15mm or 22mm pipes?

[badger4279]

Hi, I have replaced my old cylinder with a worcester greenstar 30cdi combi boiler. The old cylinder fed the bath taps using a 22mm pipe that was then reduced to feed all the other taps in the house to 15mm.
Should I still use a 22mm pipe on my new bath taps or will 15mm pipes be ok.

 

[kevplumb]

22 won't hurt

15 should be ok

 

[jctilingservices]

Hi, I have replaced my old cylinder with a worcester greenstar 30cdi combi boiler. The old cylinder fed the bath taps using a 22mm pipe that was then reduced to feed all the other taps in the house to 15mm.
Should I still use a 22mm pipe on my new bath taps or will 15mm pipes be ok.

according to Worcester, the pipework to the bath taps should be 22mm, use 15mm and thats when you start to get problems, and it voids the gaurantee, wrongful fitting

 

[badger4279]

Thanks. I've checked the fitting instructions that came with my Worchester boiler. It states the Domestic Water Outlet feed from the boiler should be 15mm. I've checked the manifold and it is designed only to accept 15mm pipes. Im a bit confused how I can therefore use 22mm pipes to feed the bath taps. Shall I just use a 15 to 22mm expansion joint. If so how far from the boiler would you recommend I do this. Thanks again!.

 

[seco services]

15mm fine on a combi boiler.
22mm you'll waste more water waiting for the hot to come through.

 

[bengasman]

according to Worcester, the pipework to the bath taps should be 22mm, use 15mm and thats when you start to get problems, and it voids the gaurantee, wrongful fitting

Not in my manual, it doesn't; 15 mm for dhw on a 30CDI.
If 22 is already in place, I would not replace it if it was in good knick, but it doubles the response time.