Kerosene Flue readings

happylad

Hi

I was just wondering if I could get your opinion on the attached please. They are 2no readings that were on my flue of the oil boiler I have. It's a riello 3.2 kerosene burner.

He said it was better to reduce the excess air but I see the efficiency of the boiler reduced.

Can ye help me understand the readings. Should the CO2 and excess air be lower.

Thanks in advance

jimf

depends on a lot of things really

was the boiler up to operating temp when these readings wer taken

what boiler are we talking about some boilers you can leave at 12 co2 others you cant

excess air will be what it is as a general rule 35% excess air will give a co2 of 11.5%

looking at the time difference in those printouts I would guess your second one wasn't far off operating temp

happylad

Thanks for getting back to me. Yes the boiler was up to temp. It's a warmflow 150he. It says in book it prob should be 11.5% Co2.

It doesn't say anything about excess air. Is this important also or should getting the CO2 lower be more important

jimf

maybe just me but I wouldn't leave a boiler like a warmflow at 12%co2 at this time of year

usually 11.5% co2 for me as it allows a bit for difference in air quality

jimf

happylad wrote: »

Thanks for getting
g back to me. Yes the boiler was up to temp. It's a warmflow 150he. It says in book it prob should be 11.5% Co2.

It doesn't say anything about excess air. Is this important also or should getting the CO2 lower be more important

more air will drop the co2

the boiler eff will vary through out the heating season so don't be reading in to that too much either

happylad

Thanks for getting back to me. I will leave it at that. He reduced the oil pressure to 8bar and opened to head to setting no 5. He reckoned it should help with efficiency

jimf

burners are variable so a lot of different results can be achieved

once your service eng is happy that's the main thing

happylad

Thanks for the assist.

One final question just trying to understand the report is the Co2 the most important thing that the service engineer is looking at. Does the Co2 reading take preference over the excess air.

John.G

Jimf.
Is that efficiency the net or gross value?? because the analyser I presume cannot calculate the condensing effect if any as condensing doesn't commence until the boiler return temp is ~ 50/55C and full condensing would only be achieved with a boiler return temp of < 20C which will never happen.
What is the lowest flue gas temperature you yourself has observed in a condensing oil boiler.?
What would you expect the flue gas temperature to be or is this not displayed in the report?.

jimf

happylad wrote: »

Thanks for the assist.

One final question just trying to understand the report is the Co2 the most important thing that the service engineer is looking at. Does the Co2 reading take preference over the excess air.

the excess air is not really important its only part of the whole combustion set up

as a service guy myself I look for a co2 that im happy to leave a boiler at

other things also come into like co emissions again the lower here the better most manf are happy once its under 100ppm but for me I really like to see this lower anywhere around 100ppm and im looking for a reason

jimf

John.G wrote: »

Jimf.
Is that efficiency the net or gross value?? because the analyser I presume cannot calculate the condensing effect if any as condensing doesn't commence until the boiler return temp is ~ 50/55C and full condensing would only be achieved with a boiler return temp of < 20C which will never happen.
What is the lowest flue gas temperature you yourself has observed in a condensing oil boiler.?
What would you expect the flue gas temperature to be or is this not displayed in

the report?.

this would be nett value john

the average fga temp on modern he boilers is approx. 75c john this can vary from boiler to boiler at full working temp

happylad

Jimf

Thanks for the info. I just wanted to get an understanding myself of the report. I prob should have asked him when he was here.

I'm not goin to query it but in your opinion does reducing the pump pressure from 10bar to 8bar make a burner more efficient.

John.G

jimf wrote: »

this would be nett value john

the average fga temp on modern he boilers is approx. 75c john this can vary from boiler to boiler at full working temp

Does it also just measure the net value on SE boilers?.
I know you are still gaining ~~ 7% over a SE boiler, I think the last report on my Firebird SE was ~ 230 C flue gas temp, does that sound right.?

From my industrial oil/gas fired steam boiler days I think +or- 100C resulted in +or- 4.5% efficiency with 15% excess air or somewhere around this.

jimf

John.G wrote: »

Does it also just measure the net value on SE boilers?.
I know you are still gaining ~~ 7% over a SE boiler, I think the last report on my Firebird SE was ~ 230 C flue gas temp, does that sound right.?

From my industrial oil fired steam boiler days I think +or- 100C resulted in +or- 4.5% efficiency with 15% excess air or somewhere around this.

it measures gross value on se boilers john the fga can be switched from he to se mode

230 c would be spot on for your boiler

your boiler will be running at somewhere around 84% gross eff

jimf

happylad wrote: »

Jimf

Thanks for the info. I just wanted to get an understanding myself of the report. I prob should have asked him when he was here.

I'm not goin to query it but in your opinion does reducing the pump pressure from 10bar to 8bar make a burner more efficient.

not that you would notice

maybe he thinks the boiler was oversized for your house

John.G

jimf wrote: »

it measures gross value on se boilers john the fga can be switched from he to se mode

230 c would be spot on for your boiler

your boiler will be running at somewhere around 84% gross eff

If one accepts the figures in my attachment then I think most condensing boilers rarely do so, and even though the net figure is correct it does give a "bowl of odds" to the lower gross efficiency of SE boilers, a bit academic now I suppose since all new boilers are condensing.

happylad

Jimf

Yes that would make sence. The house is just under 3000sq ft and has UFH.

He did say it was perhaps too big a boiler for the house.

I got him back initially as the boiler was misfiring (making an effort to fire the burner but the burner never lite). I assume it was still wasting fuel while doing this.

