I have a glow worm swiftflow combi boiler and there is a constant drip coming from the over flow outside.
The heating still works, all radiators are fully hot, the hot water works at a decent pressure.
The pressure on the guage will slowly drop until we refill it. I think it is possible the pressure release valve that is stuck open slightly. If this is the fault are parts available for this boiler. I think it is the 100e model, but not sure, it is 12 yrs old. thanks for your help

Mark Stephens, November 2009

yes the boiler is completely repairable, fault will be the red expansion vessel behind the boiler having no charge in it, this should be pressurised with a foot pump to around 10psi, and the pressure relief valve changed.

Brucey, November 2009