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.

 

[AWheating]

you can lose 1.5mb according to the manufacture, i still have not fitted one that has had a 1.5mb drop. I always have gotten less than 1mb between meter and boiler test point........ maybe im just lucky or cant use my gauge?

 

[REDSAW]

yes i am, ian fowler reg no 3114

do you watch 'eastenders'?

 

[galaxy_plumbing]

that really helped him Red 😀

 

[Millsy 82]

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.

This is what I do

Run the boiler for 30 mins then do your analyser check by this time most of the coatings inside the heat exchanger will have burnt away in the 1st 10mins of running then check it. Otherwise all of the LPG boilers are going to be set incorrectly. (Try it next time you convert an LPG if you dont like your analyser I maxed out my analyser ran it for another 20 mins used another analyser and it was about 50PPM It was an expensive mistake to make)

My reasoning behind this is if it is a mile out in a years time what do you think its like at 2-12 months its going to be pretty much the same and if its spewing out 400PPM in that time you have no way of knowing it.

I know you dont have to it just gives me piece of mind and 1 day you will have to.

All manufacturers tech lines can only tell you whats written on the screen in front of them and then unless you get a good 1 they strugle with that half the time.

 

[Danv44444]

thanks milsy 82

 

[M77]

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.

Surley though you would perform a f.g.a as part of the commissioning process where they usually ask for co2 % or co/co2 ratios as part of the commissioning benchmark?
Although you would have done gas rates the f.g.a would give you information on the safe operation of the applience along with any defects you might not see.

 

[Dannypipe]

Whatever did we do before we all had combustion analysers!?

What is the point in recording the ratios, if they're out and when you call the manufacturers to discuss it, they say we shouldn't do a combustion test on commisioning as the lining of the combustion chamber will throw the results out?

The benchmark has lots of other information which might also not be rellevant. A standard form is printed in the back of every boiler hand book whether it's a system or a combi, or a heat only.

I'll do one if it's required. If its a new appliance, and its doing what it should regarding gas rates and burner pressures, then the chances of an issue are very slim. I would do one if I felt it appropriate. Which I often do.

Milsy, are you saying you broke your C/A doing a test on a new boiler, but after letting it run for half an hour and using another analyser you got OK results?

 

[M77]

True. And yeah the chances of anything being wrong are very unlikely.
Although in the past we weren't fitting boilers with forced draft burners where the burners are hard to see/access. ( viessmann for instance)
I' ve found running the applience for 10-30 mins burns away any coatings and the readings are within the M.I's tolerances.
i thought from April this year combustion analysis should be carried out on all boilers, although if this applies to commissioning I'm unsure?

 

[Dannypipe]

I take your point and agree to a greater extent.

I can't say with any confidence whether it does apply to commissioning too. If it does then I will do as you suggest and burn it off for half an hour before doing a C/A.

 

[Millsy 82]

Whatever did we do before we all had combustion analysers!?

What is the point in recording the ratios, if they're out and when you call the manufacturers to discuss it, they say we shouldn't do a combustion test on commisioning as the lining of the combustion chamber will throw the results out?

The benchmark has lots of other information which might also not be rellevant. A standard form is printed in the back of every boiler hand book whether it's a system or a combi, or a heat only.

I'll do one if it's required. If its a new appliance, and its doing what it should regarding gas rates and burner pressures, then the chances of an issue are very slim. I would do one if I felt it appropriate. Which I often do.

Milsy, are you saying you broke your C/A doing a test on a new boiler, but after letting it run for half an hour and using another analyser you got OK results?

Yeah it killed my analyser wouldnt pick up any CO after that. But lesson learnt.

 

[Barry98]

do you watch 'eastenders'?

sweet

 

[Dannypipe]

Yeah it killed my analyser wouldnt pick up any CO after that. But lesson learnt.

Costly mistake. I guess it overloaded the sensor? I dunno, I'm no expert with these things.

Did it get repaired?

