Use check valves with monobloc tap?

[Rich82]

Hi

I'm wanting to replace my mixer tap in the kitchen with a monobloc mixer.
Will I need to use check valves with the tap tails that came with the tap?
Also what are they? (plumbing novice)

Cheers in advance

 

[cantaloup63]

Yes. The cold water supply to the kitchen is always (or should be) mains supply, whereas the hot water may or may not be. The check valves are to prevent contamination of the cold water mains supply on the one hand, whilst preventing backflow from the cold to the hot on the other.

 

[Rich82]

Thanks for answering.

One more question, where would be best to fit one?

 

[cantaloup63]

The pipework under the sink just before the tap

 

[Charnwood]

Will I need to use check valves

Not if the spout is dual flow.
Some are, most aren't.

Single flow spouts, the hot and cold water mix in the tap body.
Dual flow, they don't mix until they exit the spout.