Really badly choked up boiler

[Millsy 82]

I went to an 18 month old Grant vortex combi 26 which was the worst i've ever seen to the point that the baffles had an inch of soot on top of them and when I pulled the swirl baffles out they were solid with soot. I cleaned it all out so it was sparkly clean changed nozzle etc etc

I was expecting he oil pump to be too high pressure but it was at 8 bar and the air setting was about 5.5 which I wouldnt of thought would be too far out. but it was smoking a treat so opened the air up until it was fairly clean then put my analyser in and I cant get the co2 below 12% with the oil pressure on 8 and I had to wind the air as far as I could.

In the end I dropped the oil presssure to 6.5 bar and I managed to get the co2 down to 11.4%. What I cant work out is why with the air fully open will it not drop below 12% is it because

A Its still burning off some muck around the heat exchanger. (this is my thought)

B They are not using Kerosene? and maybe using gas oil or even red diesel or something else?

Im going back early next week to check it again as it was so hoping it burns off all the muck and I can just reset it all back up and away it goes>

 

[Killy Bing]

Hmm... What colour was the oil?

red diesel is gas oil btw
Did you change the nozzle?

also if its new, did you check the burner had the correct blast tube?

 

[Bunker]

Should have dropped a smaller nozzle in for a week to help burn it off. I wouldn't want to stick my meter in that for a week. Have you checked the analyser filter?

 

[lame plumber]

wrong nozzle been fitted, or flue seal gone causing pocs to recirc, for 2 ideas

 

[Millsy 82]

Yeah gave it a full service so new nozzle hose etc.

I didnt realise gas oil and red diesel were the same lol. It looked like kereosene to me

 

[Bunker]

Did you check it was the right nozzle in the box? Flue is probably choked too, chuck a soot breaker in :/)

 

[Millsy 82]

wrong nozzle been fitted, or flue seal gone causing pocs to recirc, for 2 ideas

Checked the nozzle before I put it in to make sure it was what was written on the tub. Right nozzle for the boiler as I double checked the manual. I ran the boiler with the air hose disconnected as well no difference as I thought it may be something like that.

 

[Killy Bing]

Yeah gave it a full service so new nozzle hose etc.

I didnt realise gas oil and red diesel were the same lol. It looked like kereosene to me

Did you replace the nozzle like for like or as per MI's?
i always get them up on my phone as i would say about a tenth of what i go too have the wrong nozzle!!

yup!

 

[Millsy 82]

Should have dropped a smaller nozzle in for a week to help burn it off. I wouldn't want to stick my meter in that for a week. Have you checked the analyser filter?

Analyser filter was clean I made sure it wasnt smoking before I put it in and the inside of the boiler was spotless by the time I finished on it. (Me on the other hand was covered from head to foot in soot!)

Do you reckon it could just be burning of the muck still then? Ive worked on loads of oil boilers over the last couple of years some badly choked up but none this bad and never came accross this problem.

 

[Roger Welton]

Smells very different also. Were the FGA readings any better with the snorkel removed?

 

[Bunker]

What was the co?

 

[Millsy 82]

Smells very different also. Were the FGA readings any better with the snorkel removed?

.1% difference so nothing I wouldnt expect as the snorkel will restrict the amount of air going to it.

 

[Millsy 82]

CO was fine cant remember what it was and all paperwork is in the van down the road. I will get the readout out in the morning.

 

[Bunker]

If the CO was good, you must have done a beautiful clean then, should have been a surgeon.

 

[Millsy 82]

If the CO was good, you must have done a beautiful clean then, should have been a surgeon.

I couldnt be a surgeon I dont mind my own blood but others and I feel sick lol.

It was between 50 and 60 if I can remember right but I did leave it running for half hour before doing it. And I spent ages cleaning it as I always do so I hope it was a beautiful clean.

 

[Bunker]

Did you check the air box?

