I'm sorry if this is something that has already been answered. I have a Potterton Suprima 80 boiler. Lately my central heating wont come on but the hot water works ok. The thermostat in the hall comes on but the boiler doesn't fire up. Sometimes when the hot water and central heating is on the radiators warm up. But only when the hot water is on. I've checked out the PCB but all the solder connections look ok I've also noticed a steady drip from an overflow pipe out the back (don't know where it is coming from). It looks like it drips all night but stops in the day. don't know whether it is related to the heating problem. Would be grateful if anyone has any advice.