New bathroom pipe sizes

[colt ceavers]

Hi, im in the process of replacing my bathroom and am a little uncertai

of what size copper pipes to use. My current bathroom was fitted when w had a back boiler but since then i have had a 18Ltr Combi fitted. My question is the existing hot water supply in the bathroom is 22mm t the Hot and 15mm to the cold. Is there any reason to keep the hot a

22mm or would 15 be sufficient. i am also fitting a thermostatic showe would 15mm be enough for that too? my cold supply is high so i am als fitting a pressure reducing valve. Any help and advice would be greatly apreciated. Thanks, colt.

-- colt ceavers

[Nigel Molesworth]

Yes, no.

[John Rumm]

No, Yes ;-)

The combi itself is the limitation on flow rate of hot water, you will note that its mains connection is probably only 15mm, as is the mains to the bath. So 15mm would be fine. Having the 22mm in the feed simply increases the amount of water you waste waiting for the hot to come through. Whether it is worth changing at this stage however is debatable.

[Nigel Molesworth]

Ooops! Missed the combi bit.

[colt ceavers]

thanks for the replys guys, Yes the mains feed is 15mm for the cold but the hot comes in on a 22m and is then reduced to 15mm on feeds to the bath and sink. i think i shall replace it all with 15mm it was just the ne thermostatic shower that i was really concerned about. thanks, colt.

-- colt ceavers