CPA Analysis - acceptable readings

[lordyjordy111]

Hi all

does any one know the acceptable cpa levels for a boiler. I've just done a course at gas logic and the book that I got from them says if the ratio of co/co2 is above 0.008 then this should be investigated as it is not burning as it should.

fairly simple stuff but I had a boiler today which gave a reading of 0.0042 which I thought was fine.

however the engineer who i was working with said anything 0.004 or above needs a service???
my book says nothing about this???

also, does anyone have a view on the viper gas books as the book i have seems to omit vital info like discussed above.

thanks

 

[Gray0689]

Hi all

does any one know the acceptable cpa levels for a boiler. I've just done a course at gas logic and the book that I got from them says if the ratio of co/co2 is above 0.008 then this should be investigated as it is not burning as it should.

fairly simple stuff but I had a boiler today which gave a reading of 0.0042 which I thought was fine.

however the engineer who i was working with said anything 0.004 or above needs a service???
my book says nothing about this???

also, does anyone have a view on the viper gas books as the book i have seems to omit vital info like discussed above.

thanks

0.0042 is fine

 

[lordyjordy111]

so it doesn't need the burner cleaning or something like that?

 

[Barry98]

you could do it to see it improves its , but theres no rule says you have to . we do a before and after reading

 

[CMairiD]

0.0042 is fine

Just worth noting that some manufacturers have a more stringent criteria for the ratio. Additionally, they may ask you to look at min/max CO[SUB]2[/SUB]%.

It's also worth looking at TB 126.

 

[lordyjordy111]

what is TB 126??

 

[johnnyplumb]

as general guide the action levels for boilers are- 0.004 before a service & 0.008 after a service but heres a question specifically for you lordyjordy111, why are you allowed a higher ratio ie 0.008 after servicing/cleaning.

 

[CMairiD]

TB stands for technical bulletin. They are produced by Gas Safe.

In this case, the TB recommends that boilers with air/gas ratio valves do not exceed a ratio .004 and if they do, they are considered AR. If exceeding .008, then ID.

But again, this is subject to MI. For instance Worcester Bosch Ri, are looking for a ratio of no more then .002. Any thing exceeding that requires a service.