Oil fired Rayburn persistent fumes after service.

[Isaac]

I've been servicing my own oil fired Rayburn for years without any problems. Immediately after my last service, a few days ago, it smelt really fumey, stank the whole house out. It also would have regular (what I call mini-explosions - it's not that dramatic, but I can't think of a better word, a bit like suddenly going from low flame to full flame for a second). I thought that oil vapour leak would be the cause of both issues (thought maybe I'd put something back too loose), so I had the burner out again, made sure the chamber lid and rings were flat on, checked for oil leaks, put everything back.

That solved the mini-explosion problem entirely. I now have a smooth, entirely blue flame without so much as a splutter. But the fume problem is still there, even possibly a bit worse.

Fume smell is the same on low or high setting (so I'm presuming oil levels can't be a problem (not that I didn't check the levels anyway). The smell is coming from the door as much as the hotplate, so It can't be seals (there's no seal on this model's door).

All the usual culprits of fumey smells I've read about seem to be to do with the rayburn needing a service, not a consequence of it getting one. Other culprits such a chimney blockages, fuel filter clogging etc., I can't see any way they could have just suddenly come about as a consequence of a service. The day before the service it was fine.

Any clues as to where to look next would be much appreciated.

 

[Isaac]

Firstly, don’t be tempted to use exhaust paste on the burner shells - they are virtually impossible to clean properly after it has been applied.

Good, that was my gut instinct too, sounded too much like a bodge to me.

I don’t normally like to propose trial and error solutions - but it may be worth trying the range without the restrictor plate in place, or if you can with it partially removed.

I've added some extra rope seals, just to keep the unpleasant smell down whilst I experiment (and until the chimney sweep gets here). They seem to be working. Another windy day and again the smells went away. I don't know though whether that's how the burner normally smells and its the flue not taking the gases away that's the problem, or whether there's something wrong with the burner and having a more effective flue is just masking the problem. Anyway, thanks again for all you help, it's been invaluable.

 

[Brambles]

Isaac,

I think that you have two issues, worn set if burner shells and a flue that has probably slightly light on draw.

If you can improve the draw on the flue by increasing the holes in the restrictor plate you will get a resolution. If the draw is too great you will see the flame picture change - so reduce it and / or slightly increase the oil drip rate.

Not much you can do with the burner shells as they wear (just nurture them) better to put your efforts into sourcing a spare burner set.

If it is any consolation, I spent six hours yesterday afternoon, fine tuning a flue with a restrictor plate on an Aga after it (the flue) had been disturbed during cleaning! They are very sensitive creatures! Had I not know the owner well, I would have felt embarassed.

 

[Isaac]

I spent six hours yesterday afternoon, fine tuning a flue with a restrictor plate on an Aga after it (the flue) had been disturbed during cleaning!

Oh no. If it took someone like you six hours to get it right, I should be reporting back sometime next year!

 

[Brambles]

Isaac,

Hold your shape and keep your chin up! This is all about being logical, patient and learning about the vagaries of “the machine”.

In my view, you are pointing in the right direction - and will get there.

There will be a local expert in atmospheric burners who is much better than I am - but they are quite rare (knowledgeable atmospheric burner people) - not people who are better than me! -

From our correspondence, you seem to have a very good understanding of the principles - please continue to share your issues - we will get there in the end!

If it is any consolation, I make excellent friends with very old Aga’s (sorry not Rayburn’s) - but no profit - because they always take so much longer to resolve!! Their offspring have conventional oil or gas heating systems - so that keeps me solvent!!

 

[Isaac]

Isaac,

Hold your shape and keep your chin up! This is all about being logical, patient and learning about the vagaries of “the machine”.

In my view, you are pointing in the right direction - and will get there.

Thanks for the encouragement!

please continue to share your issues - we will get there in the end!

