2

Most of the duct dampers don't provide 100% seal from air flow. The below picture might be. I have collar with damper, But its just not enough to stop/bypass the air flow.

what is this called in the picture highlighted, Fiber stripping, what kind of it is ?

It seems the strip is glued to the metal. enter image description here

thanks!

1

1 Answer 1

2

It may be a simple weatherstripping that was added.

It is rare to completely block a trunk line. In fact I have seen trunk lines split open because they were blocked off. The home owner did not understand what he was doing when trying to convert a multi level home from 60-40 to 40-60 and split a large duct in the wall.

In another case the blocked both main trunks with the fan on and it split the duct from the Y to the furnace.

The few times I have done this is for garages or basements not normally conditioned so a more positive or complete seal is made.

To do this I have used weather stripping. I have used silicone, but have found metal riveted in place with a compliant rubber stays in place and seals better.

The quality of the seal and how well it is installed can seal close to 99% and self adhesive sponge rubber seals can do as good but don’t last long and can blow out with higher duct pressures.

7
  • Thanks. So what you are suggesting is use any weather stripping and the seal it with a silicone ? I'll have to make sure the stripping works in extreme weather and is also fire retardant. can please you recommend a link?
    – PowerTech
    Jun 3, 2021 at 19:07
  • Will this work? it seems open cell homedepot.com/p/…
    – PowerTech
    Jun 3, 2021 at 19:34
  • Vicky that foam will work it works well for a couple of years then needs to be replaced but it is inexpensive and works.
    – Ed Beal
    Jun 3, 2021 at 20:03
  • 1
    I used door seal like a metal strip that has a rubber strip that is soft and round the door closes on it usually nailed in, I used a touch of silicone and pop rivets that seal is a life time verses the foam that works but breaks down.
    – Ed Beal
    Jun 4, 2021 at 1:02
  • 1
    Neoprene would work but is usually fairly stiff. Putting 1/2 on one side from the pivot and 1/2 on the other side from the pivot will work as it allows the plate to move away from the seal points. Make sure to allow any sealant / glue to dry prior to trying to close the damper under pressure. Although you may only have a couple of inches water Column pressure a 8” duct has a lot of force and will move the seal (a mistake from years past), I rivet because I can’t wait 3-4 hours for the sealant to cure.
    – Ed Beal
    Jun 8, 2021 at 22:37

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.