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Unvented cylinder noise when hot water demand

Hi, I’ve got an unvented cylinder and over the last few days it’s started making really loud noises when there’s a hot water demand,
For example I turn the bath tap, and for around 30 seconds there’s a loud, humming or even the sound a drill makes, coming from the cupboard, and then it just stops and works as normal.
It seems to be getting louder and lasting for longer.
Any ideas what this could be?

5 Answers from MyBuilder Plumbers

Best Answer

get a g3 registered plumber to look at it.


Answered 29th Feb 2020

Hi Mattywolves

You will definitely need a G3 registered Plumber.
If you have Megaflo then the air pocket within the cylinder need periodically recharging....all you need is to discharge water from pressure relief valve into tundish until the gargling of water finishes.
If you have other Hot water cylinder then there could be other possibilities as well like sediment buildup or the water pressure is very high.
Cozy Home Improvements Ltd


Answered 1st Mar 2020

I totally agree with the other answer, unvented boilers can be dangerous if not mentained properly, get an unvented expert ASAP, Regards, Alex


Answered 7th Mar 2020

Hi it sounds like the pump is on it’s way out


Answered 13th Mar 2020

Yes to check the cylinder for faults you will require a G3 registered plumber but on many occasions I have found the problem to be s faulty fill valve in the toilet which causes water hammer


Answered 13th Mar 2020

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