air fuel ratio

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  #1  
Old 01-11-19, 04:56 PM
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air fuel ratio

air fuel ratio question.

On my oil heater adjusting the air band and shutter I see the flame getting larger and larger as i decrease the air. Set to the smallest air intake the flame is the largest. I never see smoke.

I did a complete tune up last season and noticed this condition, then and again this season.

Your thoughts?

thanks,
paul
 
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  #2  
Old 01-11-19, 05:53 PM
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With these new retention head burners you rarely can see smoke with the naked eye unlike the burners of old. The burner manufacturer will give you recommended settings in their spec sheets but the only correct way to set up an oil burner is with a combustion analyzer.

The fire gets larger because of the lack of air and excess fuel mixture. The addition of air cuts the size of the fire down.

Hope this helps a little.
 
  #3  
Old 01-11-19, 06:15 PM
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I need to do by eye (The message you have entered is too short. Please lengthen your message to at least 25 characters.)
 
  #4  
Old 01-11-19, 06:51 PM
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You cannot properly set a burner up with just the naked eye. A combustion analysis is mandatory.
 
  #5  
Old 01-11-19, 07:14 PM
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If you must do it by eye and I do not recommend it, I would get the burner manufacturer's spec sheet and follow their suggestion. These settings are the best results achieved by lab testing their burners.
 
  #6  
Old 01-11-19, 07:40 PM
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manufacturer's specs are by gauge
 
  #7  
Old 01-11-19, 07:43 PM
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What is it your trying to achieve here?
To adjust and test your oil burner, a combustion analysis is absolutely mandatory. There are no other methods to it.
Ive been working in hvac for 18 years and I would never even attempt to set a burner by sight and sight alone.
 
  #8  
Old 01-11-19, 09:06 PM
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Try this sight if you have a Beckett.

https://www.beckettcorp.com/wp-conte...Spec-Guide.pdf
 
  #9  
Old 01-12-19, 05:57 AM
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How did they do it before they invented co meters?
 
  #10  
Old 01-12-19, 06:10 AM
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They had these. Old mechanical combustion test kit. Old school.
 
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  #11  
Old 01-12-19, 05:23 PM
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I thought old timers did it by sight.

what is the easiest meter to use.
 
  #12  
Old 01-12-19, 05:48 PM
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Sight tells you very little about what’s going on in the combustion chamber. For example, a gas furnace may have beautiful blue steady flame. But a test may show that blue flame is burning with 40 PPM CO.
Depends on what you want.
The old style ones can get you close and can be had for probably $100 and up used.
The newer digital combustion analysis equipment can provide much more information much quicker, but you’ll pay $500 and up for one.
It should be noted that both styles require calibration, although a homeowner can likely get by only calibrating equipment every few years.
 
  #13  
Old 01-12-19, 05:53 PM
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how do I shop for an old style one? What am I looking for? I know how to shop online, but I have not a clue what Im looking for.
 
  #14  
Old 01-12-19, 06:12 PM
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Honestly, before spending money, and not really knowing how to dissect the data a combustion analyzer gives you, have you considered getting someone like your fuel oil supplier to do your testing? Let them buy the expensive test equipment that you’d only use once a year.
eBay has lots of various combustion test equipment. But it’s a mixed bag of used equipment in various shape.
 
  #15  
Old 01-12-19, 07:01 PM
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I've had it tuned up many times and gotten ripped off each time. Every year I had to look for a new service tech cuz the old one was out if business. They never cked draft and always set it way too lean.

My old oil delevery man don't do tune ups and I stopped use him once I learned that off road diesel is exactly the same and I can by that for 1/2 the cost.
 
  #16  
Old 01-12-19, 07:13 PM
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Well, it’s been years since I used a old style kit. Your kinda at risk for whatever you get from an eBay seller.
This is one of the meters I use.

https://www.trutechtools.com/0563-3372-71

How did you know it was set too lean if you didn’t have a meter to check it?
 
