co /co2 ratio

[ian1965]

i have just commissioned a worcester 28i junior on the combustion test i obtained an 02 % of 4.1 and CO2 %reading of 9.6 with co ppm of 82 giving me a ratio of 0.0008 with the above reading operating the boiler on maximum via the service button, with the boiler operating on minimum i had a CO2 reading of 8.4% with a ratio of 0.0002, slightly confused as boiler manual states of CO-less that 200pmm (0.0002)?

 

[Millsy 82]

Are you GSR?

 

[CES]

This thread should be on the GSR forum IMO.

 

[ian1965]

yes i am, ian fowler reg no 3114

 

[ian1965]

new to this have been told thread has now been moved

 

[Millsy 82]

The CO will come up like 82 PPM
The ratio is the 1 that looks like 0.0002
So apart from the minimum CO2% being too low the others look ok

 

[Dannypipe]

On newly installed Worcester Bosch's you don't perform a combustion analysis unless it's LPG and you can't gas rate it.

 

[Dannypipe]

Sorry is this now in the GSR section???

 

[Millsy 82]

Although you dont have to carry out a FGA reading on the boiler it is best practice to as I have commissioned brand new boilers which have been 10.5% and higher. For the sake of 5 mins atleast you know it is burning correctly.

 

[ian1965]

i feel this doesn t answer my query. also i believe the minimum co2 reading is not too low as the manual states 8.8%+ or -0.5

 

[ian1965]

those were my thoughts excatly!

 

[Millsy 82]

i feel this doesn t answer my query. also i believe the minimum co2 reading is not too low as the manual states 8.8%+ or -0.5

It seems I was wrong the newer models are 8.8+/- .5 ahwell ive still set them all in the correct ranges.

The CO/CO2 ratio will be displayed as the 0.0000 number and the CO PPM will just bring up a number. What your doing is using the CO/CO2 ratio for CO they are 2 seperate things.

 

[Dannypipe]

My point was, it's somtimes OK to have readings that aren't bang on when fitting a new WB.

I had the same scenario, called the manufacturer and was told that the results didn't matter as the boiler was brand new and would take a while to burn off coatings from the combustion chamber that may throw the results.

It must fall inbetween set ratios on its first service. The most importnant thing is to gas rate and check the burner pressure on the boiler. If these are OK, you dont need to concern yourself with the CO until its first service.

As said, this doesn't work with LPG as you can't gas rate it, so you have to check the flue gasses.

 

[AWheating]

i have seen plenty of new WB's have poor reading on inital use, am im talking running for a while not first hour or two.

 

[Danv44444]

On newly installed Worcester Bosch's you don't perform a combustion analysis unless it's LPG and you can't gas rate it.

Is that right Danny I thought you were supposed to combustion test all new installations?
Is it just wb that you dont have to?

 

[Dannypipe]

Yup, since I had that first initial one, I've seen it again a couple of times. Its nothing unusual and I don't think it's anything to worry about. If it's been in a year, then yes, worry about it!!

 

[Dannypipe]

(In reply to DanV4444444) Not just WB, other manufacturers too I think. I just read the manufacturers instructions. Often while on the toilet!! LOL.

 

[AWheating]

most manufactures still do not require you to perform a analyser test when commissioning a new appliance. If they do not require one then its your personal choice if you feel its better to do one or not for peace of mind.

 

[AWheating]

(In reply to DanV4444444) Not just WB, other manufacturers too I think. I just read the manufacturers instructions. Often while on the toilet!! LOL.

its funny you say this danny, i have a WB junior instruction manual next to my toilet currently aswell as the new gs mag. Best time to read 🙂

 

[Danv44444]

Thanks guys. One other thing i have found on wb boilers is that you lose 1.5mb of working pressure through the gas valve. It threw me a bit the first time a tested the pressure.