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Plumberpro, Plumber
Category: Plumbing
Satisfied Customers: 634
Experience:  Heating and plumbing answers. 20 years experience
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Good afternoon, I have a new external cold water expansion

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Good afternoon, I have a new external cold water expansion vessel just installed and the pipe that feeds the vessel vibrates once a day every morning when I use the shower, what can I do to stop this?
Hi , its important that all the pipe work is securely fixed with clips to prevent movement . water pressure often builds up overnight , so with the first use you will get aclittle water hammer. One way to stop this is to fit a locktight pressure reducing valve on the incoming mains pipe. This will prevent the water pressure exceeding a set level ( ie 3 bar) .these measures should do the job .
Customer: replied 2 years ago.

Hi Toby

Its not the copper pipe that is vibrating, its a silver metal flexable pipe that goes from the overflow valve ti the vessel.

Hi . I assume you have an unvented cylinder and the flexible hose comes off the combined valve .is that correct?
Customer: replied 2 years ago.
Hi , I've never known one to vibrate before . I'm wondering whether it's just a one off or it may have been fitted incorrectly. Is there any way you can upload a photo or video of the installation (all the valves and pipe work?
Customer: replied 2 years ago.
I can send you a video from my email, shall I email it to you?
OK ,***@******.***
Customer: replied 2 years ago.
Email sent

Hi . there really should be more clips on the incoming main cold , its pretty much in the air quite a bit .acceptable as long as the system has no issues , but that's not the case.. Could you just check the combined valve that the expansion vessel connects to for arrows and just confirm they are going in the right direction. Can you also check that the expansion vessel is not touching the pipework , thanks

Customer: replied 2 years ago.
Arrows all going the right way, vessel is not touching pipe work. As I say it sounds like it's filling up through the pipe but I'm not sure. The last valves diaphragm broke and it filled with water, which is why it had to be replaced.
Had a good fewc looks at the video.
I suspect your water pressure exceeds 3 bar overnight .probably why the diaphragm burst. the current pressure reducing valve must not be drop tight( allowing pressure to sneak through the valve.
You need to fit a dsrop tight pressure reducing valve o the pipe work before the combined valve and after the stopcock . it should be set to 3 bar ( comes factory set at 3 bar.
Honeywell do one that is drop tight
Shouldn't take too long to fit.
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