Kitchen mixer tap gravity hot water mains cold

[Fallout]

Is a check valve required on both feeds to a kitchen mixer tap ifView media item 96252View media item 96252 feed from gravity hot water and cold mains.

 

[Fallout]

Or just the hot?

 

[Fallout]

I don't think the tap is dual flow

 

[Madrab]

If you're following the water regs then you would have a single check on the cold mains.

You may find you have hot water issues though if it's a single flow (mix in the body) tap if the hot n cold supplies aren't balanced.

 

[Fallout]

Would one not be needed on the hot to stop the mains over powering the hot and going up the hot pipework?

 

[ScottishGasMan]

Its two seperate handles so no need for a check valve on either.

 

[Fallout]

Thanks, why does it having two handles mean it doesnt need a check valve either side? if you just put one on the cold could the mains not back fill the hot water?

 

[bernardgreen]

If it is a tap used for drinking water ( including water used for cooking ) then it MUST not mix hot and cold in the body of the tap. There must be two channels through the spout so that hot and cold cannot mix together until falling under gravity clear of the tap.

 

[Madrab]

Regardless of whether you have check valves or not, if the cold pressure is much higher than the hot, it will restrict the hot flow if it is a single flow mixer tap, it may not flow up the hot pipe with a check valve but it can stop it flowing into the tap body so it makes no difference, a check valve will also restrict gravity hot water.

As bernard mentions though, if this the only mains cold fed tap in the property, it needs to be dual flow or 2 separate taps to ensure no contamination of the drinking water from the hot.

 

[Fallout]

Thanks thats the tap in the picture, the spout is just one channel so pretty sure it mixes in the tap body, any one come across this tap before? Was meant to be for a kitchen sink

 

[Fallout]

Is it not suitable for a kitchen sink then, think its designed for a kitchen sink

 

[Madrab]

It's not that it's not suitable for the kitchen sink, it's just that ideally you would have at least one tap in the house that supplies mains cold water that can't be mixed with the gravity hot water, to supply the drinking water. That's usually the kitchen sink in a gravity fed system.