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www.tamcodampers.com

© T.A. Morrison & Co. Inc., 2020

Backdraft

Damper Blade

Linkage

Rod

Zert Nut

Adjustable

Weight

Weight

Locking Nut

Adds more 

resistance

to opening

SERIES 7000 WT  

 

>

Series 7000 WT Weighted Backdraft Dampers have a round, 

adjustable weight and a threaded post secured to the center of 

each blade. A zert nut on the back of the blade is used to lock the 

threaded post in place.

 

>

Each cylindrical, steel weight measures 1¼” 

(32 mm) 

in diameter. 

 

>

Weights are supplied, so that the required resistance to the 

opening of the blade against airflow can be achieved. 

 

>

The cylinder can be adjusted away from or towards the blade, as 

far as the threaded post will allow. 

 

>

Moving the weight away from the blade will increase the amount 

of additional pressure and airflow required to open the backdraft 

damper blades.

 

>

Moving the weight closer to the blade will decrease the amount of 

additional air pressure and airflow required to open the backdraft 

damper blades.

 

>

Additional weights may be added to increase the desired pressure 

build-up before the backdraft damper begins to open.

 

>

Adjust weight placement until desired pressure build-up is 

achieved. 

(Several re-adjustments may be necessary for desired 

operation.) 

 

>

Once adjustment is completed, tighten the weight locking nut to 

prevent weight from moving out of position.

SERIES 7000 CW  

 

>

Series 7000 CW Counterweighted Backdraft Dampers have an 

adjustable ¾” wide 

(19 mm)

 aluminum, counterweight bar attached to 

the back of the blades 

(with the exception of the top blade)

.

 

>

The aluminum bar bracket is centered along the length of the 

blade. This is designed to apply even pressure across each blade. 

Do not move the bar bracket away from the factory-aligned center 

of the blade. 

 

>

Counterweights can be set to relieve air pressure differentials less 

than .01 in. w.g. 

(3 Pa)

.

 

>

To accelerate blade opening, move the aluminum counterweight 

bar further away from the blade. 

 

>

To delay blade opening, move the aluminum counterweight bar 

closer to the blade. 

 

>

To move the aluminum counterweight bar, first loosen the two 

socket head cap screws with a 

3

/

16

” 

(4.8 mm)

 Allen/Hex wrench. 

Do not remove the screws. (

The socket head cap screws secure the 

aluminum counterweight bar in place, through the washer and the 

aluminum bar bracket.)

 

>

Slide the aluminum counterweight bar in the direction required to 

achieve desired blade operation. The counterweight bars should 

be adjusted to the same location on each blade, to ensure that 

even pressure is applied across the entire backdraft damper.

(Several re-adjustments may be necessary. Keep in mind that 

depending on external conditions and damper size, moving the 

aluminum bar to the furthest point away from the blade might 

prevent the backdraft damper from closing.)

 

>

Once adjustment is completed, re-tighten socket head cap screws.

4

TAMCO MEDIUM-DUTY BACKDRAFT DAMPER   |  

Weight Adjustment

For Series 7000 WT & 7000 CW

Backdraft

Damper Blade

Linkage

Rod

Aluminum

Counterweight

Bar
Aluminum

Bar Bracket
Washer

Socket Head

Cap Screw

Acceler

ate

Dela

y

Summary of Contents for 7000 Series

Page 1: ...istance of one 1 fan diameter away from the fan for custom air handler exhaust applications AMCA 200 and AMCA 201 recommend a distance of one 1 duct diameter for each 1000 fpm in order to achieve uniform air at the backdraft damper The type of fan and distance allowed between the fan and the damper will determine the air velocity profile the backdraft damper will be subjected to When backdraft dam...

Page 2: ...and back damper frames securing clips angles to duct work TAMCO recommends that the clips angles should be fastened to the duct work only and not to the backdraft damper This will prevent the fasteners from binding or twisting the damper If access to both sides of the backdraft damper is limited install clips angles to the duct work around the perimeter of either the front or the back frames Then ...

Page 3: ...raight even and aligned with each other 2 Install the bottommost sections of the backdraft damper assembly first 3 T bars are to be installed on the back sticker side of the damper Each T bar will be shorter than the height of a single section This is to ensure that a full T bar piece can be centered across the intersection where four damper sections meet 4 To pierce alignment holes in the damper ...

Page 4: ...ide 19 mm aluminum counterweight bar attached to the back of the blades with the exception of the top blade The aluminum bar bracket is centered along the length of the blade This is designed to apply even pressure across each blade Do not move the bar bracket away from the factory aligned center of the blade Counterweights can be set to relieve air pressure differentials less than 01 in w g 3 Pa ...

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