ratio of 0.009ppm on a new boiler

[moogwai]

Hi Guys, just a quick one.... i was comissioning a new boiler the other day (ideal logic combi 30) i put my fga on it and ran at full rate and was getting a ratio of 0.009!! co2 reading was 9.32% and gas rate/working pressures were fine. Looked at mi's and they stated that 0.004 was the target. Now this being a brand new boier should i need to be fiddleing around with it?
I went on a wb cdi course earlier in the year and the fella said that when doing a fga check he would always go by the co2 reading as this is the gas emissions and as long as this is below 11% there would be no need to take any further action. What's your take on this?

 

[Reg Man]

Really pleased to hear that. CO 85ppm CO2 9.3%, CO:CO2 0.009. Satisfactory.

 

[Dannypipe]

i now feel like a right forrest gump!

Don't worry mate. You were being cautious and doing the right thing. Everyone can misread something.

 

[shorticus]

ok...just been back to check it once more,turns out i did miss a zero so it now reads 0.0009 phoned ideal and they said its fine as the action level is 0.004....i think we get confused about the number of zero's we need to be reading when doing a fga! i now feel like a right forrest gump!

easily done mate, no-one's perfect.
I think my analyser taps out at 200ppm CO so i couldn't reach those figures without it throwing a wobbly, i don't know if they're all the same though

 

[Reg Man]

Most low range analysers saturatate at 2,000 to 4,000 ppm CO. If you have a band A boiler with zero governor an acceptable reading would normaly be 0.0002. At 10% CO2 and 200ppm CO your ratio would be 0.0002.

 

[shorticus]

Most low range analysers saturatate at 2,000 to 4,000 ppm CO. If you have a band A boiler with zero governor an acceptable reading would normaly be 0.0002. At 10% CO2 and 200ppm CO your ratio would be 0.0002.

to be honest i didn't notice the CO2 at the time, was probably way up, i just saw the CO hit 200 then computer said no!

surely you meant 0.002 Reg Man? tricky them pesky noughts looks like we're all at it now )

 

[kevin@gesuk]

Ratio calculations

ppm in CO divided by CO2 in percent multiplied by 10000


eg

85ppm
9.3% X 10000 = 0.0009

For CO2 calculation from oxygen

CO2 maximum for nat gas is 11.9%

CO2 =

CO2max (20.9 - O2 reading)
20.9

eg

CO2 =

11.9 x (20.9 -4) =
20.9

201.11 = 9.62% CO2
20.9

 

[GrahamM]

You sure you haven't missed out a zero there and your ratio was 0.0009?

Not that often I get something right here.
Glad you got it sorted out. Easy done!

 

[archiedale]

Thanks kev, good lesson, well done

 

[Reg Man]

to be honest i didn't notice the CO2 at the time, was probably way up, i just saw the CO hit 200 then computer said no!

surely you meant 0.002 Reg Man? tricky them pesky noughts looks like we're all at it now )

Yer your quite right all these 0000000's easy done.

 

[shorticus]

Yer your quite right all these 0000000's easy done.

i'm now not at all sure that my meter said 200 maybe it was 2000, think i should've gone to specsavers )

 

[metaldust9]

yep all the 0.0000 can easily get mixed up

trigger value on my sheet for combi,s is 0.008 altho mi,s might say diffrent so 0.0009 would be well in

 

[julesverne]

those bloody noughts. I still keep looking at my sheet just to be on the safe side as i always keep questioning myself whether it's 1, 2, or 3 bloody zero's.

 

[Reg Man]

yep all the 0.0000 can easily get mixed up

trigger value on my sheet for combi,s is 0.008 altho mi,s might say diffrent so 0.0009 would be well in

Yer you are right for many boilers, but Mi's over rule guidance in CPA1. Most band A boilers (zero governed) require 0.002 ratio.

 

[derrybongo]

just as an easy trigger to remember the cut off point on the analyser ratio tests

JAMES BOND 007

When i see the ratio near this i consult the MIs

works for me but im a bit of a saddo

 

[metaldust9]

i was told 0.004 or below ok 0.004 to 0.008 needs servicing, above 0.008 I,D switch off and find out why