 

[AWheating]

Surley though you would perform a f.g.a as part of the commissioning process where they usually ask for co2 % or co/co2 ratios as part of the commissioning benchmark?
Although you would have done gas rates the f.g.a would give you information on the safe operation of the applience along with any defects you might not see.

leave that part of the benchmark blank or even better put n/a. The benchmark does not overide MI.

but dont get me wrong i would do a test but you dont have too.

 

[kirkgas]

True. And yeah the chances of anything being wrong are very unlikely.
Although in the past we weren't fitting boilers with forced draft burners where the burners are hard to see/access. ( viessmann for instance)
I' ve found running the applience for 10-30 mins burns away any coatings and the readings are within the M.I's tolerances.
i thought from April this year combustion analysis should be carried out on all boilers, although if this applies to commissioning I'm unsure?

there is still confusion over what CPA is all about, the bottom line for any appliance is that it MUST be commissioned as per the MI, so of the new appliances you have fitted since april how many of them DEMAND you use a FGA when commissioning and how many tell you that the checks are not required

 

[M77]

Non of these appliences demand c/a but at the same time I've never seen m.i stating c/a is not required for commissioning. I know on some boilers in the commissioning section of the m.i they specifically ask for co2%. How else would you know this unless you used a f.g.a?.
The same goes for filling in the bench mark. Why would they ask for these readings if not needed? They ask for gas rates, flow return temps etc, but we fill them in. If the info related to f.g.a is not needed to be filled in then why bother filling in the rest? Why not just turn on and walk away.
There does seem to be a lot of confusion over c.p.a 1. And I'm unsure myself. Why would Gas safe stop engineers from carrying out certain gas work if they hadn't completed their c.p.a 1 by April this year. If F.g.a was not nessercery for commissioning and engineers where only installing boilers etc then what's the point of doing it as it wouldn't be needed? Maybe its just the way I've interpreted c.p.a 1 and when you must carry out c/a.

 

[tamz]

Take your pick from your favourite boiler mi's.

Worcester

NOTICE: The combustion settings on this
gas-fired boiler have been checked, adjusted
and preset at the factory for operation on
the gas type defined on the data plate.
No measurement of the combustion values is
necessary provided there is a meter installed
allowing the gas rate to be checked.
DO NOT ADJUST THE AIR/GAS RATIO VALVE.

Vaillant

The boiler is supplied ready adjusted and no further gas
adjustments are necessary, however both the gas inlet
working pressures and maximum gas rates should be
checked as detailed in 5.9.2 and 5.9.3.

Ideal

General
Please Note: The combustion for this appliance has
been checked, adjusted and preset at the factory for
operation on the gas type defined on the appliance
data plate. No measurement of the combustion is
necessary. Do not adjust the air/gas ratio valve

etc etc.
Viessmann do ask you to check it tho.

If you read the benchmark it says, where required by the manufacturer, record the following......Some do but most don't.

What is the point of doing it indeed for new install work. Probably 75% of boilers are installed by guys with no access to a fga and who have no need to have one and the next time they see one will be in a classroom in a few years time.

 

[M77]

Interesting. Might start fitting wb! Save me some time. 🙂

 

[AWheating]

Interesting. Might start fitting wb! Save me some time. 🙂

or Ideal, continued work for the 3-4 year of its life.

 

[tamz]

or Ideal, continued work for the 3-4 year of its life.

I've fitted a good few Logics after being persuaded over a game of golf and a free lunch (what a **** i am :lol🙂. I was very sceptical to begin with but so far (touch wood) there has been no problems. It is a decent enough boiler but fkn ugly imo

 

[mcniven]

I've fitted a good few Logics after being persuaded over a game of golf and a free lunch (what a **** i am :lol🙂. I was very sceptical to begin with but so far (touch wood) there has been no problems. It is a decent enough boiler but fkn ugly imo

Haha ..

 

[AWheating]

I've fitted a good few Logics after being persuaded over a game of golf and a free lunch (what a **** i am :lol🙂. I was very sceptical to begin with but so far (touch wood) there has been no problems. It is a decent enough boiler but fkn ugly imo

nothing wrong with a free lunch LOL.

 

[Nostrum]

and I always thought there was no such thing as a free lunch....!