Co ratio gas fire

[Nostrum]

Have been doing some servicing and safety checks for a HA over the last few weeks, mainly boilers and cookers so all good. Had one yesterday with a gas fire and didn't think anything of it until the system we use asked for a flue analysis and then i realised I've never used a FGA on a gas fire before. Last time I did servicing on a fire they weren't readily used, just had to rely on the usual checks.

It ran up fine as you would expect with all the excess air but just wondering what the permissible figures are, is it 0.02 as stated for BBU with fire or am I completely missing where's it's written as I can't see it listed on the standards anywhere?

Cheers, Sam

 

[ambrosia]

where are you testing it and what type of fire, corgi book says dont test if you need to move the fire away from the closing plate making most fires impossible to test

I must admit i've never seen a test point on a fire,

as you said if its in combination with a backboiler its an unbelieveable 0.020
other than that corgi book only lists space heaters, (flued 0.020, flueless 0.001) no DFEs LFEs etc listed

 

[Nostrum]

Hi mate,

It was a robinson willey firegem so I just stuffed it as far up the hood as i could without melting the probe handle! Came back at 0.0002 or something silly.

 

[GrahamM]

How are you going to test an open DFE fire then? Bearing in mind it should be on for a good 5-10 mins to get it upto temperature?
Better get out the fireproof gauntlets!

With the exception of fluless, you do not need to FGA fires. If you have to put in a figure N/A or 0 in the box.

 

[AWheating]

you only have to fga appliances which require it in the manufactures instructions when servicing.

 

[arran197]

As has been said before, you don't need to FGA fires unless they're flueless.

 

[Nostrum]

I know I don't need to, i've fitted and serviced enough fires before a FGA was readily used to know that I don't need the machine to tell me it's safe!

The question was, if they ask for it, and it can be done I will do it, and what is the allowed readings in this case. I think 0.02 is the answer as daft as it sounds!

 

[AWheating]

you sometimes get asked to do something by a person in a HA who has no ideal what they are talking about. I have had gas certs refused because of some stupid reasons, when questioned you tend to have to try and explain the regs and requirements to somebody who just files them away and has no idea what they are on about.

Had one recently where i had to explain myself over and over again why i put N/A for spillage and flue flow on a room sealed appliance to a manager who had no idea what the difference is between flue types and there requirements.

 

[mountainman]

A little knowledge is a very dangerous thing IMO

 

[ambrosia]

you sometimes get asked to do something by a person in a HA who has no ideal what they are talking about. I have had gas certs refused because of some stupid reasons, when questioned you tend to have to try and explain the regs and requirements to somebody who just files them away and has no idea what they are on about.

Had one recently where i had to explain myself over and over again why i put N/A for spillage and flue flow on a room sealed appliance to a manager who had no idea what the difference is between flue types and there requirements.

oh the times theyve just given me an extra form to fill in just to make sure for definite it safe, this appliance just doesnt have enough forms filled in about it yet

 

[Nostrum]

It's not the HA directly it's the company I am subbing for, they have a system in place and they want it following. If that's what they want, they get it!

Common sense went out the window ages ago, if there's a box that needs ticking then so be it. I've given up trying to persuade or argue with people in defence for common sense and using a bit of initiative. Instead stubbornness and as you say above, a little knowledge will win every time when they pay the bills so that's the way it's going to be if that's what they want.

 

[GrahamM]

It's not the HA directly it's the company I am subbing for, they have a system in place and they want it following. If that's what they want, they get it!

Common sense went out the window ages ago, if there's a box that needs ticking then so be it. I've given up trying to persuade or argue with people in defence for common sense and using a bit of initiative. Instead stubbornness and as you say above, a little knowledge will win every time when they pay the bills so that's the way it's going to be if that's what they want.

So, what if you FGA an open flued fire. Ignoring the safe working aspects to do this and get a reading way off the scale. Bearing in mind most fires are designed to burn poorly to give a nice flame effect.
Are you going to cap the fire if ratio is 0.1000 and CO is off scale?

It is not required, so do not do it. N/A or Zero in the box. Simples!!

