Singing Mixer Shower

[steven9586]

Ok, I have a Mira Realm mixer shower that's singing it's heart out. It only starts to sing when the hot water starts to come through from the Combi boiler but is fine when it's cold before the hot water arrives.
I'm going to fit a PRV as I've turned the stopcock down as a temporary measure to prove it's high mains pressure that's causing it.

My question is, Do I fit the PRV after the stopcock and drop the whole system down to 3.5bar or fit it on the hot water inlet only to the shower? Thoughts on this, is that I'm not 100% if it's the hot or cold side that's causing the noise as it's a combi system but presume it's the hot due to the fact it only starts when the water gets hot.

Thoughts guys.

Cheers Steven

 

[oz-plumber]

Personally, I would be looking at the boiler.

If the noise only starts after the water is coming through hot, then I would doubt it would be a tap or pressure related problem.

 

[Sparkgap]

What's your existing mains pressure? When the valve is cold its taking all the flow from the hot side which should be at lower pressure having gone through the combi. As it gets warmer it takes more from the cold side and if you've a small gap as the valve opens and high pressure that can give you noise. If you're happy with 3.5 Bar throughout the house then fit it after the stopcock. If you only want the shower then fit the PRV to the cold.

 

[steven9586]

Oz, It's not the boiler

SparkGap, I'll check the pressure tonight, I didn't think about all the water being fed through the hot first so it must be the cold. What's your thoughts on 3.5bar throughout the whole house as it will be much easier to put the PRV after the stopcock, as I will have to lift carpets and floorboards to fit it on the cold feed to the shower.

Cheers

Steven