  #17  
Old 01-13-19, 05:43 AM
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Let me add my 2 cents. Off road diesel fuel is cheap and in Pennsylvania is "illegal" to use for heating or for an on the road vehicle since it free of a lot of the taxes. If you can buy it OK but keep it to yourself since it may not be legal where you are located. As far as being cheap, make sure that the fuel you are buying is for diesel engines and is not some "JUNK" fuel that is sometimes sold. Years ago a neighbor bragged about the cheap fuel he was buying and it cost him a lot of money when he got a bad load. I have said this before; try to find a good service company, they will serve you well. These units can be set up close to optimum with the naked eye but it takes a lot of experience. If you really want to "do it yourself" and I would not recommend it since you need more than a good reading to do a correct job, go buy a smoke spot detector. I used this on the units I serviced with BTU inputs of 30,000,000 BTU'S and they did a good job. They do not cost a lot of money and will do a good job.
 
  #18  
Old 01-14-19, 04:16 PM
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"How did you know it was set too lean if you didnít have a meter to check it? "

it now heats the house 3x faster and cycles off sooner each time.

plz look at these videos of my flame and comment:

https://imgur.com/a/FyTEH7R

and

https://imgur.com/a/QCM7pXf

these are both at the same A/F ratio.

thanks,

paul
 
  #19  
Old 01-14-19, 04:29 PM
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Quick cycling results in inefficient operation and increased soot build up, and is not recommended. The goal here is letting it run long enough to stabilize combustion.
This will net the best fuel economy and efficiency.
I canít tell anything with your photos. But a combustion analysis will give you more information then you know what to do with.
But with your description Iíd say your way overfired.
 
  #20  
Old 01-14-19, 05:15 PM
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I was not implying 'quick cycling', just less on time then before I made my adjustment. The house gets warmer faster and the unit stay on less each cycle.

Reading over the manufacturer's (beckett) "Set combustion with instruments" It says:
Adjust the air shutter/band until a trace of
smoke is achieved.
Increase the air to reduce the CO by 1.5 to 2 percentage points.
Recheck smoke level. It should be Zero

The air handler (carrier) "Combustion Check" says:
"1. A test kit to measure smoke, stack draft, over-fire draft, oil pump pressure, CO2, and stack temperatures MUST be used in order to obtain proper air band setting. Although all of the above measurements are required for optimum setup and efficiency data, the most important readings that must be taken are smoke number, over-fire draft, stack draft, and pump pressure.
2. The proper smoke number has been established by engineer-
ing tests to be between 0 and 1. This degree of smoke emission
is commonly referred to as a"trace′′of smoke. It is recom-
mended to use a Bacharach true spot smoke test set or
equivalent."

tks,pa
 
  #21  
Old 01-14-19, 05:19 PM
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so if i just set smoke and WC?

after complete tune up, of course
 
  #22  
Old 01-14-19, 05:30 PM
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P,
By your photos the first one is with too much air which lowers the temp of the fire and gives you a very inefficient burn.

The next pic with the larger fire is because you cut the air back, causing a higher temp fire and a more efficient burn which is better.

As was mentioned though without an analyzer there is a fine line between an efficient burn and a lack of enough air, creating a sooty burn which really can't be determined by eye.

Just read other posts, must have crossed. The most important thing to me in my opinion is the smoke test and the draft. Those you have control over. If you get that right the rest takes care of itself. The other numbers are good to look at but they are what they are.

With the right draft and a clean fire you've done the best you could.
 
  #23  
Old 01-14-19, 06:17 PM
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both are the same air setting which is almost completely closed.
 
  #24  
Old 01-14-19, 06:54 PM
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https://www.amazon.com/s/ref=nb_sb_n...charach+smoke+

why the massive cost differences?
 
  #25  
Old 01-14-19, 07:20 PM
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P,
You're going to have to do a homework here on your own and read the description of what you are getting from the seller and not just look at the pic and the price.

I looked at the 34.00 one and if you read the add it says you do not get what the pic shows but just a part. Do not know what they mean but obviously for 34 I doubt it much. The prices may be all over the place because your getting them on the secondary market so do your homework.

