Mix of 15mm & 22m pipes & low pressure

22 Dec 2012
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United Kingdom
Hi there,

Any advice on low(ish) hot water pressure in upstairs bathroom in house weve bought would be most appreciated.

1930s detached medium sized house.

Set up is after stopcock in hall the cold feed goes straight upstairs to bathroom and toilet, before travelling to back of house and down in to kitchen and boiler (Worcester Greenstar 24i, 1 year old). All pipes after stopcock to boiler are 15mm.

Hot water then leaves boiler in 15mm splitting for kitchen /downstairs toilet and going upstairs for 4 metres before it Changes to 22mm under the back bedroom (where old immersion was???) then a further 5metres in 22mm to the bathroom taps where it comes out sluggish.

Hot water in downstairs toilet seems good (better than upstairs) and think hot water in kitchen was ok (that's from memory as kitchen Taps are currently sealed off as kitchen being gutted).

So is the last leg of the upstairs feed being 22mm causing low flow????? Or is there some other issue (boiler too small??)????

Any advice would be really appreciated, thanks

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Sounds to me like the hot water out should have started as 22mm then after splitting reduced to 15mm that would probably have been a better way of doing it but there may be another reason like using standard isolating valves on taps instead of full flow ones. Or small bore flexible pipes,
Thanks for taking the trouble to reply.

Nothing on the house has been standard, owned by a lovely old lady for years and she was either taken advantage of or had a son in law who didn't frequent this forum!!!

Think original house set up hasn't helped either.

Any chance you could elaborate (I'll have a google as well) on your other points you mention (valves and pipes)??


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