Overflow Flap?

I have seen (in situ) a flap valve on the end of toilet overflow pipes. Is it possible to buy these things or are they likely to be 'home made'? I have looked in Been & Queued, Homebase, Screwfix and Toolstation with out any luck, Google also doesn't seem to help. Anybody any ideas please?

Cheers

John

Reply to
John
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The usual practice is to fit a tee. This causes the water to drip from the end and not run back down the outside of the pipe to ruin the brickwork. It also reduced draughts.

Reply to
John

Would a right angle not do just as well facing downwards.?

Reply to
NOSPAMnet

What is the purpose of a flap valve?

Rob Graham

Reply to
robgraham

Mainly to stop wind blowing into the pipe and whistling etc. My reason is because of insects! I have a wife that is TERRIFIED of spiders etc. and she saw one crawl in the overflow pipe the other day and asked me how we could stop them. I (foolishly) remarked that I had seen these flaps and now she wants one fitted. I suppose I will have to get my engineering head on and come up with something. I could use a 90 or 45 degree angle with some tights type material sandwiched between the pipe and the angle I suppose.

Cheers

John

Reply to
John

Condom.

Stops the wind blowing up the pipe. Any water trying to get out will fill it up like a baloon until it releases and leaves the pipe to do its stuff.

Reply to
Calvin

if it were me, i'd replace the syphon in the cistern with a torbeck type flush valve with an internal overflow, then remove the old overflow pipe and fill the hole in the wall, and put a blanking plug in the cistern where the old fassioned overflow went.

Reply to
gazz

To stop the wind, put a dip pipe on the inside of the cistern - a 90 degree bend and a bit of pipe, the end of which is about 25mm below the normal full water level.

One of these will all stop insects, although you don't really need the one Alan is holding.

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Bignell

Reply to
nightjar

Not so easy on cistern with a bottom exit overflow...

Dip tubes can also result in a siphon being set up. After changing the overflow arrangements on our main cold water storage tanks I deliberatly held the ball valve open to check the overflow could cope. It did but only just, the level in the tank came above the top of the exit pipe but stabilised once there was a bit of "head". I stopped holding the ball valve open and left it to drain and stop. An hour later the overflow was still running, on investigation the rate of exit via the dip tube and fill from the ball valve balanced each other...

Reply to
Dave Liquorice

That is why the overflow pipe should be one size larger than the inlet pipe.

Colin Bignell

Reply to
nightjar

As has been said on other occasions, it may be easier to change the wife.

Rob

Reply to
robgraham

If the condom has a slit in it it won't fill up and it will stop insects.

Rob

Reply to
robgraham

Define "one size larger". In my siphon case the inlet was mains pressure

15mm at the ball c*ck. The overflow normal Marley 21.5mm stuff.
Reply to
Dave Liquorice

I got a similar effect with the filler and filter on my water butt. Drilling a 1mm hole in the top of the pipework killed the unwanted syphon effect.

Reply to
Andrew Gabriel

And will perish surely?

Reply to
NOSPAMnet

Not sure I want a 1mm hole in the top of the overflow pipe when said pipe by defintion of having a siphon working is full of water and the water level is above the top of the pipes inlet...

The hole can be drilled in the top of the dip tube which is *inside* the tank so water won't go anywhere it shouldn't and the siphon effect will be broken. Now why don't the dip tubes come supplied with a hole?

Very low priority, next time I'm up there and have the insulation and covers off I'll drill the hole.

Reply to
Dave Liquorice

A soft collapseable tube is a good idea but:

a) Condoms are a little larger diameter than 21.5mm overflow pipe. b) Due you want a condom waving in the breeze on the outside of you house? c) How long will it last in daylight? d) Will it reliably open and let water out from a slow overflow after being in place for maybe ten years?

Overall I think the T piece on the pipe end to stop water running back down the pipe on incorrectly installed overflows is the best bet and a IIRC the fly screen is part of the tank connector/dip tube assembly. Doesn't help with bottom exit cistern overflows though.

Reply to
Dave Liquorice

Yes, I drilled mine inside the tank (butt).

I did think it would get blocked, particularly given this is not particularly clean water off a roof and the level in the but does submerge it sometimes, but it never has done. (It's probably a 1.5mm hole -- it was the first bit in the drawer which came to hand which I normally use for drilling holes in PCBs.)

Reply to
Andrew Gabriel

Dunno, maybe you can get some continental ones, they are smaller in diamiter than the english ones.

hehe, i was thinking that too, do you use a T piece on the end of the pipe, hand the jonny from the bottom and put a red light bulb in the top bit of it :)

no idea, they are designed to be used in a dark place after all :D

Maybe you need to ask that Q to mates, tho wording it like that will most likely resuly in a call from the guiness book or records, a couple of minutes is supposed to be average, but 10 years.....

Reply to
gazz

That seems to be an intermediate size, although I would have expected it to work.. The normal overflow for a 15mm inlet would be 22mm copper, or 23mm OD (3/4") plastic.

Colin Bignell

Reply to
nightjar

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