Oil Burner Air Adjustment On Boiler Using Only a Smoke Tester

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  #1  
Old 10-06-08, 05:42 PM
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Oil Burner Air Adjustment On Boiler Using Only a Smoke Tester

Greetings.

As I indicated last Spring, I intended to obtain and install a Beckett oil burner (model AF) in my 1970s era American Standard boiler. I successfully accomplished that over the summer. The burner head and nozzle were properly sized. The boiler was cleaned and its combustion chamber was relined. Now it is time to make the final adjustments as cold weather approaches. Unfortunately I do not have a combustion analyzer that has an accurate oxygen sensor. Only the temperature and smoke spot features work properly so I can't measure efficiency. Here is the procedure I used to adjust the burner. I would like to know if this was adequate.

As I understand it, proper combustion in an oil burner is a balance between getting complete combustion of the oil but without pulling excess air through the system. Too little air causes inefficient burning of the oil, resulting in carbon monoxide, and sooting problems with unburned oil being sent out the chimney wasting money . Too much air on the other hand results in better combustion but with a loss of efficiency as the hot gases are drawn through the heat exchange too fast, preventing the efficient transfer of heat between the hot gases and the boiler. This results in wasted heat energy going out the chimney, another waste of money.

With that in mind, here is what I did to adjust my burner with the tools I had. As I said before, the smoke tester in my old Honeywell analyzer still works so that is what I used. I started with an initial burner air setting based upon the look of the flame and took a smoke measurement. My inexperienced eye was not too good. I measured a smoke spot number 4. I added some more air and tried again. This time I got a reading of 2. I continued adding more air and testing and ultimately got zero smoke.

I then repeatedly reduced the air in very small amounts and tested until I just got a hint of smoke; a smoke spot reading of less than 1. I then added a very small amount of air and took my final reading and there was zero smoke. I left it at that. The burner ignites quickly and burns smoothly. I did a smoke spot test a few days later and still got zero smoke.

Based upon my limited understanding, it would seem that I have reached the optimal air to fuel mixture. Combustion is complete as no smoke is being created with only a minimal amount of excess air being present. Does this sound reasonable to you pros? Is there something serious I have overlooked that going to come back and bite me in the future because of the procedure I used?

Thanks, Bruce
 
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Old 10-06-08, 06:10 PM
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Not being a pro, but being somewhat experienced, what can happen at this setting is to run into a "bad air day." When this occurs the burner can soot a little. The issue with this is that the soot coats the heat exchanger and reduces the efficiency.

This loss in efficiency lasts until the heat exchanger is cleaned.

A bad air day happens with higher ambient temperature and/or lower barometric pressure. These weather conditions reduce the available O2 and can cause the burner to run rich (soot).

OTOH, this is the worst case.

When a CO2 or O2 reading is available, the burner is set for 0 smoke and the CO2/O2 reading is noted. Then the air shutter is opened until the CO2 decreases by a percent (or a percent and half).

This allows a margin for bad air days.

However, it is best to note the intake air temperature and barometric pressure. And account for that at this time. I know, this can be getting too involved. However, if the burner is setup on a "bad air day", then this compensation isn't required.

And if the burner is set up on a "real good air day", then the compensation needs to be greater.

Al.
 
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Old 10-06-08, 06:31 PM
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Will readjust on "Bad Air Day"

This is good information that makes sense. What I will do is this. Wait for the next rainy day we have when the barometric pressure is low and when it is relatively warm outside. At that point the air density will definitely be lower than at any time likely to be experienced during the winter. I will repeat the smoke tests and find the optimum position on this "Bad Air Day". I should then be in good shape for the majority of the days during the winter when the air density should be much greater due to the colder winter temperatures.

Thanks for the info!
Bruce
 
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Old 10-06-08, 07:04 PM
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Red face

To me this is the way to go.

From limited experience soot just kills the efficency. So a little excess air to prevent soot pays off. I do know that this year I'm shooting for less then 0 smoke on decent air.

Al.
 
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Old 10-06-08, 08:06 PM
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What OB is talking about is sometimes called 'insurance air', and it's not so much for 'bad air days' as it is for dealing with COLD OIL. If your tank is in a heated space, this won't be quite as important, but if the tank is outdoors, and not underground, the oil will get a LOT colder as the season progresses.

Cold oil will produce LARGER DROPLETS at the nozzle, and these droplets may not burn completely, causing smoke and soot.

Adding 'insurance air' allows the burner to run on the lean side during the fall and late spring but insures that there is adequate air for proper combustion when the oil is cold.

One thing that will help a boiler maintain proper combustion throughout the heating season is running a higher fuel pressure and downsizing the nozzle to get back to the desired 'firing rate'. Nozzles are spec'd at 100 PSI. If you run 140 PSI, you will naturally get more oil through it, but the spray will be much finer. There are charts available on the web that show how much a given nozzle will spray at a given pressure.

For example: (example ONLY! I don't have the chart in front of me...) Let's say that you want to fire at 1.00 GPH . At 100 PSI, you would use a 1.00 nozzle. At 140 PSI you might have to go to a 0.85 nozzle ...

