Who said analyzers were accurate?

Bob Sweet

interesting to say the least that the same people who have touted the mandatory use of a combustion analyzer " If you dont test you dont know" are now questioning the trustworthiness of the equipment they have been glorifying. No dissrespect intended but very odd.

I dont deal with oil because there is none. Nat. gas and propoane are what we use. For me the proof is in the pudding. Primarily I deal with condensing boilers, without the analyzer forget about ever getting these things to run, they wont. So for me it is an indespensible tool. If I didnt use it I couldnt do my job.


If indeed the analyzers are as inaccurate as stated by others then the liablity issues of having it calibrated and printing out each test as proof goes out the window.

I dont blame you Dave for thinking about tossing it in the corner. All these statements throw a cloud of doubt as to the reasons to own one. Personally I have doubts about their doubts. I am by no means an expert and am not challenging their results but can only say that for me in the field using the tool daily it works. If only to get the equipment into a combustion realm of working to manufacturers specs.


Most of us are not engineers, we can do what we can do to provide a professional assessment of proper working conditions of a given piece of equip. I dont think that can be done without the analyzer. To quote the Monkees " I'm a believer".


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jp_2

good topic for discussion

Tim, in early spring you posted several different analyzers measurements, can you pull that info back up? I can't seem to find it.

jim davis, if these thing are so inaccurate why bother to calibrate them? so if you measure a calibration gas everyday you get vastly different readings?

Glen

let me toss the first stone -

into the pond that is - and create the first ripple.
There may be some anecdotal evidence - that not all analyzers are created equal. We can use a number of criteria to determine that: price point, source of origin, components used, rep of mfgr, quality of annual service, storage habits of user, etc. I use two on a regular basis, a bacharach and a Kane may. Each will give me slightly different readings on a constant source of flue gas (well tuned CT3 with Weishaupt burner for instance). Is that enough to throw up my hands in confusion? No it is not. Why you ask? Because of all the variables one must consider. Atmospheric pressure, quality of fuel, calorific value of the fuel, condition of the appliance etc. One sample of flue gas is not definitive - a record of annual maintenance, listing the past 5 or 6 years of analysis could be. And that is why we also calibrate regularly - it is a risk management detail that needs attention, using your analyzer until it breaks down is not acceptable.
Now I know this will be an interesting thread - but it is my opinion that the use of an analyzer is critical to our industry. I am further opined that basic features are not enough - and not just to add sizzle to the steak but to give us and our clients meaningful information (note I did not say data).
Calibrate annually - to ensure that your information is meaningful, accurate is a term we should use prefixed by the term - relative. Relative to the given conditions of the day and the history of the appliance.

Steamhead (in transit)

\"the use of an analyzer is critical to our industry\"

I couldn't have said it better! This is a BASIC TRUTH.

Even if there's a bit of hair-splitting between different analyzers, any digital analyzer in good condition will tell us if the unit is operating safely and at its best efficiency.

For those of you who don't have an analyzer yet, GET ONE and LEARN HOW TO USE IT. When you find your first unit that's making excessive CO, the analyzer will have justified itself since you will likely have saved someone's life by using it.

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Jim Davis_3

inaccurate but very dependable

I have a watch that never has the exact time, but it is dependably inaccurate. I can interpret what it is indicating and still be on time. I bet if you checked 10 peoples watches they would all have a different time. Analyzers are the same way. They operate within an acceptable inaccurate range no matter how they have been calibrated. Flue gasses are considerably different than lab test gas. I have personally calibrated thousands of analyzer over the past 25 years, and many different makes, so I am pretty familiar with their performance. It is the person using it that determines the true accuracy. The CO sensors are the biggest discrepency but when they are in error it is usually always on the high side which is not an unsafe condition.

As steamhead said you have to learn how to use them and become familiar with the readings they actually measure. Most of the time you can ignor anything they calculate because it is based on data and input that is not usually found in the field.

I can easily check the calibration of most analyzers with my breath which could be why everyone is always offering me breath mints, but that a different matter.

Glen

Jim -

may I ask if the mints affect the CO readings? :-)

Josh M.

I have owned about 5 different analyzers and not one has been accurate 100% of the time.

When working on a boiler where a tenth of a percentage point can be crucial such as one over 600HP I check the analyzers accuracy with a CO2 shaker. I then re-calibrate the analyzer to the proper levels. I don't think however you can manually calibrate with some of these cheap analyzers that are out there.