Ebay is another source.
 
  #26  
Old 01-15-19, 08:39 AM
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thanks. what about other brands?
 
  #27  
Old 01-16-19, 07:57 AM
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For DIYer with oil burner the $100+ smoke spot tester is the way to go. There is little difference in brands.

DIYers do not need combustion analyzer to adjust oil burner air setting.

The smoke spot gage is easy to use. Adjust burner air until there is trace of smoke, then back off air until zero smoke.
 
  #28  
Old 01-16-19, 08:26 AM
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This is not entirely true, as then the user has no way of determining if the burner is overfired.
 
  #29  
Old 01-16-19, 04:55 PM
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please explain. (The message you have entered is too short. Please lengthen your message to at least 25 characters.)
 
  #30  
Old 01-16-19, 05:17 PM
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Smoke testing gives nothing about stack temperature, CO PPM, draft......
All very important when setting up a burner.
At the least it appears your hitting the target wall with flame. Which is why I suggested you appear overfired.
 
  #31  
Old 01-16-19, 05:25 PM
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please explain. Wouldn't overfire effect smoke test results? (The message you have entered is too short. Please lengthen your message to at least 25 characters.)
 
  #32  
Old 01-16-19, 05:28 PM
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ok (The message you have entered is too short. Please lengthen your message to at least 25 characters.) (This forum requires that you wait 180 seconds between posts. Please try again in 129 seconds.)
 
  #33  
Old 01-16-19, 05:34 PM
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Not necessarily, no.
Smoke is far from the only piece of data needed to start screwing around with the air band.
You also seem to be using the speed of which the house is heated to gauge combustion. Your last burner tech may have very well adjusted it properly. But you said it was running too lean because of how quickly the space temperature was increased.
 
  #34  
Old 01-18-19, 09:00 PM
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No one has suggested smoke tests should be the universal benchmark for oil burners. It is a simple basic adjustment. Yes, it can impact other things, but usually that is not significant.

No post so far has suggested factoring in the lunar state, barometric pressure or whether the cat is in or out. Lets see how far this thread goes.
 
  #35  
Old 01-18-19, 09:36 PM
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Actually yes it is significant.
Who wants to clean a heat exchanger multiple times per season because of sooting from poor combustion. Or burn up a target wall from overfiring.
DIY is fine. This is a diy site. But that doesnít mean things should be done poorly or improperly.
This isnít really any sort of discussion. Setting a burner of any fuel requires instrumentation. Not doing so puts a theoretical blindfold over those doing the work.
Ever see a house fill with soot from a misfired oil burner? To the point the insurance company had to send a fire remediation team out for cleanup? I have, to a point the walls were black, and every horizontal surface was covered in soot.

From Beckett themselves-

https://www.beckettcorp.com/support/...er-adjustment/
 
  #36  
Old 01-19-19, 09:43 AM
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A “0” smoke test reading is no smoke or sooth. That is not improper or suggest poorly done.

Maybe roughneck77 can explain how a setting air for zero smoke results in sooth filled boiler and house.

Also, most professionals around here “eye-ball” the flame and do not use instruments.

The roughnexk77 Beckett link is for setting up a whole installation, not simple adjustment of one thing on existing system.
 
  #37  
Old 01-19-19, 10:27 AM
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If the folks around your area eyeball only, they are not professionals. And cannot tell you how efficiency, or inefficiency, your furnace is operating.

Sure, I can tell you one way of many zero smoke can lead to sooting. You set zero smoke. All is well and you walk away. But because you did no further measurements you didnít realize draft is insufficient. The retention head and nozzle overheat. Deposits begin to be left on both, and the retention head warps from overheating. Combustion quickly declines and sooting begins.
If you need personal experiences I have many. But two that stand out-

Oil company came out and cleaned boiler. Never did combustion test. Approximately 4 days later the boiler clogged with soot to the point that fire was shooting out the inspection port. The blast tube and retention head were warped. Nozzle jet black. Cause was sludge and water in fuel, resulting in poor, unstable combustion.

