DIY Doctor UK DIY Forums

when the hot water/central heating system comes on,there is an initial flushing sound .this occurs for the 45 mins on and off.what sounds like water trickling can also be heard.then around 45-60 mins what seems to be gurgling or bubbling happens with then maybe the bubbling hitting one of the radiators.is there an easy way to resolve this?
so far I have bled all the radiators as instructed on my other post with all of them now working a treat.I have checked the 2 tanks (1 small.1 large)in the loft and they seem to have enough water in them.also how much water should be in them and what one does what.both have a copper pipe that goes into each of them should these bee submerged or are they like a vent and suck cold air down or purge hot air out??
any ideas on how to fix this as I am sick of being woken up by the noise
thanks for your help
danny

The larger tank stores water which feed the hot water cylinder and your hot taps, and should be full to just a couple of inches below where the ball valve supply enters.

The smaller tank keeps the heating topped up and may only have four or six inches of dirty water in it.

The larger pipes entering the top are expansion pipes, and should not be submerged, and allow an escape route for trapped air, excess water or steam should the water boil.

It sounds as if your system has either trapped air or is sucking air in. This topic has been covered in various posts recently. See topics in the central heating and plumbing forums.