Valve mixer shower - 22mm vs 15mm supply

[AndersonC]

The thermostatic valve mixer shower I have got to fit has 22mm inputs, hoever the supply running from the boiler and cold mains is in 15mm. How much of the shower supply should be plumbed in 22mm? Just the 'tails' to connect to the shower, or do I need to start thinking about replacing lots of 15mm with 22mm?


Thanks for advice

 

[powell30]

I would just plumb the last section onto the tails as 15-22mm.....most combi's supply out in 15mm

 

[cider]

make sure the valve is suitable for high pressure. if it has 22mm connections it may be gravity feed. also if your installing for a customer what flow rates are the expecting

 

[AndersonC]

Thanks for the responses, the shower is for me, so I want a nice fast flow, the brochure does say that it is suitable for high pressure.

 

[cider]

Thanks for the responses, the shower is for me, so I want a nice fast flow, the brochure does say that it is suitable for high pressure.

if your boiler is a combi and only has 15mm outlets then there is no point in increasing pipe size. Most combis give a respectable shower.

 

[ChrisR]

If it's a combi I would be more inclined to do the reverse - remove 22 and replace with 15! The resistance is negligible for several metres, and you'll wait longer for your hot water.