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?