Check valves for single lever mixer tap in kitchen?

[Ruv]

I'm a DIYer who'd welcome some advice re. kitchen mixer taps.

I fitted a single lever mixer tap in my kitchen. I'm pretty sure it's not dual flow. Hot comes from the combi and cold I'm pretty sure is mains direct.

Do I need check valves?

cheers

 

[Reg Man]

If the water mixes in the tap body/spout then single check valves are required on each feed, because the cold and hot are different fluid risk categories. If the body/spout are separated to the outlet they do not require check valves. Refer to WRAS Water Regulations Guide section 6 R15.13.2 a and b.

 

[PlumbBobBob]

you can check how flow from the tap mixes quite simply, turn the cold on and see how it comes out of the spout the ndo the same for the hot. if they are the same, the water gets mixed in the tap, if different they don't.

 

[Ruv]

Thanks Reg Man and Steve B

The mixer tap definitely mixes in the tap, cheers Steve.

On the water regs. link you gave me Reg it seems to say that if water pressure is reasonably equal, no need for check valves, and mine seem pretty equal.

Cold from main and hot from combi.

Both have isolation valves and the cold feed may have a ballofix type as I saw an arrow on the side.

Still not sure whether to put checks on both feeds to be on the safe side or it's not needed....

thanks

 

[Reg Man]

Thanks for your comment. You require single check valves on each feed even though they are the same pressure. Section 6 R15.13.2.a second paragraph. Where a combination tap or mixer with water mixing in the body is used with balanced pressures (that is, both inlets are fed from supply pipes or both are from storage) the cold side' is now rated as fluid risk category 1, and the 'hot side' is now rated fluid risk category 2, and single check valves should therefore - according to the Regulations - be installed on both sides.