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Plumbing advice

Weekend_Woodworker

Weekend_Woodworker

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I wondered if I can call on the collective wisdom of forum members to help solve a plumbing issue I am not sure how best to fix. The extractor fan for our main bathroom vents through our roof via some pipes in our loft. The geometry of the arrangements means that there is in effect a U-bend in the pipe. Whilst I have done my best to lag the pipe (some of which has been removed in the photo below) some of the steam still condenses in the pipe. Over time this water accumulates so that the pipe can become blocked and I have to go into the loft with a bucket to drain the water out. It is fairly infrequent e.g. once a year but I would like to avoid it. I can't easily get enough space to get the pipe out at the eaves so it only goes down hill, therefore I was wondering about trying to connect a small diameter pipe from the elbow going down to the eaves, however I am not sure how to make a good watertight connection to the plastic elbow. Does anyone have any advice or experience of how I might solve this please?

loft pipe picture.jpg

Many thanks,

Mark
 
Change the left most 90 degree bend for a swept tee and use inter size adaptors (possibly need several) to get down to 22.5 overflow pipe. Run that to the eaves and outside. It will only produce the odd drips of water that can just fall to the ground.
A screwfix/ toolstation catalogue has loads of pictures of the various plumbing parts you could use

HTH
Bob
 
Why not simply run the existing size pipe horizontally to vent down through the soffit or facia board. Ie as 9fingers suggests but without reducing the pipe size.
 
We had a similar problem but ours was condensation forming on the outside of the duct. Lots of secondary insulation solved that.

If you don't want to permanent drain or feed it to the soffit, you can get insulated ducting, you can get flexible as well, so you could get rid of some of those bends.
 
Hang on, I'm not getting it.
This is an extractor fan, yes? for air, not water.
Why does it need to be watertight?
Why is that shape?

assuming we are talking air flow, then cut the left hand pipe as high to the ceiling as you can, put a 90 degree elbow on, and connect the two ends with 2" flexible hose.
 
Its an air vent, and its getting condensation, what is there not to get?
Its getting condensation because of the length of it, and its collecting because of the u bend.
Remove the u bend, reduce the pipe to the absolute minimum length, and what condensation does occur it will be so slight as to not be noticed.
Connecting the fan to the light switch so it runs all the time the light is on will also reduce problems.

Or, take the pipe horizontally though the roof with a slight drop to the outside and the problem will never recur.
 
My twopennerth having installed a quite a number of vented extractors through roof space though I've been retired a few years so fans may have changed in spec.

First: That is a poor design, there should not be a U bend in a vent pipe, it should have a smooth a passage as possible or it's not doing the job properly and overworking the extractor.

Second: That looks to me like standard 40mm waste pipe which in my experience is not large enough capacity, normally 100/110mm would be used or proprietary plastic expanding tube of similar dia

So you have several options.
Replace the pipe with the correct size and run it at an angle to rafter height using swept bends extract through the roof, you can reduce there to existing 40mm but only if you must, I wouldn't.

Similar using the expanding tube which is as cheap as chips, mine own are run at joist level as the stuff is easy to locate and insulate. Not as good as pipe as it's ridged but works fine.

Retain the existing pipe but re route similar to the first option above, I still think it's too small!

Live with what you have but replace the last bend with a tee and reduce one outlet to a drain off pipe routed to the outside or put a stopcock on the end so you can easily drain when you need to.
 
Thanks for all the replies. Bob (9 fingers) I like the idea you propose and will look into that. I understand SunnyBobs idea of just taking it all straight down to the eaves, but there isn’t enough space without changing the pipe diameter, and then I still have a pipe through the roof.

Best wishes,

Mark
 
Hi Lons, Sorry I missed your reply when responding last night. The pipe is actually 110mm diameter. I accept that the design is poor, and I will try and reduce the angle at the bend. Unfortunately the extraction for the bathroom is very close to the ridge, I can't get a 110mm pipe down to the eaves, I have an existing 110mm pipe through the roof and I don't like heights or have the access to change things outside on the roof. That all said the idea of taking a smaller pipe off the bend. I see in screwfix that they do a 110mm access bend which might be possible to fit another pipe to. They don't seem to do a T joint though.
 
This may sound too simpple but cant you just put a vent tile at ceiling hieght and connect the 4" grey pipe to that? eliminate the drop and u bend all together. IE run it horizontally where it comes through the bathroom wall and out to the fresh air?
 
Hi Mark
My mistake it looks like 40mm but I shouldn't have assumed that. :oops:

Bob's suggestion of a boss is the easiest and cheapest solution if you can't re route it.
 
Morning Mark

https://www.toolstation.com/extractor-f ... low/p73185

Fitted above the fan. Continuous rise on the exhaust pipe to the outside air terminal.

Any condensation ( or rain entering the roof terminal) falls back to the trap and drains via the small radial outlet to a pipe with a continuous fall to the outside world.

Any good?

Cheers

Dave
 
Hi DeeJay,

I like that and wasn't aware such things exist. My slight snag is that I am working with 110mm pipe not 100mm. I could change the pipe from the extractor, but I couldn't readily change the bit going through the roof. :eusa-think:
 
could that condensation trap have an outside diameter of 110mm?? would pop to ts and ask to see one. if it is 110 then a couple of straight couplings and job done
 
Weekend_Woodworker":3qvw9i7c said:
Hi DeeJay,

I like that and wasn't aware such things exist. My slight snag is that I am working with 110mm pipe not 100mm. I could change the pipe from the extractor, but I couldn't readily change the bit going through the roof. :eusa-think:
Click to expand...
Hello Mark

Something like this might do, fitted on the vertical 110 pipe below the roof outlet ...

https://www.i-sells.co.uk/circular-adap ... m-to-100mm

Cheers

Dave
 
Thanks for all the ideas and suggestions. I liked the idea of the condensation collector, but then thought I might need two, one for each pipe that came down. The boss was a good idea, which would avoid the need to change the pipes, but I wasn’t sure how close I could connect it to the bend where I really wanted it. I have therefore decided to try these parts:
BBAC528A-2095-4BBB-BA0D-539974F24602.jpeg

Hopefully I can then fix this into the flat surface from the access panel which will allow me to run a pipe direct from the bend:

DCB972EA-83C9-468C-BDFA-604A1F43BC6B.jpeg

I had hoped to get the bits this weekend but I obviously spent too long pondering it and won’t have the bits till Monday. Hopefully I will be able to post a photo of it when it is all done if anyone is interested

Once again many thanks for all the help and ideas that have got me to this solution.
 
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