OK, the latest oddity. I think the inner wick isn't lighting (or not as it should anyway). When I look to check the flame colour (as I do each time I've relit it) I can only really see flames coming from the outer ring, it's not very easy to see the inner ring, so I wasn't sure, but that's what it looks like. Then today, I went to re-light it (after a flue tweak) and a strange thing happened. I accidentally got the timing wrong for letting the burner fill, I usually wait 15mins, but this time I ended up only waiting just under 10. Anyway, I dropped a match into the inner ring, nothing happened. I looked at my watch and realised my mistake, but, just for the hell of it, I dropped a match into the outer ring. It lit up with a full flame immediately.

Am I mad for thinking this all points to the possibility that my inner wick isn't lighting? Could the unburnt fumes be coming from there, could that be what the 'explosions' were early on (it suddenly catching)? Is it even possible for the inner ring to remain unlit when the one just outside of it is on high flame? On the one hand it sounds like it would explain the symptoms, but on the other is sound just implausible on the face of it? I mean, for a start oil has to travel through the inner ring to get to the outer one, right?

 

[Brambles]

Isaac, that is not unusual on vaporising burners - the inner wick will light when the burner door is closed and the combustion air is being drawn.

You are correct, the oil flows to the inner burner first.

 

[Isaac]

Isaac, that is not unusual on vaporising burners - the inner wick will light when the burner door is closed and the combustion air is being drawn.

You are correct, the oil flows to the inner burner first.

Ok, thanks. So not that then. My logic being...

You're saying if there's oil in the inner ring, the wick will light eventually presuming there's enough air flow.

So in my case...

There has to be oil in the inner ring because there to be oil in the outer ring (and in order for me to forward it as a reason for the fumey smell). There has to be enough air flow because my outer ring flame is blue. Therefore my wick must be alight (it has both oil and air flow), I just can't see the flame properly for whatever reason. Does that sound right?

I'm taking it out again today and I'm going to really get all the seating of rings and chamber lid as flush as I can, tweak the restrictor plate a bit, and see what happens.

 

[Brambles]

Your interpretation with the burner rings is correct. When the burner door is open, you do not get the see the same burner flame picture as it is in use with the door closed.

You can test this if you wish by marking the inner wick - then putting the range into operation.

 

[Isaac]

Your interpretation with the burner rings is correct. When the burner door is open, you do not get the see the same burner flame picture as it is in use with the door closed.

You can test this if you wish by marking the inner wick - then putting the range into operation.

OK - the Rayburn's been fine (almost) for the last couple of days. I took the restrictor plate out and realised (I think) it had a particular 'way round'. a way it has never been (I rent this place), but a way which is obvious once it's but like that, it fits the flue outlet perfectly, which it never did.

Anyway, I put the restrictor plate back the right way round, but the smell persisted. then I closed the bottom chamber door properly and the smell went away, has been like that for days now.

So - to explain the bottom door (the one where the burner sits (where I presume the ash pan used to be when it was solid fuel) - One of the engineers I had out when I first moved in told me that these rayburn conversions need a lot of air and to leave the bottom door open a crack to help supply them. I've always done so and it's never been a problem, but then the restrictor plate's never been on right either.

So, is it possible that the restrictor plate and the air inlet have to be kind of 'matched' to get the air flow right? That fixing the restritcor plate was the right thing to do, but it needed the air inlet to be fixed too to match it? Or have I just made myself another problem by not giving the flame enough air? I'm really reluctant to touch the whole set-up now as it seems to be working fine.

 

[Brambles]

Well done!!

In essence, the starting point is to ensure that the draw in the flue is sufficient (-1mm H2O) if you have the ability to measure it - that will ensure that products if combustion are drawn away and that combustion air is pulled.

As long as the room the range is in is adequately ventilated you will always have sufficient combustion air to feed the burner.

The burner door should never be left open - it should also be adequately sealed. The range draws combustion air from the low level vents up to the burners. If the door is open, this flow is interrupted, but far worse is the danger of any blow back from the burner - the burner door is there to protect you and the kitchen in the unlikely event of that happening.


The above us also why it is difficult to assess the flame picture, because when the door is open the burner is not in its steady state. In an ideal world the burner door would have an inspection window.

