carbon monxoxide concentration in boiler flue?

Any heating engineers on here?

If so, please can you remind me what is the optimum/target concentration for CO in a domestic combi-boiler flue?

I have it in my head that it should be <400ppm and ideally closer to 100ppm but it's been a while since I had to think about this

TIA

Originally Posted by Jabba

Any heating engineers on here?

If so, please can you remind me what is the optimum/target concentration for CO in a domestic combi-boiler flue?

I have it in my head that it should be <400ppm and ideally closer to 100ppm but it's been a while since I had to think about this

TIA

not used a flue gas analyser in ages, iirc reading had to be 0.0040 or less

[embee]

Funnily enough I was looking through an installation doc for a boiler yesterday. This is a Viessman but I'd guess it's pretty typical for gas combustion.

At 400ppm the boiler should be stripped down and serviced, as stated in gas safety regs, and in accordance with manufacturers instructions. 100ppm is fine especially if standard efficiency not high efficiency. CO2 ratios will vary with manufacturers but as a benchmark 9.2% +/- 0.5% will generally put you in the ball park.

not used a flue gas analyser in ages, iirc reading had to be 0.0040 or less

I assume your ex-trade then!

HTH

nb650