Bruce, what are you firing at ?
 
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Old 10-06-08, 11:45 PM
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Oil Tank is Inside

My oil tank is in a heated area which never gets below 60 degrees so oil temperature should not be a problem during the winter.

The Beckett burner has a .85 nozzle installed and is operating at 100 psi. I have a couple of .75 nozzles on hand to try if I ever boost the oil pressure but for the time being. I want to leave the pump pressure at the factory set 100 psi and see how things go with that for a couple of months.
 
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Old 10-07-08, 06:39 AM
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I think I clicked on something I shouldn't have. The little face icon at the top of my previous post shouldn't be there, lol. Looks like he's frowning... Which isn't the case for my reply.

Al.
 
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Old 10-07-08, 07:00 AM
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Just as important is the draft. As the draft changes it will pull more air through the burner air gate and cause the CO2 to go down and may cause hard starts. You need an overfire draft reading. If the draft ever exceeds -.04" w.c. your flame will bounce on and off the head and create soot. When the burner is adjusted in warmer temps shoot for a low draft. As the outdoor temp drops the average internal chimney temperature increases and so does the draft. This causes more air to be pulled through the chimney and affects the CO2. There is your excess air but it may be too much excess air. The burner should be adjusted to the proper CO2 which is normally around 12% today. Adding too much air will drop the CO2 and as the weather changes it will drop it even more making the system even less efficient. Pay someone to set up the oil burner.
 
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Old 10-07-08, 09:52 AM
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Good point about the draft. Bruce, was it you that posted a picture of the open door on the boiler? It showed some firebrick residing in the heat exchanger area? That is done to reduce the draft. I did the same with the boiler here. Last year I used bits of metal, but purchased a fire brick this past summer.

Sliced it up into smaller rectangles to more easily fit into the required areas. The boss hasn't requested heat yet so I haven't finished setting up the burner/boiler for the winter. Although it is getting chilly outside.

For draft I use the Dwyer 460 gauge. Inexpensive and easy to use.

http://www.dwyer-inst.com/Products/P...m?Group_ID=173

{edit: oops, first link I posted was broken, this one should work}

Al.
 
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Old 10-07-08, 08:49 PM
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Thanks

I did not post a picture of my boiler. Old Boiler must have been looking at a different post.

I probably should have mentioned that I have one of those little pocket-sized Draft-Rite gauges. The firebox reading was between .02 and .03 so it does not look like I am pulling excess air through the system.

In response to the comment "Pay someone to set up the oil burner."
OUCH….. that sure touched a sensitive nerve. I thought this web site was called DoItYourself.com. That's why I am here. I am looking for some helpful advise on how to do a job myself, not pay someone else to do it for me. Before I pay someone else to do this job, I'll pay Patriot Supply the $155 they want for a new oxygen sensor for my analyzer. If I can read about it, buy tools to do it and get good advise from helpful, knowledgeable people, I will do the job myself. Paying someone else to do a job I am capable of learning how to do is the last thing I want to hear, ….especially on a Do-It-Yourself web site.

Moderator, feel free to close this thread. Thanks to all for the useful input.
 
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Old 10-08-08, 03:18 PM
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Bruce, some jobs simply are over the abilities of a DIYer. I spent more than thirty years in the design, installation and operation of industrial and commercial sized boilers. We had our own combustion analyzers and there were times that we STILL had to call in the specialists.

There are so many different adjustments on oil burners that unless one works with them every day you simply cannot know what making one adjustment might do to a different parameter. Just because you adjust your air shutter for a "trace" of smoke does NOT mean the burner is properly set up for maximum efficiency. Even if you measure a low oxygen content in the flue gases does not mean that you might not also have low carbon dioxide, high carbon monoxide and high oxides of nitrogen. You MUST have the proper tools AND they need to be properly calibrated. You must know how nozzle positing in relation to turbulator and flame retention head interact with different air shutter settings.

Maybe you can do all these things and maybe you can't, maybe you have no problem in purchasing a $2,000 combustion analyzer and spending several hundred dollars each and every year in maintaining it and having the calibration checked. For probably 99.9% of the populace this expense would be insane to keep from paying a professional $150 a year to ensure their oil burner was in top form.

Please don't think that the ONLY purpose of this forum is to tell people how to Do-It-Yourself. One of the primary rules of DIY is to understand when the most important tool you can own is the checkbook and that sometimes the use of that tool is the best way to do a job.
 
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Old 10-08-08, 05:53 PM
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Bruce, relax... we have NO WAY of knowing your 'limitations'.
 
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Old 10-09-08, 05:18 PM
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Un-f-ing believable, there is no way a 2K combustion analyzer is required to set up an oil burner. Oh, some may THINK that, but how can it be true when they have been set up by 'eye' for over a century (that is sure to arouse some brain cells!).

Oh, wait, this is the "new-era." This equipment must be used!

Then again, oh wait, a NOX measurement, right. LOL!

And to state: "Pay some one to do it." Again, RIGHT!. I tried and they walked away. I tried again and they didn't show up. I tried again and they walked.