So for improving the air flow, you modify the restrictor plate - to do this, make a second restrictor plate - a copy of the first in thin sheet steel and make slight modifications to see the impact. Once you are happy with it, copy the mods to the original restrictor plate.

You are trying to get a draw that gives you a dull red surface to the burner with a blue flame ( no yellow) immediately above it. Too much draw and the flame will start to lift off the burner.

In reality on an old stove, it will always be a compromise - but it looks like you have already achieved that - and now have a good knowledge of the idiosyncrasies of the range.

Personally, I would not use the engineer again who suggested leaving the burner door slightly open. Normally after conversion from wood (or solid fuel) to oil, you want less not more combustion air.

If it is any consolation, I am really struggling at the moment to get an Aga that I have converted from oil to biomass chips to perform reliably. A nightmare!!

 

[Gavla7]

Hi , I’m an oil engineer and the only thing i can say has the oil line been pressure tested?

 

[Isaac]

Fumes have been gone for all this time and remain gone, but...

The burner has started 'whooshing' again. I can see through the air inlet it's a sudden burst of bigger brighter flames, only lasts a second, like some reserve of fumes/oil are suddenly being ignited.

Plus, the last few days I've had this 'crackling' sound, like the noise you get when a roast is in the oven (the tiny globules of fat hitting the metal oven walls).

As mentioned earlier in the post, it's only a short while since its last service.

Obviously can't get an engineer out over the holidays, so I'm just wondering if any of you guys might be browsing here on your days off.

Hi , I’m an oil engineer and the only thing i can say has the oil line been pressure tested?

No, but there's no drips of oil anywhere.

 

[SJB060685]

Haven't read all of the above comments so forgive me if this has been mentioned. How thorough were you when you serviced it last. It could be a partial blockage again. Did you put fire cement around well plug? Did you check oil depth when serviced?

 

[Brambles]

Wooshing on an atmospheric burner is often intermittent combustion air

 

[Isaac]

Haven't read all of the above comments so forgive me if this has been mentioned. How thorough were you when you serviced it last. It could be a partial blockage again. Did you put fire cement around well plug? Did you check oil depth when serviced?

I service it myself and I'm not an expert, so I could have missed something but I'm usually very throrough and I haven't had any problems the past six years I've been doing it. I did check the oil depth, but I've never put fire cement around the well plug, it's never been a problem before. Should I do so now, do you think?

Wooshing on an atmospheric burner is often intermittent combustion air

Interesting. I can't think of any cause though. Could it be the flue again?

 

[SJB060685]

What Brambles is suggesting is maybe you have a problem with air supply to burner. If you have pets or anything else that could restrict airflow and/or oil flow into burner then you could experience problems.
Some well plugs are a good deal and don't need fire cement, others require to be sealed, you want the oil flowing into channels and each ring before it vaporized and ignites, if vapor is escaping from plug you could potentially have a whooshing or similar noise when it ignites as well as sooting up etc. The reason I ask what the oil depth was is because if it's too high ie, not 4 - 5 mm but more then the burner can cause a crackling noise which I believe you mentioned above.
Do you have an anti down draft cowl fitted, also do you have more than one oil appliance, in particular two off of same supply line and filter?
I would not turn off your cooker now to fire cement the plug, by the time its cooler enough to work on and safely re light it might not be up to temperature in time for your Christmas roast tomorrow.

 

[Isaac]

What Brambles is suggesting is maybe you have a problem with air supply to burner. If you have pets or anything else that could restrict airflow and/or oil flow into burner then you could experience problems.

No, nothing at the inlet end.

Some well plugs are a good deal and don't need fire cement, others require to be sealed, you want the oil flowing into channels and each ring before it vaporized and ignites, if vapor is escaping from plug you could potentially have a whooshing or similar noise when it ignites as well as sooting up etc.

