Oil fired Rayburn persistent fumes after service.

[Isaac]

it needs to be removed and visually inspected. WARNING this is a safety critical mechanical part and if not replaced correctly could flood the burner.

Sounds like my cue to get an expert in. I'm loathe to do so because I've had such bad luck with them in the past, but if you really think there's no further diagnosis that can be done without checking that first then I'll see if I can get someone in to do it and we'll go from there (pessimistically doubting I'll ever get the problem fixed!)

Thanks for all your help so far.

 

[SJB060685]

I'm not saying the metering stem is the problem, I'm saying it could cause problems like this but care must be taken when examining and positioning. The fact you said there seems to be a pattern makes me think it could be a fuel delivery problem and the metering stem should be checked in these circumstances, along with filters, fire valves, fuel flow etc.

 

[Brambles]

Issac,

There are a number of key issues other than oil depth in the well that can / will result in burner popping:

Wrongly positioned wick
Not enough primary air
Too much secondary air
Insufficient flue pull
Vaporiser not properly seated / sealed

Additionally flue downdraft - mentioned by an earlier poster can exacerbate burner popping.

If you consider wooshing in conjunction with popping the obvious causes (other than oil level and flue downdraft) is:

Oil feed is being heated before it enters the burner - insulate the oil feed line.

The best route forward is to remove and rebuild the burner system, checking each of the key points - very often with atmospheric burners, the issue is more than the resolution one specific problem.

 

[SJB060685]

As Brambles has said Issac your best bet would be to strip and start again checking all points.

He says above and I believe I read in earlier comment which is why I didn't mention it is the wicks need to be cut correctly and positioned so gaps line up with channel holes, failing to do so can cause problems you're experiencing, it could also cause the rings to loose flame, only to catch again when enough fuel has seeped through, I've even had to use a match to ignite the outer ring again when it doesn't catch.

Oil depth we've been through.

Combustion air we've covered.

Flue pull we've discussed and I believe you said chimney is sound.

Vapor plug I mentioned as I did an anti down draft cowl.

He mentioned the burner feed pipe (the 6mm carbon lag that connects to burner base) it's not unheard of for these to get too hot and start vaporizing inside, that's undesired and the way round that is to insulate as suggested. Some tin foil will do it to direct heat away, I've also know some older engineers fashion a sturdier piece of metal to place over.

Everything else I think we've covered between us.

 

[Isaac]

The best route forward is to remove and rebuild the burner system, checking each of the key points - very often with atmospheric burners, the issue is more than the resolution one specific problem.

As Brambles has said Issac your best bet would be to strip and start again checking all points.

Thanks guys, for such an exhaustive list. It'll be a few weeks before I can get round to such a large job, but I think I might have to give up (again) and call in a third engineer. The trouble is, I don't know what I'm looking for, nor how to stop these problems from recurring. You see, I've done most of the tings on your lists already. Some i do as part of the service (the very thing which started this whole problem), some I've done in response to the problem (I've effectively re-serviced it five times now since this problem began, with no long-term effect on smooth running).

If I go through the list I don't think I'm really going to be any the wiser, nor be in any position to prevent this from happening again.

Wrongly positioned wick - I've replace the wick five times in this whole saga to no effect, plus the latest problem simply occurred out of the blue one day, so - a) I'm suddenly putting the wicks in wrong after six years of doing it right - in which case I need to know what I'm doing wrong, and b) how do I tell I've put then in right when the burner runs fine for weeks before going wrong?

Not enough primary air - I've no idea what I'd be looking for here, nothing about my kitchen ventilation, nor the chamber inlet has changed to my eyes. I have a ventilation grill in the wall next to the burner (which isn't blocked and is never closed) and the inlet is always fully open and never blocked (I don't have pets), so - again I don't know what I'm looking for if this could still be a problem.

Too much secondary air - Not sure what this is.

Insufficient flue pull - I've had the flue swept, and the restrictor plate is the same one that's been in place for the last six years. So, again, if a set up that's worked for six years can suddenly not work, I kind of need to know why that might happen and prevent it, otherwise I might fiddle with the restrictor plate, only to have it go wrong again in a month's time. Or, if there's more to flue pull than just the restrictor plate and the flue being swept, then I need to know what I'm looking for.

