Well, just in case anybody's interested... heating guy came today to do the annual service, poked around a lot with his gas analyser, and found it wasn't leaking from that pipe at all, but from the seal where the flue connects to the boiler - so of course it's CO leaking out.
Fortunately it's nice and warm here for a change, so the boiler isn't on - he's ordered a new seal, but thinks it may be a bit of a job getting the flue up and out of the way to fit it. Let's hope not...
Fortunately it's nice and warm here for a change, so the boiler isn't on - he's ordered a new seal, but thinks it may be a bit of a job getting the flue up and out of the way to fit it. Let's hope not...
