I have a Ferroli Optima Combi boiler and sealed CH system that's been running pretty well for at least 6 years. However, on start up after this summer's shut down I have a pressure problem (hot or cold, on or off) which means having to top up twice a day. Now, I've cured a few minor valve joint leaks, and there's no water being expelled out of the pressure relief valve and no water that I can trace anywhere else, but I'm still having to top up. The situation's driving me nuts.

Any ideas please before I pull all my hair out? I can't see a problem with the expansion vessel - although I have taken a couple of rads off for decorating. Could this be the problem?

Agrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr rrrrrrrrrrrrrrrrrrrr

Thanks in anticipation