Droning noise from loft - incredibly loud!

[morini66]

Hi All, hope you can help 'cos this is driving me and the better half nuts. System is open vented with Baxi Bermuda back boiler, indirect coil DHW tank and three port divertor valve. Had a few problems with pipe drone over the years, which was always stopped by turning on a cold tap. But not anymore!
Now we get a droning resonance that shakes the whole house, wakes the street and does not respond to any taps, toilet flushing etc. It seems to come from the loft, where there is a CWST plus header tank.
I went up there to check the ballcock on the header, but it seemed fine so I left it alone - after I took the face off and checked for any debris, diaphragm split etc. What I did notice was that the water in the header tank was very warm. Not sure if this is from the overhead vent outlet or from the outlet pipe backflowing. It was also too full and I baled out quite a bit.

Can't seem to pin down any timing for the noise kicking off. May be linked to the HW timings but not sure. The heating is on constant with a programmable room thermostat.

I read a few other threads here and have turned down the pump to minimum - pump is very recent BTW as is room thermostat.

Any suggestions very welcome, especially by my neighbours!

 

[Dal5band]

I've recently fixed a Torbeck valve on my mum's toilet which was making a strange grinding buzzing noize - not the usual water hammer you get from the old ball valves. Fitted a new diaphram washer.
Check if you have a Torbeck valve anywhere - loo, water tank etc.

 

[GreenArmy]

First thing, change the ball valve. Next check/replace the cylinder thermostat. If the noise persists more investigation required.

 

[morini66]

Thanks for that. Pretty sure I have no Torbeck valves anywhere.

I will change the ball valve when I get a sec and test the tank stat

In the meantime, I read on another thread that it could be due to over pumping, or somesuch name. I turned the pump down to minimum and had no noise since. So fingers crossed. But I will still check the tank for warmth, depth and I already bought the new valve so may as well fit it.

I should also re-route the overflow, as at present it just dumps into the cold water tank alongside. Which doesn't seem too healthy!

Thanks again for suggestions