FANTECH9800004 RSK-6 Backdraft Damper, 6" Duct

This damper can be used in a downdraft mode, but only with modification because the flaps otherwise remain open even when there is no airflow. I modified it by connecting each flap to an end of a fine chain about 4" long (from Ace). To attach the chain to the flaps, I inserted cotter pins through the ends of the chain, and then inserted the cotter pins through holes I drilled in the flaps about 3/8" in from the edges (along a line perpendicular to the flap-hinge in the plane formed when the flaps are closed). Before attaching the chain the the flaps, you might want to put a small-key-ring on the chain so that the ring slides along the chain. Trim off any excess from the cotter pins if necessary so they don't prevent the flaps from opening or closing.To pull the flaps closed, the center of the chain is pulled up with a tensioner-line (details below). I attached a 90 degree elbow to the top of the damper and ran the tensioner-line straight up through a small hole which I drilled in the elbow, to a small spring hanging from a screw-eye. To allow the flaps to open, the wire is unhooked from the spring and allowed to go slack, although it's still connected to the screw eye to prevent it from falling and becoming inaccessible.The tensioner-line consists of the aforementioned small key-ring, and stranded insulated wire, which offers flexibility while minimizing the likelihood of breakage due to rubbing on the edges of the hole through the duct.There might be better approaches for the tensioner-line. For example, baling wire could be run through the chain's center link, then through a small washer, and then bent to prevent the washer from falling off. (The washer would presumably allow the wire to rotate without catching on the chain.) This approach would allow the tensioner-line to twist without ever twisting the chain, and it would prevent the tensioner-line from becoming worn due to rubbing on the edge of the hole through the duct. The baling wire would extend only to the outside of the aforementioned duct-elbow, and there be connected to a something more flexible. I didn't try this approach, because the combination of the ring and the stranded insulated wire works well enough (so far), and I didn't want to start over to experiment with another approach.I tried using baling wire before I adopted the ring, but I had simply bent the wire around the chain loosely, and when the tensioner-line was allowed to go slack, the wire would catch on the chain and push down on it, thus holding one of the flaps closed. But if the wire were simply run through a link, it probably could not push down on the chain, but I'd have to try it to be sure because Murphy's Law has not been repealed.To hold the damper down to the floor, I used fender washers and lag screws to press down on the bulge/flange near the damper's output. It's probably not the ideal approach, but it works, and I had the parts handy.

Yes, obviously I can see how this damper is constructed in the pictures before I bought it. I read one of the reviews talking about a solution since it won't do a downdraft, without the flaps simply staying open due to gravity. Since I'm doing a horizontal vent I didn't pay much attention to it.But this is something I feel is an important consideration for other potential buyers of this damper; WILL YOU BE ABLE TO GET TO THIS AFTER IT'S INSTALLED? I'm finishing a ceiling. This is for a bathroom exhaust. It will be in the ceiling near the wall where it meets an elbow and vent.The spring for the two flaps? It is almost as thin as a hair! You can easily blow the flaps open with even a normal breath. Others mentioned this as praise for the flaps opening easily... but here's where my design question comes in for the manufacturer. You could have easily opening, and positive closing... while losing that spring and the split-hinged flaps.If the flaps fall open under gravity anyway, then why not keep it one piece, with two vertical wires ("bars", like the current one down the center that the split-flaps are hinged on)... so the single piece flapper is perfectly centered in the vent... then simply have two holes at the top that the two wires are bent through (just like the current design)... and then the whole flapper would open with even less resistance, and close by gravity. (optionally, you could angle this within the damper, so that even if the damper is at a slightly downward angle the flap would still close very securely)... you'd save production costs with a simpler design... plus eliminate that hair-fine spring and the hinged split-flapper.You could accomplish this angled, securely self-closing flap within the current cylinder with the foam rubber seal at an angle.Sure, the outer cylinder is totally bomb-proof... so yes, thank you for that... but the mechanism... the reason we're buying this... is all built on extremely delicate parts. Why? I can't help wondering how many years this will last and/or if the hinged assembly will need any cleaning or maintenance when I can no longer get to it?That's why 3-stars... "it's okay"... yes, the outer cylinder is ridiculously well-constructed and solid... but on inspection, I'm surprised just how delicate the important bits are... the hinged flaps, and especially the tiny spring.

I bought this and a mega-quiet Broan XB50 fan for my bathroom. The old fan was a little piece of junk and was insanely noisy, and since it was wired to come on with the bathroom light, it wasn't possible to take a quiet, relaxing, contemplative dump. This was really harshing my mellow. Also, there was no backdraft damper so the bathroom would be 15-20 degrees colder than the other rooms in the house. Not a fun bathroom to use.Install was easy. There is a cotter pins that protrude from either side and holds the piano hinge in place, but I just taped right over them: they can remain fixed in position and the flaps still work as intended. I don't know why so many people were griping about this, it was not a big deal.As for the backdraft prevention, the dampers seal against a foam ring. A very slight amount of cool air still comes through, but it's 95% mitigated and I'm satisfied with this.As for the noise - the little semicircular flaps produce a fluttering noise, which is a real bummer because I spent top dollar on a quiet fan. But it's a lot more quiet than the old fan, and keeping the cold air out is more important than total silence. If I were to do it over again, I would try to find a backdraft damper that didn't produce as much noise - there is a sleeve damper I've seen that looks interesting.

I had this fixed in my kitchen chimney duct. Helps to prevent back draft, very strong wind outside, sea facing. Exact fit for 4" aluminium duct

Worked as expected, though you couldn't mount it any other way than vertically inline with your duct. I was disappointed with the seal of the flaps to the rubber gasket as there were noticeable gaps (as large as 1/8", a little better fit and finish attention would make this a 5 out of 5.

In the description it indicates "spring loaded for positive closure" When I received this product I was disappointed to find that it is not spring loaded for positive closure. It will not work in a horizontal position-it does not close by itself with the assistance of springs. It is more a gravity closure and will only work in a vertical configuration. The documents enclosed in the package indicates that it is most suited for a vertical installation-THAT IS CORRECT....But it does not indicate that in the Product description when I ordered it. I would like to return this for a full refund.

Good quality Backdraft damper.

Just a ducky damper...