high pressure problem british gas C1 combi boiler?

OK, I've found it. A silvery connection between a cold pipe and a warmer pipe going into the boiler. (This is with the boiler on and functioning hence it being warm).
Am I right in thinking I have to unscrew the large 'wing nut' type taps at both ends of the flexible piping to allow the water to flow through in order to top up the boiler?
Also, do I have to switch the boiler completely off to do this or just the heating (making sure we don't turn on the hot tap as well).
I'd appreciate any tips!

karina
March 2009

Not an answer I'm afraid but I've the opposite problem. My pressure is low. I suspect the 'filling loop' - but should that be something pretty obvious? Are there any pictures online as we inherited our boiler and the plumbing in the house is a little 'idiosyncratic' to say the least.

karina
March 2009

Thanks for that guys been told also that it could be the heat exchanger seal which allows CW pressure to feed into central heating side causing it to over pressurise

Mr S
March 2009

If its OK when the water is turned off it is almost certainly the filling loop valve passing, if external remove the braided hose to check, if you have the inbuilt filling loop remove the white key from underneath boiler to check.

Mick A
March 2009

The expansion tank is a likely cause.

Ben
March 2009