100mm In-line Extractor Fan Vent Back Draught Shutter With One Spring And Two Flaps

Works fine. Ignore the comments about the spring being too weak. It’s not supposed to close on its own. It opens fully when the fan is on and partially closes when the fan turns off. It then closes fully if there is a draught. This is how it’s designed to work. It’s fitted with foam on the back of the flaps to stop them rattling which seems to work fine too.

well it works. kind of. it does help to stop the freezing cold wind blowing through my ceiling vent over my shower cubicle. a lot actually, compared to not having one at all. noise wise, its ok. not silent, when the wind is blowing strongly you can hear it rattling. another buyer gave feedback and recommended putting some thin foam under the flaps... i may try that later. fitting was and still is a nightmare. it is supposed to be compatible or at least work with manrose fittings. that is not true. at all. the device does have a slightly larger opening on one end, above the flaps, which you would assume allows it to push fit onto the electric motor housing (the fan), but it doesn't. its close, but not quite. it needs about another 1mm to fit comfortably. i ended up warming it up with a hair dryer and forcing it onto the housing. a liberal application of "gaffer-tape" and that thing is NEVER coming off. the flexi hose is held on with a zip tie... normally. again, the "gaffer-tape" fixes that issue, lovely.so after a few weeks of use, would i recommend it?strangely, yes.but be prepared to use a bit of ingenuity to get it to fit. Of course, you can just cut the flexihose and and just shimmy it into place with zip-ties. but where's the fun in that?

Having an extraction system in my bathroom I was suffering cold air entering during windy times when the fan was not running. Sadly my fan did not have a non return valve built in so a retrofit unit was the solution. This unit is designed to be a push fit to the inside diameter of 4 inch rigid plastic pipe. In my installation like many others I simply have 4" flexible pipe fitted onto the outlet pipe manifolds of the extractor fan. Therefore this unit is not sized to push inside or outside the fan manifolds as standard so a little adaption is required that may be outside the ability of anyone without suitable tools.I filed a slight bevel to the outside of this unit and then using a Dremmel and sanding tip I sanded a slight bevel inside the fan manifold so the unit just slid inside enough to be secure and taped up with duct tape to be sure. The flexible duct did fit over the unit and was again held secure and sealed with duct tape and all now works well.Some people have made note of the single spring which lightly holds the vanes closed perhaps being too weak. I would point out the design of this shutter is meant to be light so that it does not reduce the fan output force which is usually not that strong especially if it is in longer runs of pipework. If the fan is not running and an incoming draught is present the spring will be strong enough to ensure the vanes move closed.Of additional note, the vanes have small pieces of foam to cushion the closing and because there is no plastic on plastic contact this helps to keep the action quietIt may seem such a simple plastic device is expensive but it solves the backdraught problem and is maintenance free. Although I did not see it specified, I would suggest this unit is best installed in horizontal pipe runs, Vertical sections may have too much gravitational effect to work well without reducing fan output.

Works as should but springs could be ABIT better

Either of flaps are left stuck open even at horizontal position! Look at the pics yourselves.This is pretty useless because it should not allow draught to return when the fan is not operating at all times.

Lightweight twin flap single spring unit. Plastic appears a little flimsy and the spring doesn’t appear to be adequate. However fitted in line between new fan and flexi pipe. Simple use of gaffer tape. Flap appears to work well so all in all a good product.

This is a lightweight plastic valve but it will do the job. It fits nicely onto a spigot on the discharge side of the Manrose ceiling fan I have in the bathroom ceiling. One spring is fitted. This provides just enough force to restore each of the two flaps to the closed position. The spring appears to be mild-steel and will eventually corrode in the humid exhaust air from the bathroom. I fitted the valve with the axis vertically so that the flaps are horizontal. As a result the flaps tend to clatter open/shut when there are strong winds outside. I fitted small strips of self adhesive foam on the seats under the flaps to cushion their landing and also put small pieces of duct tape on the upper side of each flap to provide material damping. The flaps now work well and are silent. Good value for the price if you can be bothered to solve the clattering problem.

Stick this in a few weeks ago . Today we have a gale blowing outside and for the first time the vent is not freezing us . Prior to this the wind blew in through the 4 inch vent pipe on hood extractor and blew full force through the kitchen . Now there isn’t a puff coming through . Very Happy birthday 🎂 with its performance