Second was a furnace that had a full cleaning and PM done. Draft was not tested. The chimney liner had started to degrade and crumble, but visually wasnít noticeable. Flame looked decent but the draft was horrible. The retention head warped until the vains were almost compleatly shut. The flame was severely starved and the upper part of the heat exchanger clogged with soot. Smoke was discharged out of the furnace and covered everything in the basement in soot. Homeowner made an insurance claim for cleanup.

Third was a gas furnace and doesnít really matter in this case. But it was relatively new and was serviced on a semi-annual basis. Heat exchanger has a problem and furnace was discharging large amounts of CO out the exhaust. Which was getting pulled back into the basement due to low building pressure and leaky basement windows. High levels of CO in basement causing headaches and nausea to homeowners. Unfortunately they had over the counter CO detectors (I think from Loweís) that never went off.

As far as the link, beginning of season service should be done like a new startup. You donít know whatís changed.
 
  #38  
Old 01-19-19, 02:46 PM
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.005 to .008" wtr over fire and -.008 to -.01 barometric damper with barometric damper totally sealed. (otherwise air was leaking in around the barometric damper door opening even with weight set, some air got in and i was getting .005 to .0008)

This is with fire eye set. im still waiting for the smoke spot strips to get here.

Again: Reading over the manufacturer's (beckett) "Set combustion with instruments" It says:
Adjust the air shutter/band until a trace of
smoke is achieved.
Increase the air to reduce the CO by 1.5 to 2 percentage points.
Recheck smoke level. It should be Zero

The air handler (carrier) "Combustion Check" says:
"1. A test kit to measure smoke, stack draft, over-fire draft, oil pump pressure, CO2, and stack temperatures MUST be used in order to obtain proper air band setting. Although all of the above measurements are required for optimum setup and efficiency data, the most important readings that must be taken are smoke number, over-fire draft, stack draft, and pump pressure.
2. The proper smoke number has been established by engineer-
ing tests to be between 0 and 1. This degree of smoke emission
is commonly referred to as a"trace′′of smoke. It is recom-
mended to use a Bacharach true spot smoke test set or
equivalent."
 
  #39  
Old 01-19-19, 03:35 PM
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You are looking for an overfire draft of -.01 and a breech draft(in smoke pipe) of -.03 or .04. These are negative readings. You should be able to put the back of your hand in front of your observation door and not feel any heat if you have proper draft.

That barometric damper works automatically and should not be sealed. If you have a high draft chimney the door automatically adjusts for that keeping the breech draft steady. From the damper to the boiler is called controlled draft which is important to the proper combustion readings.

Too much draft you can pull the fire from the nozzle and too little will overheat the chamber and give you backdraft which doesn't allow for the combustion by-products to go up the chimney.

Your temp gauge will also tell you if you are over firing or if your air setting might be open too much or not enough. Too much will lower the temp of the fire and exhaust.

Smoke is obviously important as has been discussed.

Roughneck is spot on with his advise in my opinion and for what it's worth I agree with him and would follow his suggestions.

If you set your temp, draft and smoke, the efficiency will take of itself. It is just the end result of all your other settings and in my opinion it's the least important tool of the 4 because it's only a number for the curious. If everything is set properly your efficiency is what it is.

I put very little stock in CO2 readings because like everything else if you know what you're doing they can be fudged.
 
  #40  
Old 01-19-19, 05:24 PM
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carrier label says "The draft regulator should be adjusted after furnace has been firing for at least 5 minutes, and set between -0.02 and -0.035 in. wc."

also

"OVER-FIRE DRAFT MAXIMUM 0.020"

I can't get -0.02 at the regulator. The best it will do is -0.005 to -0.008, however with it sealed it gets -0.008 to -0.01 which is closer. I plan on monitoring this and if the atmospheric variations do not cause it to go below -0.035 all is good? Or will the atmospheric variations cause my air/fuel ratio to alter, which means better to leave it unsealed even if that means a higher off spec number?

tks,
pa
 
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