The odd thing here is that this all started after a service. The day before, it was fine, immediately after, these problems started. Makes it hard to put it down to anything like wear-and-tear, or bad components. On the other hand, it does sound exactly like what's going on ( I've even seen through the inlet a sudden lighting up of the chamber as a big yellow flame ignites and then it's gone, back to blue/red glow again seconds later). Is there any way you can think of that vapour could be escaping that one single service could have caused? I've checked and triple checked the pipe joints, scraped all surfaces back to bare metal etc. I'm convinced, from what you guys have described, that vapour escape is my problem, I just cannot seem to find an explanation which ties in with the fact that it was fine one day and seemingly irreparably damaged the next.

The reason I ask what the oil depth was is because if it's too high ie, not 4 - 5 mm but more then the burner can cause a crackling noise which I believe you mentioned above.

I can't imagine there's a whole range of things that can cause the exact same noise, so let's presume it's oil too high. The problem is 1) it just started the other day out of the blue, I hadn't touched anything, so we'd have to explain how the oil suddenly got too high, and 2) ever since I moved in both the burner feet and the oil control valve feet have been rusted solid. There is absolutely no way of adjusting the oil level, which means whatever the relative valve-burner level was when it was working fine for the last six years, that's what it is now. Odd thing - if this means anything - the crackling noise goes away for a few seconds after one of the whooshing ignitions.

Do you have an anti down draft cowl fitted,

No, but as above, I never have had an anti down draft cowl and it's been fine these past six years. Is there some problem not having one could cause?

Thanks for your time.

 

[Brambles]

Isaac,

I would go back to the posts of last October and set up the Burner again from first principles. Check that the flue restrictor plate is correctly sized and installed and that all the combustion air vents are clear and free flowing.

In your last post you indicate that there are adjustments that you cannot make. What are these? To set up a vaporising burner as a minimum you must be able to thoroughly clean off carbon deposits ensure that the oil feed tube is clear and clean and be able to make adjustments to:

Level the burner.
Adjust the max and min oil flow rates (and accurately measure them at each setting (aprox 10cc and 3cc for a Stanley))
Measure the oil level at the burner (circa 4mm) and ensure it remains stable.
Wick is fairly tolerant, but the v side cuts really need to be correctly sized and positioned.

Burner picture should be a blue flame over a dull glowing red burner. No (or minimal) yellow flame.

Flue needs to be clear and have the correct pull.

As previously stated - rather than service the burner of an older vaporising range (which by their nature are temperamental) in situ, I swap out the burner pot / shells with a serviced spare. Then refurbish the removed burner and swap back at the next service.

 

[SJB060685]

As you probably know when the oil is heated above a certain temperature it will start to crack, leaving behind a black solid carbon residue, this is down to the char content within the fuel, one delivery of oil may be different slightly to the next. IF it is as simple as the well plug needing fire cement then you cleaning out the burner would of removed the carbon that would of been creating a seal and stopping the vapour from escaping. A sudden burst of yellow flame could explain this as the shells have a carefully selected amount of holes to supply air to the right amount of fuel, excess fuel with too little air will result in a yellow flame, as you say blue is what you want and indicates complete combustion. You have to remember that these burners are designed to run constantly and will be exposed to extreme temperatures, so wear and tear is expected over the years.
The idea of an anti down draft cowl is as I'm sure you're aware to prevent any down draft created by high winds etc. Without one in the right situation you could experience problems, even complete distinguishing of the flame.

 

[Isaac]

I would go back to the posts of last October and set up the Burner again from first principles. Check that the flue restrictor plate is correctly sized and installed and that all the combustion air vents are clear and free flowing.

I'll do that, thanks. But, considering that's what I did last time, and then barely a month later, this problem turns up - do I not need to be addressing whatever it is that's causing the problem? My services used to last six months, now they're only lasting a few weeks. I'm happy to service it again, but still feel I need to know what keeps going wrong.

In your last post you indicate that there are adjustments that you cannot make. What are these?

