non return valves

[malp]

Hi I am fitting a new bath, basin and toilet and am installing isolation valves to all hot and cold water supplies.

Do i also need to fit non return valves and what is the differance between single check and double check valves.

Any advice would be appreciated and if I do need these non return valves are they all the same or can u recommend which type I should use.

Many thanks

 

[gigz]

If the taps are mixers and you have different pressures (i.e. cold from mains, hot from cylinder) it is advisable to fit check valves on the hot near the tap, this is to stop the cold pushing the hot back up. If separate taps no need. Single check has one valve double check has two. We use crosco, never had any bother with them.

 

[malp]

Thanks for your reply. So what exactely is the differance between single check and double, and where should you use each.

Also is it part of water regs that you have to fit these and do you only fit them on the hot supply.