Vaporiser not properly seated / sealed - as with the wicks, the vapouriser has always been fine, it's been out cleaned re-seated and replace five times to no avail. If it's broken beyond repair then there's no point in me getting it ourt and putting it back a sixth time without changing anything, but at nearly £500 to replace It would be really great if I had some kind of sign that it was broken, something I could see had snapped/cracked/bent whatever. same with sealing the plug - why would it need sealing now,, all of a sudden There's no sign of wear that I can see. If I get a replacement, how do I know the same thing won't just happen again in a month if I don't know what caused it to happen this time?

Additionally flue downdraft/Anti down draft cowl.- Nothing has changed in my flue set up, so what would I be looking for if flue downdraft were a problem, presumably something which used to stop it all the last six years of perfect running has broken, but I don't know what I'm looking for - the restrictor plate is the same, the flue is the same and the flue cowl is the same - are there any other components?

Oil feed is being heated before it enters the burner - same as the others. How do I prevent this from happening again if I don't know what caused it to suddenly start happening now? It's obviously not been heating the oil feed for the last six years. It wasn't heating the oil feed a few weeks ago (before this crackling noise started). If it now is suddenly, without me touching it, heating the oil feed, I need to know what might have caused it to do that so that I can stop it from happening again, yes?

Oil depth - I check the oil depth at service and it's been fine for the last six years, so - either my checks are suddenly inadequate (does the right oil depth change over time?) or something has happened after service which has disrupted the oil depth - in which case I need to know what that thing might be, so I can stop it from just happening again a few weeks after I've done all this work.

I really am at the point of giving up and ripping the whole thing out. You guys have shown more technical know-how in your posts than all the engineers I've had out put together despite them being able to look at the thing directly, but no-one seems to be able to pin down the crucial question - why has this suddenly started happening now? What did I do in that service (and fail to fix in subsequent five re-services) which caused things to go so irreparably wrong? What suddenly happened a few weeks ago that turned a fairly functioning burner into a non-functioning one despite nothing visible having changed?

I really appreciate all your help, but I'm at the end of my tether and the thought of doing another full service, just like I've done five times before, and it having no effect (again!) is not one I savour, nor is the thought of paying someone, to fail to fix it (again!). Still - it doesn't sound like I have a choice, so maybe in a few weeks I'll be back here badgering you again after another failed service!

 

[SJB060685]

Hi Isaac.

Firstly I just want to apologise that Brambles or I haven’t been able to give you a quick fix, as Brambles said these burners can be problematic and often there is more than one culprit.

Wrongly positioned wicks: as I said these should be cut to size and positioned over channel entrances. Like you said you’ve been doing this for years without a problem, so I doubt it’s the culprit.

Not enough primary air: if you’ve never had a problem until now and you’re adamant nothing has changed ie, no blockages etc then again I doubt that’s the problem.

Too much secondary air: I thought there was only a secondary air duct for solid fuel cookers, perhaps @Brambles can elaborate?

Insufficient flue pull: if you’ve had the flue swept etc then again this probably isn’t it, however to test the pull the cooker needs to running and flue hot to get an accurate reading with the right tool. Can’t tell you the exact figure you’re looking for but flue draft is a negative pressure, too small and the pull is weak keeping heat inside the chamber which could cause vaporisation in the mentioned carbon leg, if really bad then I’d expect fumes to be escaping into room as there is no pull. If the pull was too high then most of the heat will be pulled up through the cooker before doing its thing and a flue draft stabiliser is often used on other appliances. With an oil cooker on a conventional flue you want a minimum effective height of 5 metres, obviously the taller the flue, the hotter the flue gasses and the colder the outside air the better the pull. Having said all that you say all is sound and if it’s only just occurred in the last few weeks then then flue probably isn’t the problem.

Anti downdraft cowl: I’ve known systems fine for years and then in high winds without an anti downdraft cowl and/or wrongly terminated flue to start experiencing problems, again a draft reader will show this but again from what you’ve said I suspect this is ok.