 

[stevetheplumber]

im with sam on this one unless your a fan of banging your head against a pebbledashed wall its a waste of breath trying to argue with the corporate system its usually their fga so wedge it in the fire then light it after you've burnt six or seven probes to destruction you might find a line manager whose budget is effected will ask why its happening stupid i know but thats the way it works now until it effects profits theres no deviating from the plan

 

[Nostrum]

Also its the shifting in liability you have to be aware of now.

If a situation arose were a fire had caused CO poisoning someone will be investigating and looking for someone to take account.

By measuring or in worse case scenerio notifying/issuing a warning notice the Co levels exceeding the allowance, my arse is covered. You can bet your life the HA will be waving the CP12 around like a get out of jail card, the company I sub for will be showing the system in place and my signature on the CP12 so the responsibility drops right into my lap.

A room sealed appliance is deemed at risk if the ratio exceeds the given allowance, so why take a chance on an open flued appliance which is far more likely to be a risk?

You could have a pre cast chimney pull fine one day and fail the next so until CO detectors become mandatory for open flued appliances (especially like the old firegem I checked the other day with no FSD) i'll cover my arse as best as possible.

 

[peteheat]

Spillage test and maybe check the room for Co?

 

[AWheating]

the problem with these methods shown by large companies is they think that a fga reading is now the only important thing. So they push engineers to do a reading and if its ok walk away. I have seen it alot, cast iron heat exchangers not cleaned because a reading was ok even though the MI require it to be cleaned. I know loads of HA engineers who service new WB Greenstars who dont follow MI and base there service on the fan pressure reading aswell as the fga reading but just off a fga reading. If its a service the Manufactures instructions should be followed not the guy in the office's instructions who wants you to fga the appliance and run to the next job to make as much money as possible.

 

[Nostrum]

I'm no mug and appreciate the limitations of an analyser, I served my apprenticeship before they were a common piece if equipment. I just struggle to understand this, if you don't have to do it then don't bother attitude. Technically there are very few appliances that require an analyser to service, all the non condensing combis around etc. I don't know about you but I find it gives me that extra re assurance that even after the visual inspection, cleaning and other tests, the FGA confirms that everything is tickedy boo.

I had a Worcester 240 BF the other day that checked out fine, pressures spot on etc no cause for concern. Analyser went way high when testing. Had 3 different engineers to check it over (was my first day subbing for this lot so don't think they trusted my judgement) and no one found a logical explanation for it.

My guess is that the previous maintenance contract company have done some work and something has been incorrectly replaced (injector maybe) and played about to get set up to MI but missed the poor combustion. Boiler was replaced, it was a heap anyway.

I do agree that i'm sure some people rely on the kit to much, but if you can get a reading, regardless of whether or not you have to, I don't see why you wouldn't. Belt and braces and all that.

If it isn't viable to do it, then so be it, I won't loose sleep over not doing it either.

 

[peteheat]

I agree where it's possible and or useful to use the FGA however I do remember when doing Gas safe (a long time ago) our instructor hammered home the importance of following the procedures in place, for example a decorative fire should get 5 minutes to heat up not 4 or 6 minutes but 5.

The man was very experienced with our standards (I.S. 813) which I understand are very similar to the UK standards, his point was if there was a problem with an appliance after we inspected / serviced it and gave evidence that we allowed 6 minutes instead of 5 the prosecution could argue we knew or had suspicion something was wrong and strayed from the set procedure to achieve the result we wanted.

We would not be able to argue the 6 minutes was because we went outside for a smoke or to the kitchen for a cup of tea because failing to observe the appliance for the time it was heating the flue could be viewed as negligence.

So I follow procedure or MI if their test is procedure and further safety measures, I'm not sure Head office instructions would be much better as a defence that the two outlined above.

 

[GrahamM]

Also its the shifting in liability you have to be aware of now.

If a situation arose were a fire had caused CO poisoning someone will be investigating and looking for someone to take account.

By measuring or in worse case scenerio notifying/issuing a warning notice the Co levels exceeding the allowance, my arse is covered. You can bet your life the HA will be waving the CP12 around like a get out of jail card, the company I sub for will be showing the system in place and my signature on the CP12 so the responsibility drops right into my lap.

A room sealed appliance is deemed at risk if the ratio exceeds the given allowance, so why take a chance on an open flued appliance which is far more likely to be a risk?