The leveling screws on both the oil control valve and the burner are rusted solid. I can't adjust the level of either, but this has never been a problem in the last six years, so, again, I feel I'd need a very good explanation of why it's suddenly a problem now before forking out £600-700 to replace both. What I'm concerned about - I hope you'll understand - is that such replacement parts are very expensive and no-one seem to be able to give me a convincing explanation as to why either might suddenly need replacing after a service (not gradually getting worse), nor how either could actually cause my symptoms (in this case now, crackling noises and sudden ignition of excess oil.

I do check the oil levels and the oil flow rate at service (both were fine), but this is obviously not the problem. After my last service (thanks to your excellent advice about the restrictor plate), everything was fine. Things have just become not fine out of the blue. If I service it again, check the oil levels again,, what's to stop it from just going wrong again a few weeks later? I need to know what factor - outside of me servicing it - might be causing it to go wrong in this way. I I can't track down that problem, I'm just going to end up spending a fortune of replacement parts, none of which might actually be the problem.

As previously stated - rather than service the burner of an older vaporising range (which by their nature are temperamental) in situ, I swap out the burner pot / shells with a serviced spare. Then refurbish the removed burner and swap back at the next service.

Can I ask what you do to "refurbish the removed burner" that I might be missing in my servicing. Even if it means having the rayburn off for a couple of days, I could theoretically give my burner a really good 'refurbish', but I've already remove every trace of carbon back to bare metal. I'm not sure what else to do

IF it is as simple as the well plug needing fire cement then you cleaning out the burner would of removed the carbon that would of been creating a seal and stopping the vapour from escaping.

But wouldn't that have happened every time I serviced it in the previous six years? Why might it suddenly be a problem now? Also,, the problem has arrived some weeks after my last service - ie when freshly serviced it was fine (no carbon at all) then, a few weeks later, after having done nothing at all to it, I get this whooshing/crackiling problem. If it was caused by a bad plaug, surely it would have been worse immediately after the service?

You have to remember that these burners are designed to run constantly and will be exposed to extreme temperatures, so wear and tear is expected over the years.

Indeed - but these problems occurred suddenly one day after a service, six years ofcompletley trouble-ffree operation. I take everything out, clean it replace the wicks, check the levels, put everything back and then all these problems start occurring. It really doesn't sound like wear-and-tear. I really sounds like I did something wrong when I serviced it last. I just can't seem to get what that might have been.
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I understand you guys must be really busy and I greatly appreciate the time you've given so far, but if I could ask one additional favour. I've had so many suggestions, I'd just like to check my understanding, If you could correct any I've got wrong.

1. Crackling noise is cause by too high a fuel level - but given that it's just arrived out of the blue, I need to be looking for something which can raise the fuel levels despite me not having touched the burner or the the OCV.

2. Whooshing noise (with sudden big yellow flame) is the sudden ignition of unburned fuel - this is caused by vapor escaping from somewhere but because the air supply is carefully balanced it does not burn like the fuel on the wick. Again, as this problem has just turned up out of the blue, without me touching any component parts - I need to be looking for a reason why vapour might be escaping, but one which would not also apply a few days ago (when it was burning fine).

So - what changes take place inside a vapourising burner over a few weeks?

Carbon build up (but that always happens and hasn't been a problem in the last six years - plus the problem occurred immediately after service the time before this one), fuel quality changes (but no-one has suggested any way that might cause my symptoms), fuel filter gets more clogged (again, seemingly not related to my symptoms), flue gets gradually blocked (not really at a rate enough to cause problems a few weeks after it was last swept), OCV might get knocked out of level (impossible with mine due to rusted feet), inlet gets blocked (easy to check - it's not)...

Have I missed something? If the alternative is to spend nearly a grand on replacement parts I really want to be quite sure what the problem is.

Thanks

 

[Brambles]

Issac,

Vaporising burners can be quite difficult to set up to operate properly. There is very little leeway for error. They don’t last forever, over time the shells distort and occasionally the base develops cracks - so no two older burners are ever the same. When I refurbish them, I completely strip them down, clean the shells, try to remove any distortion, clean the breather holes, align the shells so that the seams are correctly positioned, fit and trim new wicks. 6 months operation for an aged unit ( no disrespect ) before a service is in my view quite good.