Now after he going (Prob around 3weeks since he was here) the boiler mis fires once or even twice before igniting. Doesn't happen all the time just sometimes. Would wind affect it. Flue is sticking out north wall

jimf

John.G wrote: »

If one accepts the figures in my attachment then I think most condensing boilers rarely do so, and even though the net figure is correct it does give a "bowl of odds" to the lower gross efficiency of SE boilers, a bit academic now I suppose since all new boilers are condensing.

the fga printout from any given boiler john is only the performance of the boiler at that given time

the seasonal eff is whats really important

jimf

happylad wrote: »

Jimf

Yes that would make sence. The house is just under 3000sq ft and has UFH.

He did say it was perhaps too big a boiler for the house.

I got him back initially as the boiler was misfiring (making an effort to fire the burner but the burner never lite). I assume it was still wasting fuel while doing this.

Now after he going (Prob around 3weeks since he was here) the boiler mis fires once or even twice before igniting. Doesn't happen all the time just sometimes. Would wind affect it. Flue is sticking out north wall

hard to guess as to the cause but been overaired would be a cause but from your printout your boiler is not overaired

there is a slight possibility that the photocell may be acting up and failing to see the flame but I would imagine that this would be more an everyday issue at this stage

the firing head position too could be an issue I think these come factory set from warmflow at 5

happylad

Thanks for getting back to me. I must ask him about that just to see what he says. Hes coming back this week to service my neighbours and hes calling to me anyway. Would it possibly cut down on kerosene usage to close the head down a bit more or is the head purely for combustion air to fuel ratio..Does it mean the bigger the opening on the head the more fuel it uses

jimf

happylad wrote: »

Thanks for getting back to me. I must ask him about that just to see what he says. Hes coming back this week to service my neighbours and hes calling to me anyway. Would it possibly cut down on kerosene usage to close the head down a bit more or is the head purely for combustion air to fuel ratio..Does it mean the bigger the opening on the head the more fuel it uses

the head is all to do with firing

happylad

Just a query for ye. My burner doesn't seem to be performing in the sence that it appears to be using a lot of kerosene. It has used nearly 900ltrs in a little over 2months.

The boiler was service around 4months ago but it still appears to be misfiring periodically. It will go to ignite but takes 2/3 attempts to actually fire. I had the technician back 2 or 3 times since but after 3/4 weeks it reverts back to continuously misfiring (not holding flame) but still keeps drawing keroscene. The last time he was back he adjusted combustion head to 5 and changed nozzle again to 1.00 80.S. I was tidying up the garage and found a nozzle on the floor 1.00 60s.

If I look at the burner manual it tells me the angle should be 60deg danfos type s. If I look at boiler manual it says it should be danfos 80deg h. I have attached photos.

Can anyone assist as to what might be the best course as I am at a loss as to what to do. To be fair to the technician he has said he is stumped as he says he has checked everything and can't figure it. I think the nozzle could be the issue.

Wearb

happylad wrote: »

Just a query for ye. My burner doesn't seem to be performing in the sence that it appears to be using a lot of kerosene. It has used nearly 900ltrs in a little over 2months.

The boiler was service around 4months ago but it still appears to be misfiring periodically. It will go to ignite but takes 2/3 attempts to actually fire. I had the technician back 2 or 3 times since but after 3/4 weeks it reverts back to continuously misfiring (not holding flame) but still keeps drawing keroscene. The last time he was back he adjusted combustion head to 5 and changed nozzle again to 1.00 80.S. I was tidying up the garage and found a nozzle on the floor 1.00 60s.

If I look at the burner manual it tells me the angle should be 60deg danfos type s. If I look at boiler manual it says it should be danfos 80deg h. I have attached photos.

Can anyone assist as to what might be the best course as I am at a loss as to what to do. To be fair to the technician he has said he is stumped as he says he has checked everything and can't figure it. I think the nozzle could be the issue.

Could you post the combustion test results here to see if we can see anything wrong with them?

happylad

Thanks for the reply.

Please see below. They appear ok but can't seem to explain why the boiler is misfiring. I think myself if the nozzle.

Wearb

happylad wrote: »

Thanks for the reply.

Please see below. They appear ok but can't seem to explain why the boiler is misfiring. I think myself if the nozzle.

When was that test done?
What nozzle then?
Pump pressure then?


What model and type Warmflow?

happylad

Test was done only last week. I borrowed the unit of the technician. The nozzle was the 1.00x80deg s on it. Pressure on pump is 8bar. The burner was firing 2/3times at that stage before it would ignite

Wearb

happylad wrote: »

Test was done only last week. I borrowed the unit of the technician. The nozzle was the 1.00x80deg s on it. Pressure on pump is 8bar. The burner was firing 2/3times at that stage before it would ignite

I am not familiar with this boiler, but I think that 5 on the head setting might be a mis-print and perhaps should be .5. Give warmflow a call or email on that. I have usually had a quick response from them.



I would always give precedence to the boiler manufacturers instructions over the burner makers and I would expect no trouble with that nozzle (other than any nozzle can be faulty) Perhaps try a new nozzle. I would also try lowering the co2 about .4%



Do a smoke test on it also.



Is the cell always clean?

Is the pump pressure stable and gauze and filter clean?

happylad

Thanks for coming back to me. I emailed them last week and yes they were helpful and very quick to come back. See response.

I might ask my man could I borrow the gas analyser and adjust the head to see can I bring it down. Would you think it would do no harm to try 0.5 and work away up if needs be until the correct reading is achieved. Ideally what readings should you see for co and excess air.

I'll get the technician back either way in the new year when he has a bit more time

jimf

is it only doing this when boiler is starting from cold

happylad

Yes it does this from cold but in saying that I have seen it doing it after it has been on

jimf

it may be a longshot but I would chance putting a new photocell in it just to rule this out

usually they don't fail this way but have had them do funny things when just going out of parameters

is your engineer happy that you have a good constant fuel supply to the burner