Carbon Monoxide reading 6500 and rising!!!

[gassafe]

Hi guys & gals,

So upon servicing a 6 kw gas fire, (stove type with closed doors), cleaned coals, replaced as per the book, cleaned burner etc, smoke test chimney. All went okay, the flame picture looked perfect, crisp blue flames!

I then put the analyser up the draught diverter at the rear expecting a nice low reading, but whilst on maximum the boiler Co level shot up to 6000 plus ppm before tripping out my analyser!!! I turned off the appliance as it was late in the day until i could investigate further.

Im thinking go back and gas rate the fire, checking inlet pressure at burner (book says 18mbar), re check coal posistions???

The manufacterer said coals may need replacing, or door seals, and confimed no permanent ventilation required for this model!

What else would you guys check, theres not much to adjust on a gas fire other than the restrictor elbow / inlet pressure is there? What else could cause such huge co levels from a 6kw fire which without my gas analyser i would have left in operation thinking the flame picture was good!

I am going to flue gas everything now... its scary to think a nice looking flame can be producing co levels like this! My analyser is Testo 2 years old, calibrated too.

Thanks

 

[DirksPlumbing]

My lord, you left the analyzer in for that long? Do not expect your O2 cell to still have a reasonable expectation of life. Did you run the fire for 10 minutes on full after finishing cleaning? Hope the coals have not been replaced by real ones :lipsrsealed2:?
But yes, best thing to start with is recheck the coal positions. And especially if the coals are the right ones for the specific fire.

This is one of the reasons why I do not put my hands on a fire.

 

[kozak1968]

I would check with another analyser . Or you could re check an appliance that you know has a good reading.

 

[AWheating]

the first problem is the appliances design means its not going to burn that clean anyway. What did the manufactures say any fga reading should be? did it gas rate as MI?

check gas supply, coals, door seals, air supply etc.....

 

[bright spark]

Sounds obvious, but check that it is a 'natural gas' fire, some clown could'ver fitted wrong fuel type fire. Could be wrong or partially blocked injector. Gas tray could be cracked. Check the gas rating at the meter. Could be badily overfired

 

[Billy Bob Bob]

be interesting to see what the manf says

 

[migoplumber]

unusual for a fire. would definelty gas rate before sticking me fga in the hole again.
set burner pressure next, then leave for your 10 minutes and try again. once the fga is in the hole and you start to see the co reading going up like that,
try to guage the amount its going up - if it looks like its going super high +2000 ppm pull it out ! and recheck above - flue blockages and the rest.
sometimes you have to leave in at high amounts to set it up correctly, just remember to charge customer for the new o2 cell.
tho got to say never had that on a fire !

 

[dontknowitall]

Sorry for the foot in mouth remark but have you contributed to the "When I die" thread, what with readings like that ...

I'll keep looking in on this thread as these FGA readings frequently confuse me.

 

[migoplumber]

yeah, should of added, hold your breath.
on the plus side its really nice to see somebody actually really fga a fire. it would of been really good to do the room co test, and then show the customer how you have just saved his/her hopefully her life.
you might of got a bonus ! x

 

[Billy Bob Bob]

i think there should be a thread started to help the guys and gals with fga readings edward TBH doing the fga course teaches them nowt,most think 00004 and .00004 are totally different can any of you lads put together a good guide on fga result interpretation think it would really benefit some of the peeps,i can make it a sticky then

 

[migoplumber]

good idea. i would like to have a bash. will give my thoughts on fga in arms and anybody could add, or shoot me down. move it where you wish !

 

[gassafe]

Re attended to gas rate & check inlet pressure, all okay at 6.5 kw & 18mbar inlet pressure.

manufacterers just said check door seal & coals. Door seal was okay, & the fire provided the same high readings with no coals within the fire ( this is the test it says to do before positioning the coals for the first time)

The fire on minimum provided okay reading, but on high flame the same high co2 readings.

Co2 test in the room was fine, no ppm in the room at all.

The analyser is good, its calibrated & readings are fine on other appliances.

The instructions dont mention any readings of flue gas analysis, and if done as per instuctions then the fire is working fine??

 

[Billy Bob Bob]

good idea. i would like to have a bash. will give my thoughts on fga in arms and anybody could add, or shoot me down. move it where you wish !

its over to you then shaun think it should stay in the arms most are on the gsr only anyway

 

[Billy Bob Bob]

Re attended to gas rate & check inlet pressure, all okay at 6.5 kw & 18mbar inlet pressure.

manufacterers just said check door seal & coals. Door seal was okay, & the fire provided the same high readings with no coals within the fire ( this is the test it says to do before positioning the coals for the first time)

The fire on minimum provided okay reading, but on high flame the same high co2 readings.

Co2 test in the room was fine, no ppm in the room at all.

The analyser is good, its calibrated & readings are fine on other appliances.

The instructions dont mention any readings of flue gas analysis, and if done as per instuctions then the fire is working fine??

The instructions dont mention any readings of flue gas analysis,
answered your own question there,but you need it in writing that the manf dont require one ,if all other tests check out dont you think the clues in the fact that its a gas fire?most gas fires have a modified flame picture for effect therefore your fga readings are going to be off the scale,i dont test most fires mainly because its physically impossible

 

[GrahamM]

Re attended to gas rate & check inlet pressure, all okay at 6.5 kw & 18mbar inlet pressure.

manufacterers just said check door seal & coals. Door seal was okay, & the fire provided the same high readings with no coals within the fire ( this is the test it says to do before positioning the coals for the first time)

The fire on minimum provided okay reading, but on high flame the same high co2 readings.

Co2 test in the room was fine, no ppm in the room at all.

The analyser is good, its calibrated & readings are fine on other appliances.

The instructions dont mention any readings of flue gas analysis, and if done as per instuctions then the fire is working fine??

This has been discussed in a number of posts.
Fires by design do not burn clean. This is not a good clean flame from a boilers burner we are talking about. It is a visual set up that burns badly to look good, by design and therefore gives high FGA readings.
That is why the manufacturer has no figures.
If flue flow, spillage, gas rate/BP good, burner and coals clean that is all that is required.
I work on fires near enough every day and unless it is fluless the FGA stays in van.

 

[migoplumber]

bummer, wrote it and got logged out at posting. you shall have to wait till morning. was such a good read