22 v 15 mm !!

[haveago1]

Hi

Am installing a new bathroom and would like opinions on the size of pipe to use. The tap is a 2 valve thermostatic mixer (one valve for bath and one for separate shower). I have taken 22mm hot/cold feeds to the tap.

Question 1 is: on the shower and bath they both have 1/2" bsp connections. Should i therefore just run 15mm from the tap outlets (3/4"bsp) or shall i size down as near to the bath and shower as possible.

2: The shower has a straight connector into the hose outlet which comes out of the wall. Can i just attach a bend with a compression joint and then run the pipe down the wall or would i be best using a wall plate elbow (as below).

http://www.screwfix.com/app/sfd/cat/pro.jsp?cId=100122&ts=64460&id=17416

Thanks in advance!

Forgot to say, system is combi boiler mains fed.

 

[Dan Robinson]

15mm would probably do fine then.

But 22mm for the bath wouldn't hurt any.

 

[haveago1]

so if i were to run 15mm supply to shower and 22mm to bath that would be ok?

Trouble is sourcing a 22mm to 1/2" bsp connector! I have tried but no luck do they do them? otherwise i will have to step down as i mentioned above just before the bath outlet, which presumably would be ok?

cheers.

 

[ChrisR]

Depends on your hot water source. If it's high pressure from a combi you want 15mm pipes to reduce delays and waste.

Gravity supplies are better in 22mm because of the lower resistance.

Where's this 3/4 bsp? A branch from the bath pipes to the basin would be via a 22 to 15mm tee.

How you fix your shower hose depoends on the wall, tiles, outlet fitting etc. There's no single way.

 

[haveago1]

hi thanks for the info

it is a combi boiler so am definitely going to go with a 15mm to shower - still uncertain about bath I take your point about delay but the flow will be so much higher...

The 3/4" is off of the tap which is in the wall. A single tap controls shower and bath, so slightly different to normal...

http://www.bathstore.com/_applicati...alves/shower-bath-valves-concealed/index.html

as per above.

So knowing all this ( ) any other thoughts?

Agree that shower fixing is too hard to sort on the forum and i cant post pics! Cheers!

 

[sooey]

A combi will only give a limited flow of hot water, and 15 mm pipes will be able to carry that, so as has been said any larger will just mean that you have to wait longer for the hot to come through.

 

[kevindgas]

just use a 3/4 Bsp to 15mm adaptor to connect bath taps and definately use 15mm pipe for all your water pipes with a combi

on the continent they use 12mm and guess where combi's came from