRILAIRE ROUND 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. The Preset Adjustable
Stop Position illustration above shows the correct position. If
the stop screw is not set at the position indicated, loosen it,
slide it directly under the dark band on the indicator label, and
tighten the screw in place. To completely close the blades,
loosen the stop screw and move it in the direction indicated by
the black arrow on the indicator label.
Step 1: Install damper with crimped end downstream.
Step 2: Slide damper over end of crimped duct and secure
to duct with 1/2 inch long sheet metal screws
(not included).
Step 3: Insulate damper the same as ducts. Do not insulate
the actuator.
NOTE: Support all duct work in accordance with local code
or SMACNA standards.
DO NOT
INSULATE
ACTUATOR