The old stuff never lies. Just remember you can't take a CO2 shaker on the airplane. I found that out the hard way.

jp_2

determine inaccuracy?

how do you determine it is not accurate, without measuring known value?

Josh M.

By comparing with a shaker or tester gas..

jp_2

shaker?

whats a shaker?

Unknown

I just bought,

my first one,,, and still trying to figure-out how to use it properly,,, but you guys are now making me doubt my purchase decision!

Perhaps I should have just bought a bunch of beer for my guys?,, bet they would like that better.
Like I said before(Frank & Alan), another tool I`ll "throw in the corner", and likely never use.

Dave

Unknown

jp

I "think" he means the old C02 shakers for mixing drinks(with booze), they have an injection cartridge, old movies called them "seltzer", if I remember right?
Most comedians in the 50`s used em for a laugh, then they resurfaced in the 80`s.

Dave

burnerman_2

upper edge

I have a tester and as others say are they worth thier time. Well if you have an educated customer and he or she says are you going to do a combustion test? You say yes in deedy stick the jigger in the whole and read off the numbers. Gives you the upper edge in a competive market. sorry grammer is not a strong point royboy

bob_46

Dave and JP

A "shaker" is a gadget that uses the Orsat method of analysis involving chemical absorbtion of a sample gas such as carbon dioxide or oxygen. The reagent used to absorb CO2 is potassium hydroxide, and chromous chloride is the absorbent for O2. A lot of burner techs carry them on the truck to check their electronic analyzers. I don't recommend drinking this stuff or spraying it around. bob

Paul Fredricks_8

Was how inaccurate ever mentioned here? I calibrate all of ours every 6 months. I have not found one yet that was spot on. That said, I don't think any were out far enough to really be a problem. I don't think it matters to many if the CO air free is 29 PPM or 35 PPM. Or if the stack temp is off by 3 degrees, or if the O2 is wrong by .3. I haven't placed a lot of faith in the draft reading I get with the Bacharach 125 and always back it up with another gauge.

For my money these are a MUCH better way to go than the old wet kit, and worlds better than adjusting by eye. In the 3 years our company has used them we have not had one sooted up house due to the tech not adjusting the burner properly. Instant savings to the company in the area of insurance premiums.

Bob Sweet

Point taken Paul

After actually reading the thread I jumped the gun on my post.

I do spend a lot of time going in after contractors and testing boilers for reps and wholesalers. The equip. gets a bad rap because contractors fail to see the benefits and necessity to test these boilers. I cant see how anybody can sleep at night without using an analyzer.


I stand corrected.

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Steamhead (in transit)

Dave, if as Paul says

the differences are "the CO air free is 29 PPM or 35 PPM..... the stack temp is off by 3 degrees, or if the O2 is wrong by .3.", then it's really not enough of a difference to matter.

The point is, you'll be using the same analyzer, or one of several analyzers of the same make and model, to test your customers' equipment year after year. If something changes drastically from one year to the next, you'll know to investigate further.

Sure, we all have our favorite analyzers, and debates like this are a good indication that more of us are using analyzers. But this kind of hair-splitting is counterproductive, to say the least. It's much better to have an analyzer that may or may not have a slight error as Paul describes, than not have an analyzer at all. Even Jim Davis concedes this point.

DON'T stick your analyzer in the corner. USE IT!

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Jim Davis_3

The biggest discrepency on analyzers is the CO readings not the O2 reading. These are rarely off more than .2% unless your hose or filter leaks. They self calibrate every time you use them. The CO is different because of sensors but worse case they always read high which is not unsafe. Temperature in flues can vary 50 to 100 degrees depending on the size of the flue. Our job is to use consistency in the method we test with any analyzer to get repeatable readings.

In class it has been common to have 3 or 4 different analyzers in the same flue or heat exchanger simultaneously. The only reading that is close is the O2.

The old shakers, Fyrite bottles or Orsat were easily off .5% or more most of the time. Because you have to traverse a flue to find where to test in the first place makes most of them just a random test. Unless we know the actual CO2 content of the fuel we are testing, the CO2 reading is not accurate just approximate. O2 is the most dependable. The CO2 on analyzers is calculated only and most of the time mis-calculated.

Paul Fredricks_6

CO

Hey Jim, how do I know if the CO sensor is bad, or going bad, on a Fyrite 125 Pro? The O2 is easy to figure out as it has a health reading at start up. And I haven't changed out a CO sensor yet.

Consistent test method is nearly impossible with the various test hole locations, models of heating system, and 40+ tech doing the tests at different times of the year. But I know what you mean.

