15mm v 22mm

[lc04]

Excuse my ignorance here but why is 22mm so important where hot water is concerned, is it all to do with heat expansion of the water?

For example I have a combi at present in a 2 bed g/f flat and I will be removing my bath soon and installing a shower only. In my 'airing cupboard' where the tank used to go there is some 22mm pipe which will feed the bath taps at present and to 'T' off this for a run of about a metre I will be installing my mixer for the new shower (currently electric with cold feed only of course).

Is it ok to 'T' off with just 15mm to supply the hot feed or is it best to stick to 22mm for as long as possible.

 

[wiggikins]

15mm will be fine, if in doubt consult installation details !

 

[lc04]

15mm will be fine, if in doubt consult installation details !

Thanks, but what is the deal with 22mm anyway?

 

[seco services]

combi is mains pressure
i take it before you had gravity system so 22mm was used bigger pipe better flow.
try and fill a bath with 15mm pipe under gravity.

 

[lc04]

combi is mains pressure
i take it before you had gravity system so 22mm was used bigger pipe better flow.
try and fill a bath with 15mm pipe under gravity.

Point taken and yes of course you are right.