Question about mains water pressure/connection

[Stu666]

Looking for some advice please:

Around 7 years ago we had a leaking old lead water supply pipe replaced. Due to the layout of the house and to avoid digging up what was then a brand new tarmac driveway, the water supply was relocated to the other side of the house, where there was an existing outside tap fed by 15mm copper pipe. Water pressure here seems quite good, indeed a rudimentary test with a bucket and stopwatch reveals a flow rate of about 18 - 20 litres/minute. However, beyond this point, things start going a bit downhill. The copper pipe from outside tap travels up into loft space above our kitchen, where it branches off into the rest of the house. Flow rate at the kitchen tap is about 8.5 litres/min, yet paradoxically the bath tap upstairs is about 11 L/M. Does this seem right? We have a thermostatic shower running off a new boiler with 30KW hot water output, but flow rate has never been amazing.

Secondly, I was checking for leaks recently and opened up the chocbox for the first time. I was quite surprised to find the water supply is coming up through soil in 15mm speedfit pipe before connecting to 15mm copper pipe. I definitely remember the contractor laying blue MDPE pipe, so I suspect they have teed the MDPE pipe with a three way connector, the third outlet serving the outside tap. I am planning to dig down to check for sure. But something is telling me regular white speedfit pipe buried in soil (and possibly a speedfit type connector) probably isn't right?

 

[Madrab]

chocbox

Only ever heartd that for electrics??

No - the water mains should not be coming up out of the ground in 15mm speedfit. If you are getting 18-20L/Min at the outside tap then it shouldn't really be losing half that by the time it gets to the bath unless the dynamic pressure is poor? Do you know what that is?

That being said too - if it's all 15mm then if the dynamic pressure isn't the best then yes, that could impact the flow by the time the water has run all the way around the house.

 

[Wayners]

 

[Stu666]

Only ever heartd that for electrics??

Apologies, I think the proper term is an INSUduct box. But I could've sworn overhearing someone calling it a chocbox as it looks like a giant piece of chocolate

 

[Stu666]

This is what I found after taking the box off. Planning to take a flag up this weekend and see what's going on below.

 

[Madrab]

Ah yep, an Insuduct, not hear it called a chocbox before, though I do see why.

Oh my, nope that isn't right at all if that's your mains supply. I hope that 15mm plastic just runs to the outside tap and the mains is fed in somewhere else. Where is your mains stop tap?

 

[Stu666]

Ah yep, an Insuduct, not hear it called a chocbox before, though I do see why.

Oh my, nope that isn't right at all if that's your mains supply. I hope that 15mm plastic just runs to the outside tap and the mains is fed in somewhere else. Where is your mains stop tap?

The mains stop tap is on the other side of that wall in the kitchen loft space (single story extension). It was originally the stop tap to the outside tap. It's difficult to see from the photo, but that is the only entry point in the wall. There is nothing below it, and from memory they didn't drill any new holes at the time, literally connected up to what was already there. They wouldn't have been able to get to the other side anyway, due to fitted kitchen cabinets. There was definitely blue MDPE pipe as I remember helping them dig the trench and saw them lay it. But I didn't pay attention when they were connecting it all up. Definitely suspect they have teed MDPE to speedfit underground, but will need to excavate to check for sure.

Question is, what are the ramifications of this work, and how to best put it right? I'm pretty handy with Speedfit myself having plumbed a few new radiators in with it, but no experience with water mains. I know how to shut the supply off at the street though through bitter experience

 

[denso13]

Question is, what are the ramifications of this work, and how to best put it right?

Open it up first, to see what you are dealing with.

 

[Hugh Jaleak]

I think you'll need to excavate around the base of the Insuduct, and see if you can find the end of the Blue MDPE, if you got that, (then ensure the supply does shut off at the street end!), and remove what you have, and replace with MDPE into the Building at least.

Insuduct offer a 'Hockey Stick', pre made 'L' shape pipe to fit into the duct and get you through the wall, once inside reconnect to the internal Pipework, and I'd run a new feed back out for the Outside Tap.