You could have a pre cast chimney pull fine one day and fail the next so until CO detectors become mandatory for open flued appliances (especially like the old firegem I checked the other day with no FSD) i'll cover my arse as best as possible.

I do not think you are grasping this.
A fire is a different kettle of fish. It is designed to burn badly to give a nice visual picture.
I have tested a few out of interest when FGA was first available. Most give ratios way off the scale. Most have no means of adjustment.
What are you going to do if ratio is way off???
Some of the worst were the balanced flue fires. Ratio way off even though I had just strip cleaned.

Strip clean the fire, clean the burner/injector, clean coals etc. put back together as per MI's, do your flue flow and spillage.
Job done!!!

 

[Nostrum]

Graham I'm fully grasping it thanks very much, i fully understand the principles of combustion therefore the use of a fga and the reading I get from it.

Of course you'll get foul readings from a DFE or similar, although the reasons the amanufacturers have such strict coal placement diagrams is to limit the effect they have on the combustion process. Funnily enough I served half my apprenticship with a company who specialised in decorative fires and surrounds so please don't speak to me like a child.

I asked the question so that if it can be taken under reasonable circumstances with an accurate result, what the tolerances are. You seem to have channelled your argument into using a specific type of fire to come to an assumption that fires in general are exempt. That's fine I won't try and persuade you to do any differant as technically it is not required, but Please don't make assumptions on my competence for going above and beyond the required practice. What you also have to bear in mind is that some regulations are purposely avoided because of manufactures tendencies in previous years. That doesn't make it safe by any means, just very difficult to change retrospectively.

I struggle to see how any open flued appliance can be allowed to spew out high levels of co in this day and age without at least co detectors being mandatory like that mow are for solid fuel appliances.

 

[peteheat]

Graham I'm fully grasping it thanks very much, i fully understand the principles of combustion therefore the use of a fga and the reading I get from it.

Of course you'll get foul readings from a DFE or similar, although the reasons the amanufacturers have such strict coal placement diagrams is to limit the effect they have on the combustion process. Funnily enough I served half my apprenticship with a company who specialised in decorative fires and surrounds so please don't speak to me like a child.

I asked the question so that if it can be taken under reasonable circumstances with an accurate result, what the tolerances are. You seem to have channelled your argument into using a specific type of fire to come to an assumption that fires in general are exempt. That's fine I won't try and persuade you to do any differant as technically it is not required, but Please don't make assumptions on my competence for going above and beyond the required practice. What you also have to bear in mind is that some regulations are purposely avoided because of manufactures tendencies in previous years. That doesn't make it safe by any means, just very difficult to change retrospectively.

I struggle to see how any open flued appliance can be allowed to spew out high levels of co in this day and age without at least co detectors being mandatory like that mow are for solid fuel appliances.

Perhaps the unhealthy involvement of the gas companies (both British and Irish) in the sale and installation of decorative gas fires could signal why a C0 detector is not mandatory in the room?

Personally I wouldn't have one in my home after a near miss many years ago when the flue was blocked but the fire worked with no visual effect, yes they have the potential to be very dangerous, I have seen them installed in houses where a normal open fire would not work due to down draughts, it was a case of don't inspect when the wind was blowing from a certain direction.

While they have the obvious potential to be dangerous I think the flueless models are worse especially as so many customers are failing to have an annual service carried out and many are blocking the vents.

I agree there is a very good case for C0 detectors to be fitted with all decorative fires.

 

[Nostrum]

I agree Peteheat and have also seen cases where fires have been installed on precast chimneys and worked fun day and failed the next, in fact there at whole estates full of them. I fitted a fire for said company above and we had to dismantle the twin wall flue in the loft to clear cob webs and crap out to get it to pass a flow test etc. A few years later I had actually changed employers and by co incidence we had a boiler replacement in the same house. The scheme we were installing for aske for all appliances to be tested while we were there and this particular fire failed again. It was quite embarrassing to tell them I had to disconnect and in the next to mention I fitted it!

You just never know what can happen and given the fact if any thing goes wrong the POC will end up straight back in the room your sat in, I would rather limit the risk as best as possible.

Also I presume the reason for fires having a higher acceptable reading is because of the mentioned effects for a nice flame picture as strictly speaking there is no reason to have poor combustion with a radiant gas fire.