Help setting up old oil boiler

[Mjt1980]

Right guys and update i have fitted another nozzle today 0.65\80 s turned the pressure down to 100psi the ppm reading have dropped but there still high around 600ppm the co2 was around 7.8% i have cleaned the boiler baffle ect but still can't get the ppm down to where i would like. Do yo think its worth running the boiler for a couple of hours and retaking a sample?

Martin

 

[WHPES]

Have you checked the flue for obstructions?

Has any oil dribbled into the combustion chamber, or has any soot got into it?

 

[Mjt1980]

Yes the flue is fine no problems there

 

[WHPES]

Is it a balanced flue model? If so, the seals between the air inlet and discharge may have broken down allowing combustion gasses into the air intake.

If not, try changing the position of the flame spreader in relation to the nozzle.

Your problem will probably be something to do with air

Also check fuel is not leaking from behind the nozzle. Sometimes the nozzle holder can be worn with repeated taking nozzles in and out, A couple of turns of PTFE round the nozzle thread will fix this.

 

[Mjt1980]

it's a conventional flue system I will try to move the flame spreader and see if that makes a difference.

 

[WHPES]

PS, high CO readings are either:

1) inadequate air supply (incomplete combustion due to insufficient oxygen)
2) Too much air supply (effectively "blowing out" the flame)
3) feedback of combustion gases into the air supply (Trianco Eurostar balanced flue boilers are prone to this as the seals in the flue can break down over time and need resealing)
4) Combustible material in the combustion chamber (such as soot either from a problem or after a flue has been swept) or oil which has dribbled into the chamber due to a fault on burner shut off, or a leak from behind the nozzle. This is why you should wait for several hours before final set-up of a boiler where the flue has just been swept, or a brand new boiler which may have oil from the manufacturing process still inside it, else you get spurious results.
5) fuel contaminated with heavier fuels or mineral oils
6) poor flame pattern from incorrect positions of flame spreader, blast tube and nozzle holder (or in the case of unmaintained boiler, build up of soot on the flame spreader, or worn out nozzle)

 

[WHPES]

Try the following:

Nozzle tip to flame spreader - 5mm

Flame spreader to edge of blast tube - 25mm

Just a hunch but worth a go

You want to be aiming at about 5 to 40ppm CO with 11 to 12 % CO2.

Another good idea is to keep hold of burners from boilers you have decommissioned. If you really can't find the problem, just whack another suitable burner on.

 

[Mjt1980]

Ok that's great that's a good tip I will start to keep back a few good burners.

 

[WHPES]

I have several used burners of different types, all in running order, so if I get a callout on a Sunday evening etc I can often just swap for another one the same which I know is in working order. I can tinker around with the bad one in the workshop at my own convenience later on.

 

[WHPES]

You're probably just going to have to play around with the spreader position until you get it right. A small amount of adjustment can have a massive effect.