noisy check valve

[james2006]

Hi - I have just installed a mixer tap. The hot is feed by low pressure gravity system (head of 6m) and the cold from mains. Despite the pressure differences the tap works fine. However I was concerned about the cold running up the hot pipe so I fitted a single check valve. The issus is that when the hot tap is just on - there is a vibration from the check valve (I assume the valve is rapidly opening a closing) - Is there any way around this - eg a low pressure/more sensitive valve?


Appreciate any help

 

[Agile]

Thats unusual but as you suggest another valve might not make the noise.

Its generally bad practice to have unbalanced supplies though!

A pressure reducing valve on the cold set at close to the static head of the hot will usually work wonders.

Tony

 

[james2006]

Thanks Tony - so step one - I shall try another check valve.

Unfortanely the whole house has unbalnced supplies as the cold is direct to every outlet.

 

[Agile]

Sorry, I should have said another design of check valve.

With a plastic plunger as they are lighter ( although few domestic valves would usually be found with brass plungers ).

Tony

 

[james2006]

Ok thanks.

I read somwhere about taking out the spring - have you done that before?

 

[spraggo]

It is unusual for the hot and cold to mix within a mixer tap as as they usually have a fluted spout to prevent this, so that the water only mixes as it leaves the spout. Are you sure that you have installed the check valve the correct way round?.

 

[james2006]

I have the valve in the correct way, I understood that the mixing takes places within the tap, in a modern tap, and that creates the risk of cold flowing up the hot. I guess I could fit a PRV to the cold and then take out the check valve?