Noisy Combination Valve

[*Dan*]

We have an unvented hot water system (megaflo) on the first floor of our property and have noticed what I can describe as a clunking noise coming from the 3 bar combination valve. This happens when the cold water is shut off on a tap (not hot water) and is more prominent on the bath taps (22mm feed as opposed to 15mm on everything else).

I have looked into the heatrae sadia combination valves and will get a g3 to change it but not sure if you need to change the whole valve or if you can change just the cartridge (which is the half the price of a new valve and less labour).

I have a video of the noise this is making below and just wanted to see if its normal or not? It seems to do it worse with the washing machine on at night and initially I thought it was water hammer so purchased a damper to go on the back of the washing machine but didn't do anything.

thanks for looking

 

[Madrab]

Yup, any clunking/clicking coming from the valve will probably be the PRV. Yes the cartridge on it's own can be changed but remember that everything else in the valve is the same age so may be better just changing the whole valve.

 

[*Dan*]

Yup, any clunking/clicking coming from the valve will probably be the PRV. Yes the cartridge on it's own can be changed but remember that everything else in the valve is the same age so may be better just changing the whole valve.

Ok thanks for that I think it has been getting worse slowly after the last year or so. If I put my hand on it I can feel it almost sticking when the noise happens.

I’ll get someone change it - just trying to work out roughly how long it would take to do? I Don’t think you need to drain the tank by looking at the arrangement on my setup - should be a case of shutting off the cold to the valve below it and changing it over.

 

[Madrab]

You will need to drain the tank down to the level of the valve. The minute you release the upstream part of the valve the cylinder will start to empty. There should be a drain valve fitted on the cold feed to a drain point.

 

[Madrab]

Oh and can't see/hear you video without signing in.

 

[*Dan*]

You will need to drain the tank down to the level of the valve. The minute you release the upstream part of the valve the cylinder will start to empty. There should be a drain valve fitted on the cold feed to a drain point.

The valve in question is the pressure reducing valve upstream of the tank itself and sits above the water cylinder. It’s reducing the mains pressure down to 3bar before the hot cylinder.

My PRV seems fine on the tank itself though 1 there doesn’t seem to be any knocking when the water is switched off.

Oh and can't see/hear you video without signing in.

Just tried changing the settings should work now

 

[*Dan*]

here are some pictures of it

 

[Madrab]

Yes, I am aware what the PRV is. If the valve is set above the cylinder with a stop valve downstream then that should be fine, not all are installed above the cylinder.

Your G3/UVHW qualified engineer will know what to do.

 

[*Dan*]

Yes, I am aware what the PRV is. If the valve is set above the cylinder with a stop valve downstream then that should be fine, not all are installed above the cylinder.

Your G3/UVHW qualified engineer will know what to do.

Yes will get in touch with them at some point to replace this.

Should have probably just zoomed out on the photos to show exactly where it is to make it clearer where it is. Thanks for your help with it.