The pressure on my Baxi boiler is too high and the release valve keeps opening. When I switch a tap on (cold or hot), the pressure goes down. When I switch the mains water off, the pressure goes altogether, and - even though the feeder tap is off - the system refills itself when I switch the mains water back on!

For a while, the system wasn't working at all (the radiators weren't getting hot), and it turned out the filter in the boiler was clogged with rust. After cleaning the filter, the radiators now work, but I'm getting rusty water from the taps.

Something ain't right, that's for sure, but what is it?

Starlinguk, January 2009

yup id second that one, new heat exchanger

Jazz drummer, January 2009

The plate heat exchanger must be split internally. This would explain your boiler filling itself and also the rusty water from the tap is coming from your heating system.

boiler man, January 2009

Additional info: it's a combi boiler, running on gas.

Starlinguk, January 2009