Search the forum,

Discuss flue gas analysis - too much O2 in the Plumbing Jobs | The Job-board area at PlumbersForums.net

Status
Not open for further replies.

Jennie

Gas Engineer
Messages
283
Hi all,
Could I check I correctly understand fga readings taken off an old Microgenus combi.
The ratio is great (0.0003%). CO2 is only 3.4% (should be 7.62), O2 is 15% (should be closer to 7%, according to the boiler manual). CO was 33ppm.
The ratio passes the gas safe requirements.
However, the readings suggest the boiler is under-gassed. Solution: check incoming gas pressure to the boiler, and also the burner pressure (which I don't have - but let's assume it's low).
Would a low burner pressure would be cause for the boiler to fail the certificate?
Apparently, the gas rate was spot on. But surely it can't be - if the boiler isn't burning enough gas to use up all the oxygen.
Also, how much work would you do on a boiler if the landlord only wants the gas safety certificate? Ie, they don't want to spend money on having it cleaned, adjusted, etc, despite the engineer's better judgement. Or if a 5-yr burner seal is due renewal, but no visual damage? Obviously, if it fails the certificate, the work must be done (or the boiler condemned).
Thanks for your advice,
Jennie
 
Have you had your fga on LPG? Wouldn't be the first time I've done it!
 
Your readings are not quite correct. Is your analyser working and if so, did you pre purge it in fresh air?
 
Oh ... yeah, I did have it on LPG. I realised once I got home. How much does this change the readings?
The gas rate was good, the flame picture great.
 
Thought O2 should be 20.9 % not 7 % or am I reading things wrong
 
If inlet is within parameters, gas rating is good, seals intact, integrity 20.9% flame picture good then all should be well to pass. Just need to double check the FGA is set up for correct fuel n go back to get an accurate ratio to record on the CP12.
 
26(9) Minimum gas safety checks. Burner pressure/Gas rate where appropriate both.
 
lol delete post not getting into trouble fir posting in wrong place sorry
 
Last edited by a moderator:
if this is a public forum, have the rules changed, all this should be in a private gsr forum surely
 
It should be done with an analyser that has a calibration certificate and also a trained engineer with CPA qualifications , but your readings are well within the regulation standards, youve also an excess air reading,
 
if this is a public forum, have the rules changed, all this should be in a private gsr forum surely
I've moved it.

Report any posts that need moving we'll sort it out quickly.
 
Status
Not open for further replies.

Reply to flue gas analysis - too much O2 in the Plumbing Jobs | The Job-board area at PlumbersForums.net

Creating content since 2001. Untold Media.

OFFICIAL SPONSORS

OFFICIAL SPONSORS

Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock