riello 40 black smoke

[brianc1]

hey lads,

have noticed a couple of riello 40s that i have serviced and set up with fga starting to produce some black smoke after a few weeks. they are both old and when i went back and inreased the air intake a little bit they worked fine. im presuming the burners are just on their last legs and parts are starting to wear. any other suggestions?

 

[dontknowitall]

Could be wrong oil pressure or air settings incorrect, or failing oil pump, or blocked up flue.

 

[SimonG]

What CO2 did you set them at originally?

 

[brianc1]

oil pressure and air was correct and had tweaked it with a flue gas analyzer. anyway if they were wrong i would be getting incomplete combustion and therefore black smoke straight away as opposed to a few months later. im not sure if a blocked would create black smoke????? or just cause lockout. co2 usually around 12%. i set them up keeping the co below 80ppm and excess air around 25% and usually the cos is around 12% then automatically.

 

[dontknowitall]

Not enough ventilation for the boiler?

 

[Best]

Maybe set too fine. Use an ordinary smoke pump first, & set air setting. Set smoke number to zero on smoke scale. Don't listen to anyone saying the smoke number is ok if higher than zero for that burner. The co2 should be 10.5% or more on Riello 40 but don't expect it to be above 11% always. If boiler has a low level flue or a short standard flue, then keep the air setting a tad higher, as you risk boiler going sooty later. You could always have had nozzle problems, & as has been said, check ventilation.

 

[brianc1]

think its the same ventilation thats been there for years and anyway when i went back and opened shed it was still puffing out black smoke until i adjusted it. plenty of air getting into shed through eves. it may be pump pressure regulator failure so more oil is being burnt than i had set it for. not sure the mechanical workings of the pressure regulator in an oil pump. anyone know?

 

[Barry98]

is your fga due for calibration ? just a thought maybe ?

 

[brianc1]

thanks best. to be honest i got a smoke pump the same time as my analyzer but never use it. i find that once i keep the co below 80 and have 25% excess air to allow for inconsistencies with oil the smoke number would be as low as possible. i adjut air until co stars to rise then tweak it back a bit so its always a good as i can get it. and as i said the co2 nearly always works out around 12%.nozzle is new and identical to what i took out. why would boiler risk getting sooty later because of a short/low level flue? tanx

 

[brianc1]

bod,, its not due yet but anyway that wouldnt explain why it was burning cleanly and then after a few months starting burning black. im still thinking pump failure. it's either air intake decreased or oil flow increased(simulating lack of air).