 

[Best]

Keep the oil pressure at 8 bar, disconnect the snorkel if any doubt about it or flue, check the air damper inside the burner is actually opening when you turn the Allen bolt - many can be broken on RDBs. Be sure to tighten new nozzle up fully. (easy to forget)
Unlikely, but you can have a faulty new nozzle putting loads oil out.
Co2 will be fairly decent if you removed 99% of soot. Smoke pump will show yellow reading when setting good, until all soot is gone after a day or 2.
Maybe not in your boiler, but look out for a mouse nest inside snorkel or a dead mouse inside burner or other debris - only takes a minuscule bit of fluff in the narrowest, smallest points of the burners air intake to blast tube to reduce air by large amount.

 

[Killy Bing]

As said check you have the right blast tube, the vortex can change how it burns.

 

[SimonG]

Badly sooted i normally drop out a baffle or some of the spirals or springs in the condensing heat exchanger and set it lean. Then back after a week and sort it properly.

 

[Best]

I also would put the air up a little to keep it on the safe side & let it clean itself out for a few days.
I still use a smoke pump just to reasure myself that it's not still running black.

 

[albatross]

I think you may have sorted it, just needs time to settle. It would struggle to light on diesel if at all.

 

[Killy Bing]

I think you may have sorted it, just needs time to settle. It would struggle to light on diesel if at all.

You would be amazed.
goes like slurey in the conny trap and secondery

 

[bright spark]

I presume it has 1 of those Riello RDB burner on it. This is gonna sound mad but on some models you know where you adjust the air, that's not the only air adjustment. If you take the burner out, there's a couple of screws holding the plastic casing on around the air louvre side with the air intake on the right hand side. If you remove the plastic cover to see the fan impeller there's actually another adjustment louvre. I only know this cos I got caught out with that before. So check that out, some Riello Burners have this. Check it out, it's worth a shot

 

[Best]

I presume it has 1 of those Riello RDB burner on it. This is gonna sound mad but on some models you know where you adjust the air, that's not the only air adjustment. If you take the burner out, there's a couple of screws holding the plastic casing on around the air louvre side with the air intake on the right hand side. If you remove the plastic cover to see the fan impeller there's actually another adjustment louvre. I only know this cos I got caught out with that before. So check that out, some Riello Burners have this. Check it out, it's worth a shot

Was thinking same, - the inner is a air adjustment which should be set, in theory, for the burners actual output.
The outer is for fine adjustment - normally all that needs adjusted hopefully.

 

[Killy Bing]

I presume it has 1 of those Riello RDB burner on it. This is gonna sound mad but on some models you know where you adjust the air, that's not the only air adjustment. If you take the burner out, there's a couple of screws holding the plastic casing on around the air louvre side with the air intake on the right hand side. If you remove the plastic cover to see the fan impeller there's actually another adjustment louvre. I only know this cos I got caught out with that before. So check that out, some Riello Burners have this. Check it out, it's worth a shot

Do you mean the louved disk you set round to your outputs?

 

[bright spark]

The 1 inside the air box under the 'snorkel'. If ye don't set that right, the outer air adjustment won't be able to greater change the CO2 levels. Maybe it was overlooked. Just thought I'd mention it incase it was missed

 

[Millsy 82]

Been Back out to it today to reset it. I whipped the baffles out again just to make sure they were not sooted up again. put FGA in it was running on 8.5% so set it all back running brilliantly now so was just the excess soot being burnt off causing the problem.

 

[WHPES]

I remember a mate of mine played a practical joke on his apprentice whereby he got the apprentice to go through the boiler servicing but tipped a bit of oil inside the combustion chamber when the apprentice went to the loo, and predictably enough the apprentice was unable to set up the boiler combustion for 20 minutes until the oil burnt off, with my mate saying "you must have done something wrong", then going off to snigger to himself.

On another occasion the guy was fitting a WC and the other lads on site kept tipping a little water behind the pan and telling him that the WC was leaking and he would need to take it off and refit it. This went on about 4 times before he realised someone was taking the P.