Thanks Daniel,
I'm not sure where a washer would go, it's just a compression nut at the moment.
Am I right in thinking that a 15 mm compression nut from anywhere else is actually a half inch screw fitting?
I wish I did so I could check myself. It was just a compression nut connected to the boiler output and 15 mm pipe - leaking from the screw connection to the boiler.
I can't get over there until next weekend and so can't get a picture until then. I'll try with just a compression nut and some...
I was doing some work at a relative's house last week and noticed that there was a drip from the boiler. It's from the hot water (taps) connection.
When I mentioned it they said it had been like that since it was installed a couple of years ago and as it was a slight drip the plumber when...