RK 5" Professional Backdraft Shutter Damper Connector Duct Fits Only with Metal Ducts

Easy to install - works well to keep the back draft out of our condo's dryer when not in use.

The media could not be loaded.  Shaft sticks out about 1/16 ea side of insert, so I had to trim flush since the fit is skin tight inside standard vent duct on a mobile home rent trailer. I should have weakened the spring before installing since full power fan struggles to open against spring pressure even AFTER ensuring gaps taped with flashing tape. I should have used Hardcast tape ( gooey alum) since I didn't thoroughly clean the area there. The regular stuff isn't stuck well, but I'm thinking the fan motor is due for retirement. It's been getting louder last couple years, and took it out,cleaning w/oil spa didn't do any noticeable good. Sure it works, but it's noisy and underrated and im sure next renter would rather not have a jank hood motor hollarin all thru din. No sense in half measures ol W.W. right about a lot of stuff xsept his biz model one of many others none ive known ended well in that genre. Anyway, hope u learned at least trim the shaft flush to fit inside duct and cavity needs sealed good if the motor has any chance of opening the check against the spring. I'd weaken the spring if I could groundhog day it, but for now ima order another motor since I'm looking for a top shelf tenant in this turd box and that means minimal janky noises or fixes that look daf. It's a nice turd box tho so i put in air fry oven, bidets, bt showerhead. WM fire sale'd at $10/ea so i see it as cheap turd polish loaded the cart Got back and one tenant lit up big smile 😀 bidet!!yay! Totally worth and still 20 of each in my truck. Trailer park Santa feeling warm n fuzzy except wearing old denim bibs and muddy boots. Proper attire all things considered.

Greatly reduced cold air flow into bathrooms through the exhaust fan. Had to install directly onto exhaust fans-not the easiest thing to do. I installed two of the same dampers (both said RK-4 on the box)-the spring tension was quite different. I am hoping damp air does not cause long term corrosion problems.

We live in the mountains and on some days have high winds. The dampers on our ducts on the roof clicked as the wind flowed down the vents. Adding this product to each at the entry of each vent solved the problems.

Insulate the duct above the stove hood to the roof and put the damper just under the roof vent assembly to prevent cold air from flowing in and causing water condensation and seepage. Ignore the so-called experts who tell you different.

It installed perfectly easy, but the damper door doesn't move. It should when the exhaust fan is on. The only reason I gave it 4 stars. Hoping there is a way I can loosing it to make the damper door change position.

While the physical function of the damper works great on the bench, installing it in the intended 4" duct it becomes difficult to keep in position and retain the flap function. You can't install it near the end of a duct because the flaps bind when you connect another piece of duct. If the duct is not perfectly round or does not maintain that perfect roundness the flaps bind and stop operating.Through trial and error I was able to position the damper in the duct about 1/3 the length from the end with the flap axle vertical for minimum load on the springs checking the function. Added a 90 degree elbow to the duct, check again. Added an additional length of duct to the other end, check the function. Install the adapter to the ceiling exhaust fan to the other end of the duct and one last time check the function. Install the assembly in-between the rafters in the ceiling exhausting into the soffit. Wire up and screw the exhaust fan to the rafters connecting it to the duct. Turn the power back on, turn on the fan and minimal air exhausting. Reach up through the 90 degree elbow and into the duct from the soffit and I find the flaps bound up and not opening. So I taped them open so at least the air will exhaust but now you get cold air entering the bathroom when the wind blows.The design flaw is the single rib that holds the unit in alignment and located inside of the duct, that single rib allows the unit to go out of alignment with the slightest amount of torque. I would, and will, purchase a model with 2 or 3 ribs to maintain the alignment and concentricity in the duct.

So I installed a new duct to my garage to help take the edge off the temps in the dead of summer and winter. I didn't want the hot summer air or cold winter air filtering back through the system into my home so I installed one of these to keep the back flow out. Well, as it turns out the air flow through my ducting isn't strong enough to overcome the strength of the spring that keeps the flaps closed. By the time I figured all this out, it was too late to remove it from my installation so I simply put a paperclip on the butterfly flaps to hold it open all the time. So.. it is what it is.

Don't buy this device, it's a nightmare.The baffles drop on the pivot so they are not central to the pipe, then they do not make a seal. A simple washer/collar could have hel them in place.The black plastic baffle seal is too large for the pipe, and has to be remove, then replaced as best possible after insertion of the device into the pipe.Pin and baffle seal aside, the device still does not fit into a 125mm pipe, it is too large. Considerable effort and time was wasted inserting the device without distorting the pin, yes it can be eventually done mm by mm, but is beyond the patience of most.Shoddy construction of the baffle pivot pin, it is poorely riveted and too long, protruding either side of the device.Even with the best effort at modifications, the pin distorts when the device is inserted into the pipe, preventing the baffles from pivoting.

The shutter is made from extremely thin metal. Deforms very easily which is amidst unavoidable when installing onto flexible ducting. Subsequently the shutters to not seat correctly. Even before flexing the shutters do not seal fully allowing draft bypass. The springs are not strong enough either. This is a very poor quality item. Spend a little more to purchase a shutter that stops backdraft. I could not be bothered to return, binned both items and replaced with more expensive but much better quality items.

This is an inline device and will not fit into your existing fan, you will have to cut your vent tube/pipe in half to be able to install. The seal is not rubber, it is a sponge type material, which is not as absorbent as rubber, so you will get a soft clap sound every time there is a pressure differential.I have a humidity sensor in that bathroom and I'm still seeing a small amount of outside humidity, suggesting that the seal when closed is not great.Disappointed to find that it is not a rubber seal - this is false advertising! If I find another solution, I will be returning this unit.

Some have commented that the flaps don't close. I've installed these on three fan / ventilation pipes and they all work fine. I install with the hinge vertically, so the flaps open like doors and close easily. I put them on the exit side of the fan, so the maximum force pushes them open, because in strong winds backdraft can push them shut.

I bought two of these.One to put next to an inline extractor fan in the attic and one for above the kitchen extractor fan as we were getting major draughts through both and they have made a huge difference!Both draughts have now gone and the extractors still appear to work as well as they did previouslyI expected to hear some clattering as we're on the coast and it gets very windy but in the 6 months or more that we've had them I've only heard the one in the attic once or twice and it must have been when the wind was in a very specific direction.Very happy.. Warmer kitchen and bathroom!