co/co2 co ppm readings

[x51990]

hi wondered if an experienced gas engineer could clarify something for me as i seem to be confusing myself a little...

Boiler in question is an 8 year old worcester 25 si. carried out a service, flue gas analysis test was fine, readings were as follows: (co2 % 10.1) (ppm 165) (co/co2 0.0016) so all fine, i then removed the little cap which is on the oxygen side of the flue and put the test probe in there. my readings were as follows: (02 % 20.9) (CO2 % 0.0) (co ppm 26) (co/co2 0.0520)


this is what has confused me a little bit firstly what should the co ppm on the oxygen side be? is 26 to high? secondly is the co/co2 ratio at 0.0520 incorrect? i know it should be no more than 0.004 when carrying out the combustion test but on the oxygen side i am a bit confused. could someone clear this up for me please as i am returning to the boiler tomorrow? thanks

 

[GasMark1]

when you say the oxygen side , do you mean the intake on the flue? if so as far as i am aware you don't need to test this unless they've change it without telling everyone! you only need to test combustion
Mark

 

[lame plumber]

either you hadnt let the fga zero down before re analysizing the intake flue, or you have damaged seals on the flue, there should be no co2/co in the intake gases.

regards testing the intake flue, my gsr inspector likes to see you doing so as it proves the flue seals are ok and just another safeguard. Ive picked up a couple of rotten flues doing this!

 

[GasMark1]

why are you checking the intake????

 

[dancinplumba]

hi wondered if an experienced gas engineer could clarify something for me as i seem to be confusing myself a little...

Boiler in question is an 8 year old worcester 25 si. carried out a service, flue gas analysis test was fine, readings were as follows: (co2 % 10.1) (ppm 165) (co/co2 0.0016) so all fine, i then removed the little cap which is on the oxygen side of the flue and put the test probe in there. my readings were as follows: (02 % 20.9) (CO2 % 0.0) (co ppm 26) (co/co2 0.0520)


this is what has confused me a little bit firstly what should the co ppm on the oxygen side be? is 26 to high? secondly is the co/co2 ratio at 0.0520 incorrect? i know it should be no more than 0.004 when carrying out the combustion test but on the oxygen side i am a bit confused. could someone clear this up for me please as i am returning to the boiler tomorrow? thanks

hi are you Gas Safe installer ? if so please pm gas man or redsaw your details then you will gain access to the gsr forum. thanks

 

[x51990]

hi sorry yes the air intake i am a final year apprentice,i borrowed a fga and was basically practising on my own boiler at home as i have my exams this year, i have given the fga back now but i was told by the engineer i normally work with to check this side to make sure you get the 20.9% oxygen reading which i did get, it could of been like someone else posted that i had not let the fga zero, but if i did and these were the readings then i wanted to query what the co/co2 ratio should be on the air intake as i know it should be no more than 0.004 on the combustion side, and also thought the co ppm should be 0. thanks

 

[migoplumber]

not gsr proved. do not reply

 

[REDSAW]

your not a registered gas safe technician then or qualified to use the fga?.

ask the guy you got the fga from.