Flue integrity test

[Scott_D]

I always do a flue integrity check on the air inlet sample point. Never had an issue.
Doing one today and I realised I don’t know what values the are to be classed as a fail.

Can’t seem to find it in my books either.
Is there a TB I can read to refresh my brain?

 

[EvilDrPorkChop]

I believe anything below O2 20.6% is a fail, someone correct me if i'm wrong though.

 

[Scott_D]

Is there a CO ppm figure?

 

[cmarkr]

I think its like porkchop said below 20.6% or if its more than 0.2% co2 ratio its fail. Don't think theirs guidelines on CO strangely.

 

[Jones82]

Its air intake so the the same as fresh air, anything above normal co levels would indicate a leak from the flue seals into the air intake. This would also result in higher than normal flue readings

Edit quick google search brings up 0-9ppm for normal indoor co levels