Where are check valves needed?

[CharlieB1981]

Read other previous posts and the wras regulations and I'm a bit confused as to where in a domestic property I need check valves and if these should be double or single. My shower has built in valves so I don't believe I need others, but is it purely on mixer taps and outdoor taps these are needed, or do I need them on the inflow to the toilet, dishwasher and washing machine also?

Thanks in advance

 

[Newboy]

Double check valves (fitted within the house) on external taps

Mixer taps don't need them provided they have separate internal water channels

ANy mixer with a detachable head does need check valves fitted

WC cisterns (and loft tanks) should have a WRAS approved fill valve or a part 2 valve

Domestic appliances don't need a check valve

 

[CharlieB1981]

Thanks newboy, clear and concise- couldn't ask any more,can I ask are you a plumber yourself?

Also fitting a lone's ale filter which I've just noticed states 'a check valve should be fitted in accordance to wras regulations, does this therefore need a valve before that and the incoming supply?

 

[Newboy]

Not sure what an ale filter is (I tend to think of my kidneys serving that function!)

Belt and braces may need an in-line double check depending on what the risk is

http://www.screwfix.com/c/heating-plumbing/check-valves/cat3830008

 

[CharlieB1981]

That'll be the predictive text, should say limescale filter, heaven forbid fitting an ale filter in the house!