I fully agree with your comments on the cost of parts either sourcing or getting them made. That also applies to man hour costs when you get in “experts” to service / resolve issues. There are not that many people around who are regularly working on these type of converted units.

I would however source a second burner set ( or at least the shells) if it is your intent to keep the range going for as long as possible. Having a second burner if often quite eye opening as to what your (the) current burner should look like!

The symptoms you are currently describing are directly related to poor combustion. Resolution is a process of painstakingly working through the process from oil flow to flue pull to identify and eliminate the problem. In my experience, it is often a combination of small issues that result in problematic or erratic performance.

Apologies that I don’t have a simple quick fix - but with perseverance you will find the gremlin (s)

 

[SJB060685]

Hi.

First off I am NOT suggesting buying a replacement burner at all. These burners are simple in operation and it's just a case of checking everything thoroughly.

Question 1. Crackling can be caused by too high a oil level but if you've checked the oil depth routinely and are happy with result and the OCV and burner are solid then we can probably eliminate that.

2. Yes if the plug was the culprit then this could cause this issue but you are suggesting it was fine initially after service? The same could also be caused by a couple other reasons. 1. Blocked filters, especially the one in inlet to OCV. It could also be caused by a blocked or partially blocked metering stem. As I said way above as well if there were two appliances coming off the same filter at tank then that could potentially cause this and much worse but you said it was the only appliance correct?

Is there a pattern to this whooshing? Ie. Every 5 minutes for example. Is it happening on both high and low fire?
You say you checked flow rates. How did you check, where did you check and what were your readings? Is the appliance struggling to get up to temperature during all this?

 

[Isaac]

Apologies that I don’t have a simple quick fix - but with perseverance you will find the gremlin (s)

Not at all, you've been very helpful. I'm just sorry I don't have a nice simple problem to fix, it might have been more rewarding.

Question 1. Crackling can be caused by too high a oil level but if you've checked the oil depth routinely and are happy with result and the OCV and burner are solid then we can probably eliminate that.

So, is there another possible cause of crackling noises you know of?

It could also be caused by a blocked or partially blocked metering stem.

If that's the bit I'm thinking of, I did do the 'pressing down' thing with it, to clear any blockage. No change though,

you said it was the only appliance correct?

Yes, that's right.

Is there a pattern to this whooshing? Ie. Every 5 minutes for example

Interesting. I think there probably is, but it's less frequent that that, so hard to tell. I certainly never get like three in a row or something, they're only ever single occurrences separated by a long gap (ten minutes at least, possibly more).

Is it happening on both high and low fire?

Yes, but I think maybe a fraction less on higher flame, not sure about this though. I did check that early on, but with ten or more minutes between whooshes, it's hard to measure exactly.

You say you checked flow rates. How did you check, where did you check and what were your readings?

I let it drip into a measuring cup for a certain number of seconds. I got the instructions from an oil burner maintenance website and just followed them. I'll try to find exactly where it was.

is the appliance struggling to get up to temperature during all this?

No, not all all. Oven temperatures and water temperature are both completely normal.

 

[SJB060685]

The metering stem has a very fine groove in it which when positioned in low or high fire regulates how much fuel passes by. A single dog hair or bit of muck is enough to partially restrict or completely block the flow of oil, simply pushing down on the spring will not dislodge any accumulated muck, 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.

The fact you say there is a pattern (which is why I asked) suggests that there could very well be a fuel supply issue somewhere. If filters were partially blocked then the burner will ignite and start burning fuel but might not fill the OCV quick enough, fuel eventually comes through goes to burner and could get this whoosh. Checking level of oil in OCV while burner runs for ten minutes will rule in or out that but would not show a partially blocked metering stem.

Honestly I don't know of any other reason for the crackling, other than dirty/contaminated fuel, perhaps Brambles does?

 

[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!