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Discuss Why hot water copper pipe is 22mm and cold is 15mm? in the Bathrooms, Showers and Wetrooms area at PlumbersForums.net

JohnMalcolm

Messages
6
Hi All,
I have this silly question. Water pressure for hot water is a bit low while cold water has a decent pressure.
Why do they put 22mm copper pipes for hot water? It seems detrimental for already low pressure.
Best regards
 

Last Plumber

Esteemed
Plumber
Gas Engineer
Messages
4,480
Why do you think it detrimental?
The larger pipe bore reduces pressure loss. If the hot is open vented/tank fed and has low pressure, that is the reason 22mm has been used.
 

SimonG

Esteemed
Plumber
Messages
20,582
As above, you will find a lot of hot water feeds to baths in 22mm all due to old tank fed hot water. Just like a lot of cold feeds to baths are in 15 as its mains.
 

adomas

Messages
7
There is a cold water tank in the loft. And a hot water tank in the airing cupboard. The current pipe work is about 20 years old. The hot 15mm pipe that's currently there feed straight down stairss to a utility sink. The cold 15mm is the direct feed in from the main stop tap.
 

Reply to Why hot water copper pipe is 22mm and cold is 15mm? in the Bathrooms, Showers and Wetrooms area at PlumbersForums.net

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