Welcome to the forum. Although you can post in any forum, the USA forum is here in case of local regs or laws

View the thread, titled "flue gas analysis - too much O2" which is posted in Gas Engineers Forum on UK Plumbers Forums.

Jennie

Gas Engineer
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
 
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.
 
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.
 
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.
 

Official Sponsors of Plumbers Talk

Reply to the thread, titled "flue gas analysis - too much O2" which is posted in Gas Engineers Forum on Plumbers Forums.

We recommend City Plumbing Supplies, BES, and Plumbing Superstore for all plumbing supplies.

Thread starter

Jennie

Gas Engineer
Joined

Thread Information

Title
flue gas analysis - too much O2
Prefix
N/A
Forum
Gas Engineers Forum
Start date
Last reply date
Replies
14

Thread Tags

Thread statistics

Created
Jennie,
Last reply from
Dan,
Replies
14
Views
920

Weekly or Monthly Email Digest

Back
Top