Oil fired Rayburn persistent fumes after service.

[Isaac]

Do you you think there is any possibility that you have inadvertently disturbed the flue closure plate?

Yes, It's not impossible, however...

The problem has inexplicably been fixed. After my last take-everything-out-and-put-it-back-again the smell persisted for about half a day, i turned the dial up a fraction (just to get our hot water back) and the smell went away, 24hrs later it's still gone. I should say, in the previous couple of weeks wrestling with this problem I have tried all sorts of settings so it's not just a matter of higher flame=no smell, it must additionally be something I did last time.

Anyway, I haven't dared try it on any other settings yet (I just want a break from fixing it for a while), but there's one matter I'd like to ask your opinion on, if it's OK. All this recent fixing issue has made me hyper-attentive to flame colour and now I'm not trusting my memory of what it's normally like. I've had 100% blue, but sometimes I look and there's a trace of yellow/orange, just at the tip of the otherwise blue flames. I'll try to get a photo, but it looks just like this image from the guidance I've been using.

not literally 100% blue. Is that something I need to get checked out, or is that part of what you'd still call 'blue flame'?

 

[Brambles]

Issac,

The flame should be completely blue. The yellow flicker is sign of incomplete combustion - which could just be dirt in the burner.

I would source a second burner set and next time you service the range swop out the burners and give the existing ones a thorough clean and check for cracks and / or porosity in the cast iron.

Having said all the above - the yellow flicker you have at the moment is not a major issue - but it will increase the volume of carbon deposit / sooting.

It may settle down after a few days.

Good luck

 

[Isaac]

Issac,

The flame should be completely blue. The yellow flicker is sign of incomplete combustion - which could just be dirt in the burner.

I would source a second burner set and next time you service the range swop out the burners and give the existing ones a thorough clean and check for cracks and / or porosity in the cast iron.

Having said all the above - the yellow flicker you have at the moment is not a major issue - but it will increase the volume of carbon deposit / sooting.

It may settle down after a few days.

Good luck

Thanks.

Unfortunately the smell has just come back again. I haven't done anything except open the top door (I was thinking of getting a photo of the flames), literally haven't touched anything - how's that even possible?

The only thing I can think of was that it was really windy the 24hrs over which there was no smell. So maybe all that was happening was the smell was being drawn up the flue better (as I think you've mentioned should happen). I suppose that might indicate something wrong with the flue (so I've booked to have it swept anyway - just in case), but I think it unlikely because I can't see how it would suddenly become a problem overnight. If you remember, this problem was non-existent the day before the service and the arrived the day after. Can a flue block up that quickly?

One weird thing I'd like to ask an expert. In our flue box, the exit from the Rayburn itself is blocked by two sheets of metal with a 1-2cm slot cut in one of them - meaning the entire exit hole is narrowed to about 1x5cm. It's always been like this and I presumed it was something to do with the conversion to oil (the Royale is a solid fuel range really). The reason I ask is that if 1x5cm is the correct exit hole, then it's very hard to see how any flue blockage could possibly result in a draw less than that (the flue is about 10cm diameter), but if it's not normal, then I suppose all sorts of things might have gone wrong with it? Why might the flue exit need to be narrowed in the first place?

 

[Brambles]

Issac,

Starting with the restrictor plate in the flue. This is normally a plate that slides across the bottom of the flue inlet to optimise the “pull” from the flue on the boiler. The pull on the flue ( if you can measure it ) for a vaporising burner should be less than -1 mm H2O but not more than -1.5mm H2O. The plate you describe has probably been custom made to give those conditions rather than adjusting the restrictor plate. That is not unusual - it is a one time setting normally.

I assume that when you had the “engineers” out they measured the boiler draught? You cannot do that yourself - unless you have the equipment!
What you can do is:

For the flue, check for spillage using a match test all around the spigot, joints and restrictor (if fitted).

Check all the door seals on the range - thay must all be tight fitting and not pass air in either direction.

Check that the room ventilation providing the combustion air is properly sized for the boiler. The boiler should run properly with all doors and windows closed any extract fans switched off, so that all combustion air is only coming through the permanent vents.

Also may be worth rechecking that the burner shells are all undamaged and seated properly - they should be a tight fit into the burner to be as airtight as possible.

Apologies, I have no real immediate advice - I think that you now just need to work through the complete basic set up of the range to ensure that it is all correctly configured. I appreciate that you probably do not need it, but the starting point is always a flue clean

 

[Isaac]

Starting with the restrictor plate in the flue. This is normally a plate that slides across the bottom of the flue inlet to optimise the “pull” from the flue on the boiler. The pull on the flue ( if you can measure it ) for a vaporising burner should be less than -1 mm H2O but not more than -1.5mm H2O. The plate you describe has probably been custom made to give those conditions rather than adjusting the restrictor plate. That is not unusual - it is a one time setting normally.

Thanks. I've had that plate out, cleaned it and put it back several times during services as I always check the flue box as part of my service. I've never been particularly accurate in how I put it back (not to the mm type accuracy) so it's in basically the same place it's always been. One less potential cause I think.

I assume that when you had the “engineers” out they measured the boiler draught? You cannot do that yourself - unless you have the equipment!

I wasn't in the room with them all the time, but I don't think they did anything like that. They didn't mention it anyway. They just took the burner out, scraped it a bit, put fresh wicks in (I think), vacuumed around the chamber and fluebox and that was that. As far as I know. I clearly need to get myself some more technical engineers.

For the flue, check for spillage using a match test all around the spigot, joints and restrictor (if fitted).

Done. Match was steady all around, good draw in through the air inlet. There's no sign of any actual draught, even from the hob and chamber door where the smell is coming from.

Check all the door seals on the range - thay must all be tight fitting and not pass air in either direction.

The hob seal is new(ish), the burner chamber door doesn't have a seal and never has had. There's not even a place for one to go as far as I can tell.

Also may be worth rechecking that the burner shells are all undamaged and seated properly - they should be a tight fit into the burner to be as airtight as possible.

Done. Measured them with a flat-plate. They're completely flat at the base. The engineer mentioned possibly using exhaust sealant paste if the problem continued, but I'm reluctant to do that as it's obviously never needed it in the past.

Apologies, I have no real immediate advice - I think that you now just need to work through the complete basic set up of the range to ensure that it is all correctly configured. I appreciate that you probably do not need it, but the starting point is always a flue clean

Not at all, you've been really helpful, I greatly appreciate it. The flue clean is booked in (over a month off though, our sweep is very popular at this time of year), so I'll just have to wait for that and go from there.

Thanks again for your help.

 

[Brambles]

Thanks,

Very helpful responses.

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.

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.

 

[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