Carbon leg vaporisation: this happens when there is too much heat surrounding the carbon leg, the oil starts to vaporise within the carbon leg and not where it’s intended to, in the rings. This can be caused by poor flue pull etc. One way around this is to insulate the carbon leg with some tin foil to direct heat away.

Oil depth: these burners have a theoretical and practical oil depth of between 4-5mm, other burners are different but irrelevant to you. When servicing this depth should be checked and the burner checked to see if level with a two way level. Over time these could alter.

A few weeks ago it was quite cold and if oil lines are exposed to the elements, without being insulated then the oil can wax up, this happens when the paraffin content starts to crystallise. I have had situations where this happened and we had to check/clean all filters and remove any crap that causing a fuel delivery problem. You say there is not a problem and if the cooker is up to temp then this reinforces that idea, however I would still check for fuel delivery as everything else has been checked.

Again I’m sorry I don’t know the definitive answer right now.

 

[Isaac]

Firstly I just want to apologise that Brambles or I haven’t been able to give you a quick fix, as Brambles said these burners can be problematic and often there is more than one culprit.

Not at all, you've both been really helpful. Even if it hasn't fixed my problem I've learnt loads which I'm sure will be useful to me in the future.

One last thing before I resolve to start again - am I right in thinking if there wasn't enough oil getting through, a ring might go out, only to re-ignite once it had got saturated enough?

I'm just trying to get my head round flow rates and levels - the flow rate determines how quickly oil is replaced, but the float in the OCV (it's height relative to the burner rings) controls the level of oil, is that right?

So my leading theory at the moment (odd though it sounds) is...

I broke something on my burner during the service that started this all and that caused the fumes smell, but there was also something slightly wrong with my draw (though not enough to cause any problems before). Fixing my draw meant that the fumes from my broken burner went straight up the chimney so they no longer bothered me (but the burner was still broken). A few weeks later some build up of stuff (carbon, wax, muck...) meant that my broken burner starts crackling and whooshing because the oil levels aren't right.

So - I need to fix/replace the broken burner (for which I'll need to know what's wrong with it) but in the meantime if I clear out the carbon/wax/crud that's messing up the oil levels, I might get it back semi-working again until I get a replacement.

It all sounds like an astonishing set of co-incidences, but theses things do happen.

Anyway, thanks again for your help. The burner has mysteriously stopped crackling now - despite me not even touching it), but it's still whooshing so I just need to get a few days clear to re-service it.

 

[SJB060685]

Yes the level inside the OCV is governed by the floats. The burner is set up to have a depth of around 4-5mm, this is done by adjusting the burner height so there is this depth and of course level at the same time. The level of oil in burner will equal to the height of fuel in the OCV.
The flow rates is as you said how much fuel flows per minute, low fire around 4 millilitres or cubic centimetres and high about 8 but each cooker and burner is different, flue pull etc can all affect the required flow rates, a good pull might mean slightly higher flow rate to compensate and a weaker might need less and some other burners have different oil depths like I said earlier but this is irrelevantto you.
Yes the rings can loose flame. This can be caused by wicks blocking channels or carbon doing the same. Inadequate fuel flow will also cause this and If the flue pull was too great the flame could lift off as well causing the same.

 

[david0908]

Hello Isaac. I just found this thread - I have had similar problems .... started at the beginning of your story and got hooked like a good novel .... and then nothing!!! What happened? Please tell us? Did you buy a new burner? Or break it up with a sledgehammer? Or did you find the fix?
My story is v similar and too long to tell- the short version is OCV filter was completely clogged - since I sacked the engineer who allowed this and took over things have been much better except it is a little bit smelly. Flow rates were completely off after cleaning filter as he had been adjusting them to compensate for the blocked filter. Smell was really bad and flue cleaning helped quite a lot, and I found that the 10mm oil supply line was pretty badly clogged up as well so had that cleaned out. So today its pretty good except a slight smell which it never had before.
Other things that happened to me ....

• the oil feed pipe to burner lifted the burner slightly so not level - do double check this and bend down or rotate to lowest position;
• oil feed pipe unions leaking slightly - sorted with Heldite jointing compound

Anyway, I have identified an engineer who is a bit of a legend and he is coming to look in a few days so fingers crossed as I have given up trying to figure out the problem that is causing the smell.