Combined direct vented hot water cylinder

[Mrtoastie1]

Hi, I have a combined direct vented hot water cylinder installed in my flat and it works on economy 7. Just recently I have noticed that when I open a hot tap the water didn't come out warm and also after about 2 minutes the cylinder or pipework to it started juddering. Just in case the heating controller was having an effect I turned off the controller waited until I could hear no more water filling the tank then turned on a hot tap. After 2 or 3 minutes it started making a noise so it appears not to be heat related. Can you help please.

Read more: Combined direct vented hot water cylinder - https://www.diynot.com/diy/threads/combined-direct-vented-hot-water-cylinder.547980/#ixzz6Qe9ONdFX

 

[Aquarius]

Sounds likely to be the float valve. Do you still get hot water?

 

[Mrtoastie1]

I've turned the heating controller off because I wanted to make sure that it had nothing to do with over heated water. So with it off and a hot tap open it still rumbles after a few minutes.

 

[Aquarius]

I've turned the heating controller off because I wanted to make sure that it had nothing to do with over heated water. So with it off and a hot tap open it still rumbles after a few minutes.

Does the rumble sound like it's coming from the cylinder? A bit like a ships horn? If so, new washer to float valve or new valve altogether.