lead pipe replacement

showerfreak · Posted: Fri Feb 09, 2007 10:46 pm Post Subject: lead pipe replacement

I am replacing the lead supply but the builders have installed 20mm pipe instead of the 25mm recommended by the water authority. The switch over has not yet been done and we have had installled a new combi boiler worcster bosch 40 cdi running on the exisitng lead supply. The mains pressure on the lead is not bad but with the combi it is lower. MY REAL CONCERN: as the builers have laid 20mm instead of 25mm will I loose pressure on my shower ( which hasnt yet been instaled.) Its bad becaue they have already buried the 20 metre pipe.

BoxBasher · Posted: Fri Feb 09, 2007 11:31 pm Post Subject:

Has it been inspected yet? Most inspectors, especially Severn Trent (which I believe you probably are being Staffs, unless you are Very north Staffs) will insist on 25mm minimum, although it depends on what the Water Co have specified... as you say 25mm has been mentioned.

ChrisR · Posted: Sat Feb 10, 2007 2:33 am Post Subject:

What's the length of the 20mm?

showerfreak · Posted: Sun Feb 11, 2007 10:11 am Post Subject: lead replacment

OK guys, the severn trent inspector is a bit of a anorak and hasnt insited with the builders that it has to be all 25mm. He is letting the builders get away with it and has asked for the end that they connect to be 25mm in so therefore a joint needs to be made from 20mm to 25mm.

The lenght is aprox 20 metres.

I dont really want to have to get the builders to dig up again unless its really required.

Im hoping the 20mm plastic has a larger diameter to the lead pipe and hence better flow and I understand that it wont affect the shower ( which is my main concern ). The plumber , who is the builders brother, says i will get better flow than the lead anyway.

I have been reading about flwo and pressure and have got to understand the difference.

So what do you guys think any issues or should i kick up a stink.

doitall · Posted: Sun Feb 11, 2007 10:20 am Post Subject:

You kick up a stink and tell the builder you asked for and are paying for 25mm and not 20mm, you also expect him to replace it at his cost.

Best done in writing for future reference.

And yes it will make a lot of difference to the flow rate.

showerfreak · Posted: Sun Feb 11, 2007 11:33 am Post Subject:

OK next question is can anyone inform me what the diameter of the exsting lead pipe might be.

doitall · Posted: Sun Feb 11, 2007 11:46 am Post Subject:

showerfreak wrote:

OK next question is can anyone inform me what the diameter of the exsting lead pipe might be.

No it depends on the weight.

could be anything from 3/8" to 2" is the biggest I've used, but no doubt you could get bigger if you really wanted too.

BoxBasher · Posted: Sun Feb 11, 2007 1:30 pm Post Subject: Re: lead replacment

showerfreak wrote:

He is letting the builders get away with it and has asked for the end that they connect to be 25mm in so therefore a joint needs to be made from 20mm to 25mm.

Thats just because water co don't carry 20mmPE fittings...

showerfreak · Posted: Sun Feb 11, 2007 6:03 pm Post Subject:

SO I understand I will loose some flow but the pressure will remain the same. Does anyone have any commnets as to whether or not the 20mm pipe will loose performance over 25mm when using the shower. Im installing a Mira excel

doitall · Posted: Sun Feb 11, 2007 6:22 pm Post Subject:

Without getting the books out you will lose approximately 60% of the volume with the smaller pipe :O

That doesn't mean 20mm will not do the job but it could do, especially if the pressure is low.

stumpynut · Posted: Sun Feb 11, 2007 6:31 pm Post Subject:

What type of system will be supplying the hot water ?

showerfreak · Posted: Tue Feb 13, 2007 8:26 pm Post Subject:

Its a newly installed combi worcester bosch greenstar 40cdi and its meant to have 16 litre permi flow.