Are we talking pressure jet or vapourising appliance here?
Vapourising (unfortunately, given your area of expertise).
[automerge]1570688570[/automerge]
Just had the whole lot out again, re-fitted everything, changed wicks etc. Still the same smell. Seeing as there's some ambiguity I'll just clarify a few points.
It's a vapourising oil burner - two channels and a central chamber with a lid, wicks in the rings, large perforated rings sitting between the wicks. all this in a converted 1969 Rayburn Royale.
Most importantly (which seems to have been missed by a couple of respondents) the smell was completely absent the day before the service, then arrived (badly) the day I re-lit it. It's been serviced to a greater or lesser extent (we've tried different things each time) six times since. The smell got slightly better the first time, then it's stayed the same since. So without any further explanation as to why...
It's not the flue - how could the flue suddenly become blocked coincidentally on the same day I happened to be servicing it? (not only that, but I've tested it with lit newspaper and it draws fine)
It's not the seals - I could have put things back wrong once, but all six further occasions with two of them not even me doing it, especially when no such thing has happened on the previous 12 times I've serviced it. Again, if the seals are at fault it would have to be an astonishing coincidence.
It's not oil the levels - the adjusters on both the oil control valve and the burner are completely rusted, the relative levels are exactly the same as they've been (probably for the last 20 years!). I've also checked and timed the oil supply rate.
It's not the wicks - I've changed them to no effect.
It's not the oil itself - Same as the others, it was fine the day before the service, bad after. Same oil.
It's not the rings or the chamber lid - I've checked both are seated completely flush and down to bare metal where they meet. Also, again, the same procedure I've done twelves times in the past and now got wrong six times times in a row, doesn't make sense.
It's not leaking oil anywhere - I've had paper towels down, as advised, around the whole burner unit and pipework for nearly an hour with it full (but unlit). Not a drop of oil anywhere but inside the burner itself.
The only thing that I noticed during this last test, it that the oil kind of wicked outside of the chamber and channels of it's own accord. Just like if you made a cup out of paper, oil would sort of wick up the sides beyond the fill level. That's what the oil was doing, it was like the burner was made of paper (rather than cast iron) and the oil was sort of 'seeping' through it. Just a little bit so that the i could see a damp mark on the outer edge. I don't know if this is normal, however, nor do I have the faintest idea what might cause it that would tie in with the fact that this happened after a service.
I'd be really grateful for any ideas, but please don't just suggest I get an engineer in. I may well do so, but there are a finite number of things that can go wrong, with a finite number of causes. If none of the experts here can even suggest something that might actually cause this problem (given the history I've outlined above) then why would an engineer who comes to see it suddenly be able to think of something? I just need some ideas, even if I just pass them on to an expert I employ to fix them for me.
