Mains cold to bathrooms in 22 or 15?

[Scottley]

Hi all

Im carcassing out my new loft conversion. I have a 250lt megaflo to go in but im stuck on the pipe size for the cold main. I have run the hot feed to the bathrooms in 22 and reduced down to 15 for the basins but wondered whether it was necessary to run this in 22 or 15? Also should i run it straight from the main or from the balanced supply? The shower feeds will be balanced and in 22.

Thanks

 

[tackleburger]

I would put a 3 bar PRV on the mains into the house. If possible tee cylinder off in 22mm first from the main or as close as possible and don't tee anything of the cylinder feed. From the cylinder use 22mm to the bathroom and tee appliances off maintaining 22mm as close to bath as you can get.

Good practise to tee shower off cylinder direct you can use 15mm.

As for cold supply you can go from anywhere really (exept cylinder feed) if you have a PRV on the incoming main.

 

[Scottley]

I would put a 3 bar PRV on the mains into the house. If possible tee cylinder off in 22mm first from the main or as close as possible and don't tee anything of the cylinder feed. From the cylinder use 22mm to the bathroom and tee appliances off maintaining 22mm as close to bath as you can get.

Good practise to tee shower off cylinder direct you can use 15mm.

As for cold supply you can go from anywhere really (exept cylinder feed) if you have a PRV on the incoming main.

Thanks, i have the PRV that comes with it but planned to put that in the cupboard with the megaflo and take all services after it and the feed to the megaflo. As for the hot i have a 22 under the floor for the fees tot he bathrooms but showers will come off a tee and go up through ceiling to the showers.

I want it to all be as efficient as possible as i hate waste.

Im planning on putting a CWS tank in the loft for rain water harvesting to run the toilets, for some reason the kids think its fun to flush it for no reason!