I have a baxi combi 80e boiler. I'm finding that every morning i have to check the pressure gauge. The needle always seems to drop to 0.5. Being in fear of it droping to under that. I then refill using the filling loop Only reilling upto 1 notch above: 0.5. Then a few hours later when i switch heating on ( the needle being in the same place as was after refilling earlier) the needle gradually goes up to 3. Then gradually drops down to where it should be normally. Anybody have any idea why this is happening? And what i should do about it?