simple/stupid plumbing question.

skycatcher

Bendy house.... You mentioned using fernox hawk white when doing the job but should i use fernox water hawk as it's on the mains water supply?

Bendy_House

skycatcher said:

Bendy house.... You mentioned using fernox hawk white when doing the job but should i use fernox water hawk as it's on the mains water supply?

Good point, well made. Yup  

In that photo, where is the isolating valve? If that is it on the bottom-right, I'm not sure I follow what's going on. Could you take a wider shot, please, to show it all?

skycatcher

Yes the isolating valve is bottom right in the picture

Bendy_House

If you want the easiest job, just buy the same - chances are it won't leak.

A full-bore valve is always a better choice, but chances are it'll be fractionally longer, so you may need to trim a bit of the pipe end - are you up for this?

If you are, then better still is a full-bore lever valve...

But, any will actually do.

https://www.toolstation.com/isolating-valve-cp/p36879

https://www.toolstation.com/full-bore-isolating-valve-cp/p11495

https://www.toolstation.com/pegler-pb300-lever-ball-valve-blue/p38783

And many in between.

skycatcher

Bendy_House said:

If you want the easiest job, just buy the same - chances are it won't leak.

A full-bore valve is always a better choice, but chances are it'll be fractionally longer, so you may need to trim a bit of the pipe end - are you up for this?

If you are, then better still is a full-bore lever valve...

But, any will actually do.

https://www.toolstation.com/isolating-valve-cp/p36879

https://www.toolstation.com/full-bore-isolating-valve-cp/p11495

https://www.toolstation.com/pegler-pb300-lever-ball-valve-blue/p38783

And many in between.

Yeah I'd really like not to have to cut pipe as it's in an awkward position but would like a full bore valve as i guess this is likely to have least resistance and hence be quietest. I've measured the length of the existing valve and it's 50mm but unfortunately none of the sites mention the dimensions of valves!

Thanks for your help bendy house.

Section62

skycatcher said:

Yes the isolating valve is bottom right in the picture

I'd still say go for a full-bore lever valve, but it looks like there is a 'T' with a pipe going through the wall (outside tap?) - the one immediately above the 'T' for the appliance connection - and this will limit the amount of flex you have in the pipework to make any changes at all.  Is there any scope for movement in the pipe going to the rest of the house as it disappears under the unit?

Also, it might be some kind of optical illusion, but it appears the waste pipe from the sink on the right has a significant uphill gradient.  That's not going to be good in terms of accumulating all kinds of nasties at the lowest point, and potentially water stagnating and smelling after a few days of non-use of the sink.

If you don't feel up to fixing the sink waste, maybe get a good plumber in to do that plus change over the isolating valve?

skycatcher

you are right section 62! the waste from the main sink does go uphill - might explain why its a bit slow to drain....i hadn't noticed being more focussed on the other issues. Yes the external tap is at that t-junction. Thanks for studying the pic so closely and alterting me to the issues.

Bendy_House

Good observes by Section.

The main and centre bowls have been plumbed AoverT - the white U-bend should be on the lowest bowl, which is the main one on the right. This should be quite fixable as the white waste pipe exits out the back of the unit at a low enough level for this - looks like one elbow and a short length of waste pipe should sort it (once flushed with the success of the valve swap, you'll be raring to take this on...)

Ditto with the copper pipe the valve is on - you ideally want some sideways movement in this to make cutting the pipe and slipping on a new valve easy.

SkyC, how much space is there between the pipe and the wall? And, when you grab that valve, is there any movement in it when you gently wobble it side to side, back and forth?

If you want to DIY this and fit the preferred, good-quality ball lever valve, then the worse case scenario is likely to be this (tho' there's nothing to stop you from making the situation worse...):

Use a pipe slice cutter like https://www.amazon.co.uk/Copper-Cutter-Replacement-Cutting-Wheels/dp/B092R22F1M/ref=psdc_1938878031_t2_B001KOTNM6?th=1 These all seem to need around 25mm clearance between the pipe and a wall, and I suspect you don't have this? If you have, say, 20mm space, then very good chance this will still work by slipping it on the pipe sideways, and this will flex the pipe out the required extra 5mm or so. Turn it, and ignore it grating against the wall...Worst case - use a chisel to neatly gouge a groove in the wall first (it's only plaster) of the required depth to allow this to work with the required clearance, probably 10mm or so. This is easy. Just paint it afterwards, after filling or not.

Next issue is if the open pipe ends don't have any sideways movement in them to allow the old valve to come off, or new one on. (You'll need some movement in the pipes in any case, even just to remove the old valve and fit the same back there.) If there really isn't any movement, then you may need to cut the pipe again, say one inch below that soldered tee above.

You'll now have two open pipe ends and a small piece of pipe in your hand...

You sort this by slipping on the new valve to the lower pipe end, and buy a 'slip' 15mm compression coupling to rejoin the other end. A 'slip' coupling doesn't have a ridge inside it, so you can slip the whole coupling right over the pipe, align the pipe ends, and then slip the coupling back down over them both - tighten up. The short piece of pipe will, of course, need trimming to the correct length first - easy.

This is most likely what a plumber would do if you call them out - cut the pipe, remove the old valve, fit the replacement, and then rejoin the (shortened) pipe using a 'slip' solder coupling. It'll be done in a half-hour.

skycatcher

Thanks again bendy.... There seems to be no wiggle room as the pipe is totally rigid with only about 15mm gap behind. Nicer to know the waste system mighty not be too tricky to sort

Section62

Bendy_House said:

The main and centre bowls have been plumbed AoverT - the white U-bend should be on the lowest bowl, which is the main one on the right. This should be quite fixable as the white waste pipe exits out the back of the unit at a low enough level for this - looks like one elbow and a short length of waste pipe should sort it

Difficult to tell from the picture I think, but it is possible the waste has been done that way because the hole through the wall is slightly too high to suit the trap with the W/M connection if it were connected the right way round.  I suspect the person fitting it might have done it this way round to overcome that problem (i.e. to avoid the hassle of making a new hole or buying a more suitable trap).

I'd suggest skycatcher needs to do a bit of measuring up before starting the job - unless it looks a more obvious fit in real life than it does in the photo.

Bendy_House said:

You sort this by slipping on the new valve to the lower pipe end, and buy a 'slip' 15mm compression coupling to rejoin the other end. A 'slip' coupling doesn't have a ridge inside it, so you can slip the whole coupling right over the pipe, align the pipe ends, and then slip the coupling back down over them both - tighten up. The short piece of pipe will, of course, need trimming to the correct length first - easy.

I might be mistaken, but I think this lever valve from Screwfix has an extra deep socket at one end which with care would allow it to be used in the same way as a slip coupler -

https://www.screwfix.com/p/lever-ball-valve-red-blue-15mm/8247v

If anyone has a spare one, or has used one recently, they may be able to confirm if this is the case.  If not, a Screwfix counter would be able to check.

skycatcher said:

Thanks for studying the pic so closely and alterting me to the issues.

Thanks skycatcher.  I should have done better though and noticed that the washing machine(?) drain hose doesn't appear to have a clip on it where it connects to the waste pipe - which means it could come off and flood your kitchen floor.

You'll need one of these to fix that (but check the diameter is right for your hose before buying) -
https://www.toolstation.com/hose-clip/p61289