ARAD P20 Meter fitted on 32mm supply???

Hi all, I laid a new water main last year and paid the significant cost to have it hooked up by southern water. Since having it done as I have fitted out the house I notice the flow rates still weren't blowing my socks off when using multiple outlets. I have just gone and had a look at the meter to check it was turned all the way on and noticed it is an ARAD P20 which only has a 20mm bore.

Looking back at the paperwork this is what was specced by southern water but surely it is pointless me laying a new 32mm supply and paying to have it connected if the whole lot flows through a 20mm Meter?? I didn't look up the specs of the meter when signing the paperwork as assumed perhaps stupidly that when asking for a 32mm upgrade they would have specced an appropriate meter? Am I right in thinking this is causing a big bottleneck and making my upgrade from 20mm MDPE to 32mm pointless???

thought it might be worth adding - I have a 32mm stopcock and 28mm copper pipe running to feed various rooms/outlets, all brand new so I do have the infrastructure to take advantage of the high flow rates I should be receiving

If you think of a 30 amp fuse wire being very thin yet still carrying 30Amps its over a very short distance.
Pretty much like your water meter.

jeff the gasman said:

If you think of a 30 amp fuse wire being very thin yet still carrying 30Amps its over a very short distance.
Pretty much like your water meter.

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But to use the fuse analogy, surely this is the equivalent of having a 60 amp cable and running it on a 30amp fuse, the fuse will be the bottleneck in how much you can use. I looked up the specs of the ARAD P20 and its maximum flow rate is 3.125 m3/hour. The ARAD P25 has over double the maximum flow of 7.88M3/hour with a 25mm bore. Seeing as 32mm MDPE has a internal bore of around 26mm, I imagine I would see a drastic increase in flow with an ARAD P25 instead of an ARAD P20??

I have spoken to southern water and despite explaining all of this they couldn't seem to understand so are sending out an inspector to have a look at it for some reason. The maths seems pretty simple to me unless I have got something completely wrong?

BTW - I know I would likely not notice a difference most of the time, but having specced out an overkill main and paid for it, I don't think I am wrong to expect it to perform to the maximum capacity? I plan on having 3-4 bathrooms in the house once done, and we plan on having 4 kids (got 2 girls so far so if I keep shooting girls out I'll need lots of bathrooms!!) so there is definite potential for several showers running at once and I would like to get the best performance I can.

Iknowcraig said:

But to use the fuse analogy, surely this is the equivalent of having a 60 amp cable and running it on a 30amp fuse, the fuse will be the bottleneck in how much you can use. I looked up the specs of the ARAD P20 and its maximum flow rate is 3.125 m3/hour. The ARAD P25 has over double the maximum flow of 7.88M3/hour with a 25mm bore. Seeing as 32mm MDPE has a internal bore of around 26mm, I imagine I would see a drastic increase in flow with an ARAD P25 instead of an ARAD P20??

I have spoken to southern water and despite explaining all of this they couldn't seem to understand so are sending out an inspector to have a look at it for some reason. The maths seems pretty simple to me unless I have got something completely wrong?

BTW - I know I would likely not notice a difference most of the time, but having specced out an overkill main and paid for it, I don't think I am wrong to expect it to perform to the maximum capacity? I plan on having 3-4 bathrooms in the house once done, and we plan on having 4 kids (got 2 girls so far so if I keep shooting girls out I'll need lots of bathrooms!!) so there is definite potential for several showers running at once and I would like to get the best performance I can.

Click to expand...

So 56 lpm will not be adequate?

I am sure it would be more than adequate most of the time. However it is not what I have paid for, I ordered a 32mm supply and have been given a meter which will restrict the flow to less than the supply is capable of.

with regards to the flow, I have a digital shower which when using two outlets can provide 30lpm flow. I will be installing a second soon in the en-suite and potentially a third in another en-suite as I get round to building each one. So with two showers running that's 60 ppm, potentially 90lpm with three running at once. Unlikely to have all 3 running at once but a definitely possibility. Add someone using the kitchen tap/washing machine/dishwasher to that and we could start seeing a drop off in flow which we wouldn't with the 32mm main I specced the house for.

In addition to this usage in the house, I plan on getting a hot tub. Having experienced how slow these are to fill with a garden hose, I have piped 32mm MDPe to the future hot tub location. So I can get the full flow of the main to fill it up. I would definitely notice a difference from the P20 to the P25 in this circumstance as it would double the flow and thus halve the time to fill the hot tub after cleaning.

I am well aware that the 32mm main is complete overkill, but overkill is what I have designed my entire plumbing system around so I want to make the most of it.