I'm installing a heatbank / heat exchanger to get mains pressure on all taps and showers in the house. But as far as I can see the mains pipe coming in under the kitchen sink is just 15 mm. I need 22 mm. What do I do - and what'll it cost ?
Cheers larry
First actually test the flow rate. Under some conditions, 15mm can actually give an adequete flow rate. If not, then the replacement will not be cheap. Think in terms approaching four figures, especially if the route goes under block paved driveways etc. You may be forced to have a water meter. However, unless you use hosepipes and sprinklers, meters are likely to save you money.
Also, you might want to check that the mains in your area are good enough. In some cases, ancient Victorian mains are well undersized as requirements and housing density has increased, and will have poor flow/pressure characteristics themselves.
Christian.
It is normal for the water supply to be 15mm your side of the c*ck and 22 mm on the water company side,so if that is the case it should not be to difficult to change the supply to 22mm.
The recent splitting from the neighbours supply which was shared from a single approx 15mm / half inch steel pipe off the 3" main in the road, and we had to go on a meter the board plumbed it all the way in 25mm Blue plastic pipe, which I continued in same size into the house and then on in 22mm copper. the Bath taps jointly give a flow rate of
44 litres a minute and the shower around 15 to 20 litres a minute depending on summer or winter. Fan-blinking-tastic shower I can assure you !Nick
If you do some of the work yourself then there is no reason it should cost so much. Prices only really start to rise if you have to dig up a concrete kitchen floor, for example.
I bought a roll of 25mm MDPE blue pipe from my local merchants, dug up the front garden and drilled a big hole through the front of the house to get the pipe through to the sub-floor space. Be sure to sleeve the 25 mm in
28mm or 32mm plastic waste where it passes through the brick.Then I called the water company to come and connect it which they did for free considering I was replacing lead. They also connected me into my own
68mm main in the street so now the pressure could blow you out of the bath. Actually, I have to reduce the pressure but it will be useful if I ever need to do some crowd control. hehe!From the 25mm MDPE go to 22mm copper.
HTH Rob
As it happens I need to do this myself soon; and have been scratching my head over the specs diagram I've just received from the water co. It shows the MDPE pipe coming through the wall, minimum 750mm below ground, sheathed in another pipe as you describe. However, it stipulates that the min radius of the sheathed pipe is 750 mm! ie, as drawn, it must come up through the kitchen floor at least 750mm from the outside wall! This bears no resemblance to any installation I've ever seen, and makes no sense to me at all. Can anyone shed some light on this???
David
The 750mm is only enforceable if you don't insulate the pipe. Put some insulation around it and you are allowed to go up to the surface provided you guard it against breakage.
The pipe is not that bendy but will go much tighter than a 750mm radius. Try a piece, it's quite obvious where the kink point starts. The water contractors won't be that bothered so it really is up to you how you route the pipe within your property. Make sure it is all loose when they turn up so they can feed it into the outside stopcock easily.
You could fit a 90 bend after it enters the wall or start the bend further out so that it enters the wall already at an incline. The sheathing pipe can be anything handy, an offcut of basin waste or cable duct and is only needed for the bit actually in the wall.
My contractors thought my (exactly to spec) deep trench quite funny as the main was only 400mm deep in the street.
750mm! Forget it. There is not one of my properties that complies with that.
Like all things DIY, when working on ones own property, you will be far more cautious/careful than any 'approved' installer. When I suggested the sheathing to the guys that turned up to do the connection they just laughed at me. Seriously!
Everyone I have spoken with has said that MDPE is stronger than it looks and not to be too concerned with scratching it or compressing it etc. Of course, wanting to do the job properly, I ignored them all and took care of what I did, running it under the (to be installed) concrete floor within an electrician's 50mm conduit which was available with a nice radius bend that brought it vertical to my kitchen wall without having to sink 750mm down. I also used this to run a few cables along, which was helpful.
Frankly, ignore the 750mm spec and do what you feel is correct. The guys who come to acutally connect the thing in the road will know a fraction of what you do.
HTH Rob
You may like to go under the floor amd check if someone put a MDPE to 15mm convertr in, that you can swap to a 22mm.
Rick
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.