Jim Davis_3

Touch the end of the probe with a flame for 1 second. If the CO jumps to 100 - 200ppm or somewhere in that range it is good. A smoke exhaling into the probe(not while smoking)will raise the CO reading between 15 - 30ppm.

If you get no response the sensor is bad or if the meter pegs with the match it is probably bad. Other than that it is just fine. The most important CO reading always is if it is stable versus rising.

Paul Fredricks_6

I've had techs complain about getting bad readings (in the 1000's). When I get them back and hook the unit up to the 500 PPM bottle everything checks. Seems to me like tech error.

I guess these sensors either work or they don't.

Steamhead (in transit)

If it was \"stable\"

at 1000 PPM, I'd say that's a problem........

"Steamhead"

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Paul Fredricks_6

I agree

From what I've seen here are the possible reasons:

1. The unit is moist and they haven't given it enough time to dry out. The moisture really drives the reading up.

2. Cold units that haven't been given enough time to achieve steady state.

3. Possibly air leaks in old cast iron boilers.

For some reason the techs always seem to think they need to get out of the house as fast as possible, no matter how many times we tell them to take the time to do it right.

Jim Davis_3

They can over respond but that would happen on the test gas also. Moisture would more likely cause it not to read than over read because it can plug the membrane on the sensor and not allow the reading to get through. As long as the analyzer is warmer than 32 degrees, I have not seen that to make a major change in the CO reading. Temperature affects the batteries more than the sensors and this does cause a slight drift, but not enough to create major errors. No one that I know has tried to abuse analyzers more than I have just to determine what messed them up. I know mints don't make any difference either.

If they are reading 1000ppm it is most likely because that is what the appliance is making. Maybe some told them blue flames don't make CO?

Paul Fredricks_8

The main reason it's something else is that when the techs have a high CO issue they can't solve, I'll send another tech the next day and everything tests fine. My thought was that the moisture steaming off was affecting the flame. Next day it's all gone.

Just a theory.

Mad Dog_2

.......BUT FRANK......THAT COSTS ALOTTA $$$$$$$

...WE HAVE ENUFF TROUBLE gettin paid.....' YOU 100% CORRECT, sTEAMHEAD!!!!!!....stop SPLITTTING HAIRS AND DROWNING IN THE EXTRANEOUS, MINUTE, SCANT DIFFERENCES BETWEEN METERS AND READINGS...guys...SOMETIMES YA GOTTA GET YOU A GOOD HOBBY....ASIDE FROM NIT-PICKIN. MAD DOG

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Mad Dog_2

unshakeable.....................................................

Jim Davis is! Love that man. Mad Dog

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Jim Davis

Sometimes without all the readings things can be really hard to explain. O2 & Flue temperature are always critical and it is important to check the O2 every minute to make sure it is not fluctuating. Most serious CO problems are intermittent but the actual sypmtoms should be recognized 99.9% of the time. Never seen steam or vapor interfer with the readings but never say never because that ain't so!!

Bob Sweet

Jim

You say "The CO2 on analyzers is calculated only and most of the time mis-calculated."

So for techs dealing with condensing boilers for the most part, manuf. specs are most concerned with CO and CO2 production (some with O2 not many). Seems a bit tough to dial them in if CO2 is mis-calculated. (for clarification is it the analyzer or interpretation of readings that is mis-calculated ?).


After battling MANY boilers to dial them in it seems as though CO is a much more reliable median than CO2. Add elevation to it and manuf. specs can be thrown out the window. (With regards to CO2 levels).




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Jim Davis_3

When fuel is burned it produces 99.99% of its ultimate CO2 content if CO is less than 100ppm. This CO2 is then diluted by excess air or O2. Unfortunately the CO2 content of the fuel varies with the btu content of the fuel. 950 btu per cu.ft. has a different CO2 content than 1050 btu per cu.ft. Guess what happens when we get to higher altitudes and the btus are even less!

Our job is to dilute the CO2 the least we can by using up all the O2 in the combustion process as possible. Sometimes we adjust air and sometimes we adjust fuel. CO & flue temperature determine the limits of how far we can go.
O2 gives us a clue of how much change or improvement we actually made.

All analyzer assume the CO2 content of the fuel is the same at all times. Some can be reprogrammed if you know the actual btus, but they are what they are. Keep O2 low, CO2 will be high.

Glen

Keep O2 low, CO2 will be high.

with the caveat - if CO is acceptable.