New un-vented cylinder/pressurised system that is causing an issue! Help!

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Swoowoo
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New un-vented cylinder/pressurised system that is causing an issue! Help!

Post by Swoowoo »

Hi everyone

I'm looking for some thought/opinions on what could be causing issues with noise and pressure since having a pressurised un-vented cylinder installed with an Air Source Heat Pump from a traditional gravity fed system.

When it was first installed, whenever a hot tap was run there was a really loud blow torch noise/whooshing coming from the new tank.

The installers came back out several times to try different things to fix it and as one problem is resolved another appears.

1. First they installed a PRV by the stop cock and an arrester by the tank, did not fix the issue.

2. Then they piped a new feed direct to tank (I think 22mm, existing pipe is all 15mm, 80's build) removed PRV and arrester.

3. This stopped the whooshing when running the hot, and created strong hot pressure out of the tap....but now there is the loud blow torch noise when any COLD is run and a whistling noise (so, even worse as it continues for ages each time the loo is flushed!) The cold water pressure is also terrible now since this direct feed to the tank was installed.

4. They came back out today, did something, I'm not quite sure what and the noise is significantly better but cold pressure even worse.

To think I was worried about the ASHP being noisy is hilarious, it's completely unnoticeable!

Any help, opinions, advice would be greatly appreciated.
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Razor
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New un-vented cylinder/pressurised system that is causing an issue! Help!

Post by Razor »

You have gone from a low pressure system running at 0.2 to 0.5 bar to one with probably 2.5 bar on tap

It's almost certainly one of a stopcock washer, wc inlet valve, mixer tap or more likely shower valve that's giving up the ghost and letting water through when it shouldn't or passing between hot and cold.

They probably turned the flow down at the stop tap
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Swoowoo
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New un-vented cylinder/pressurised system that is causing an issue! Help!

Post by Swoowoo »

Thanks for your reply Razor, I appreciate it.
Help me understand, why would there be no noise on cold when first installed and only noise and reduced pressure on cold when noise issue was fixed on hot by direct feed to the cylinder?
What will get the cold pressure back? As now it's a trickle out of cold tap when any toilet is filling/2 cold taps run at the same time.
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New un-vented cylinder/pressurised system that is causing an issue! Help!

Post by Razor »

Is the cold feed to the taps still directly from the stopcock or have they taken it off the balanced supply from the unvented cylinders inlet valve?

When you say the pressure is awful do you get an initial burst of relatively good flow then it very quickly drops off? If so it points to a restriction somewhere in the internal pipework
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Swoowoo
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New un-vented cylinder/pressurised system that is causing an issue! Help!

Post by Swoowoo »

I believe they have taken it off the balanced supply from the cylinders inlet valve. Could this be why the noise has moved from hot to cold running water?

Before they reduced the pressure yesterday, the hot did an initial burst then eased off but the hot was still good pressure after the initial burst. I don't think the cold does an initial burst but it's so bad you can't flush a loo and run a cold tap at the same time.

The noise is coming from the cylinder but could this be generated somewhere else on the system and the cylinder acting as an amplifier?
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New un-vented cylinder/pressurised system that is causing an issue! Help!

Post by Swoowoo »

Sorry, another thing looking at your message before, would a faulty inlet valve on a shower/WC anywhere in the house cause the noise to come from the cylinder?

What do you think would fix the pressure issue if the cold does now come from the inlet valve at cylinder?
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