Discuss riello 40 black smoke in the Plumbing Jobs | The Job-board area at PlumbersForums.net

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Thanks to all of you, I have found this thread very inlightening and has brought up a lot of questions for me

I always use a smoke tester as I am scared of wrecking my analyser if its a smoky pig, if I get smoke to 0 by gradually increasing the air and taking a smoke 3 - 4 times, I am sure its not too weak (still a 0 smoke). I finish with the analyser and more often than not a slight tweak get it to 11-11.5 CO2

with reference to winter/summer settings, it to me all depends on where the boiler draws its air, if its in a small boiler house sitting outside or using a balanced flue I am wary of outside temperatures if its very very cold, but if its in the front corner of a warm garage then I feel the weather has little effect. Engines run weak in the cold weather and rich in the summer, its all to do with the density of air etc etc but as Best says these boilers are not too sophisicated and it would have to be extreme weather conditions

I am very preoccupied by 2 readings,
1. smoke to 0 having brought it down from 1 or 2 ish so as not to be too weak
2. CO2 to be ideally 11.5

if these two readings are present I am happy

but having read this thread others seem to be interested in CO and excess air

what are the holy grail of settings if all was perfect

smoke 0
excess air ?
co ?
co2 11.5
o2 ?

which is the most important ? as in reality the only two variables present are fuel and air, so not all of the FGA readings could be individually modified without effecting another

many thanks
 
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Soot is incomplete combustion

1, not enough air for combustion (not enough ventilation to room / flue needs sweeping etc)
2, too much air (you get the effect of the air partly blowing out the flame)
3, blast tube, diffuser, nozzle distances not set right
4, too high oil pressure (too much going out not getting chance to burn)
5, too low oil pressure (not atomising properly)
6, fuel contaminated with heavier oil
7, air leak into fuel pipe causing uneven flame (usually shows as unsteady pump pressure - wheel head fusible fire valves are the usual culprit / worn out pump)
8, poor spray pattern - worn or incorrect nozzle
9, baffles not correctly positioned
 
what are the holy grail of settings if all was perfect

smoke 0
excess air ?
co ?
co2 11.5
o2 ?

Smoke 0
Excess air - must confess I don't fully understand this one! Any help please? (Is it O2?)
CO - 20ppm or less
CO2 - according to MI - usually 11.0/11.5/12.0
O2 - 5.5-6.0%
 
Smoke 0
Excess air - must confess I don't fully understand this one! Any help please? (Is it O2?)

O2 - Oxygen - constitutes only approx 21% or 1 part in 5 of the total air you breathe, and which is all around us, and the rest, apart from trace gasses, is nitrogen, which may be considered as inert. So if we have an excess air quantity of say 15 %, that is effectively only about 3% excess oxygen - which is the stuff that allows combustion.
The rest of the excess air is the aforesaid nitrogen, which contributes NOTHING to combustion, but does carry away heat in the flue, and thus reduce overall thermal efficiency. However, we can do nothing about that, as air is air. So by choosing a figure for excess air depending on fuel being burned, we can ensure that just sufficient surplus O2 is provided to ensure complete combustion, while minimising the heat wasted and carried away in the nitrogen constituent of the excess combustion air being supplied.

Look here for the full 9 yards: Combustion Efficiency and Excess Air

Hope that helps
 
ar22 and dontknow it all, there is obviously some very intelligent lads on this forum and a lot can be learned. i done an oil servicing course about 5 years ago and have been casually servicing boilers since. my instructor seemed to be very experienced and he drummed the importance of excess air into us.
because of this the first thing i look for on my analyzer is excess air, i never have it below 25% as he recommended. on some older burners it may be higher than this as sometimes as you lower the excess air co raises significantly. so i suppose actually in my opinion co is the most important, my instructor told me for oil burners the co should be kept below 80ppm (im sure there is different opinions on this) i try to keep co as low as possible followed by keeping excess air at 25% but sometimes this is impossible and excess air may be higher. generally when if i can set them up with 25% excess air and co below 80ppm, the co is around 12% and o2 around 4%.
 
ar22 and dontknow it all, there is obviously some very intelligent lads on this forum and a lot can be learned. i done an oil servicing course about 5 years ago and have been casually servicing boilers since. my instructor seemed to be very experienced and he drummed the importance of excess air into us.
because of this the first thing i look for on my analyzer is excess air, i never have it below 25% as he recommended. on some older burners it may be higher than this as sometimes as you lower the excess air co raises significantly. so i suppose actually in my opinion co is the most important, my instructor told me for oil burners the co should be kept below 80ppm (im sure there is different opinions on this) i try to keep co as low as possible followed by keeping excess air at 25% but sometimes this is impossible and excess air may be higher. generally when if i can set them up with 25% excess air and co below 80ppm, the co is around 12% and o2 around 4%.

Your dead right, a lot on here know their stuff and are willing to help which is great

Setting the boiler is all a juggling act and with only a few variables its hard to influence certain aspects without effecting something else

I have learned from reading this and to be honest I had no idea what excess air was !!

I aim for the CO2 figure as its the indication for efficient combustion and am happy if everything else comes in sensible around the figures "dontknowitall" has quoted

many thanks
 
I'm much the same. If I get the MI's CO2, O2 at 5.5-6.0% and under 50ppm for CO I'm out of there.
 
sorry dontknowitall not sure what you mean when you say 'mi'. the reason i set the excess air at 25% is to allow for fluctuations in oil/air quality. too much excess can make the whole thing inefficient. i would imagine 5.5-6% o2 has plenty of excess air as usually 25%excess air only gives me 4% o2. would you know roughly what excess air u set it with?
 
Manufacturer's Instructions - sorry, thought everyone knew that one.
 
I would recommend checking flue for blockages not enough draught. If the problem persists you may get back draught explosion. Clean chimney.
 
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