Gee, they did send a sales guy to try and talk me into a aluminum pinboiler. Great sales job when the house is full of cast iron rad's, cast-iron BB, and a slab.

OK, let's say I did have that "new aluminum pin-boiler" installed. Would it have been truely cleaned?? And set up with CO, CO2, smoke, NOX, and draft measurements? Well, would it have been?

Hell, the past "tech's" left card after card stating 84-85% efficiency!! Which if you go back and find my threads was laughed at by all those here.

How about the flue damper that was installed by a "professional." Yep, have the receipt, and have the proof that it was incorrectly wired. Putting everyone in this house in danger of CO poisoning. IT WAS WIRED TO OPEN AT THE SAME TIME THE BURNER WAS FIRED UP! If it didn't open the flue vented into the house! There was NO INTERLOCK.

Was over a friends house recently and the topic of boilers (and cost of heat) came up. I did not find ANY access port on the flue. YET, IT HAD BEEN SERVICED FOR YEARS! I was afraid to ask if we could open it. Vertical flue, figured it was a pin job. Does anyone here want to bet that that boiler is at least half plugged?

Sorry Pro's, either do the job or keep out of the DIY forum. The only reason I am here is because the pro's wouldn't do the job.

Just look at my past threads.

And the Pro's wonder why home-owners want to watch what they do. And why they feel as though they are being ripped-off. A "tune-up" isn't a filter change and a "look-see."

Oil has always been cheap, so "cheap" work has gone along with it. This is now coming back to bite the hand that fed oil. Oil is no longer "cheap." So why would the public put up with "cheap" service?

Hell, the "new" Carlin 100CRD I recently obtained has a intermittent control on it (R8184G-4009). This is a step BACKWARDS from the 50 year old stack controller with interrupted ignition that is now in place.

Why is this control even available?? Stupid, shot in the foot stupid.

In the past twenty years (at least!) every control should have had a delayed oil valve and interrupted ignition on it. No if's-and's-or-but's.

Al.
 
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Old 10-09-08, 08:47 PM
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I am sorry you feel so negative towards the pro's. You are taking your frustrations out on the wrong people as the pro's would have done the job correctly. The problem is you do not know the pro's from the hacks from the Ok tech's. As in every industry there are better than average people, average people and less that average people. I don't know your situation so do not take this the wrong way but normally the less expensive the rate the less knowledge the contractor has, or the more corners are cut. There has to be a reason he is a lot cheaper. This is not true all the time but most of the time. To obtain knowledge costs money. The distributors offer manufacturer training schools and have a hard time filling the classes. The same guys attend all the time. When you ask them where most of their tech problem calls come from they tell you the guys that never show up for the schools. There are two benefits to schools. 1) The tech actually learns about the product. 2) even more important is they have a name and a face of someone from the factory they can call when they do have a question or problem.
Again not all tech's are created equal. Some tech's have a job and some have a career.
When I started as a service manager I had 28 tech's. Out of the 28 I had 2 really good tech's and 2 really bad tech's. The balance were slightly below average to slightly above average. After a year and a half of in house training I had 6 really good tech's about 4 just below average tech's and the balance was just above average. Education is a wonderful thing. Our call-backs went from 10% to 1.5% in that time period. The rest of that story is we were the most expensive guys in town, and also the most busy. Normally the higher dollar rate was cheaper as less parts were changed un-necessarily. Everything was troubleshot and not guessed at. The use of test equipment is needed to become a good tech.
In today’s market of higher efficiency equipment and brighter fires we must use test equipment. The equipment must be used any time anything is done to a gas train or to the oil side of the oil burner even as small as a nozzle or fuel filter change.
 
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Old 10-10-08, 05:06 AM
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I too have felt Al's frustration...

I've always been one to study and learn everything I can about everything I can. I'm not one to sit in front of the TV with a can of beer while someone else maintains my life for me. BUT I do drink my fair share of beer...

Long story short, a few years ago I had trouble with my oil burner, checked this, that and the other thing, couldn't pin down the problem. Getting older and less flexible I figured it was time to accept my own limitations and call a pro in to service my system ... I opened the yellow book... called EVERY oil service company in there, perhaps 20. I don't remember the exact numbers, but of all the messages that I left on machines, probably only one or two callbacks resulted. They weren't interested. The ones that I did get a human answer, maybe 5 ... a couple took my number and promised to get back ... never did... a couple wouldn't come out because I didn't buy oil from them... finally one guy said he would send his 'best tech' over... the guy was four hours late... looked things over, adjusted the fuel pressure, adjusted the air band by eye, said it all looked fine... I said, aren't ya gonna check the smoke ? He said he didn't have a smoke gun ... his bill wasn't outrageous, so I just paid him to leave.

"ARGGHHHHH, That's a SHARP FLAME!"

That's when I purchased my own test equipment and decided to learn all I could about that beast.

The sad fact to all this is that it's not only oil service companies, it's EVERY SINGLE SERVICE COMPANY ! and EVERY SINGLE CONTRACTING COMPANY ... try getting a roofer ... or a plumber ... or _____________.

rbeck, please expand your service area into central NJ !
 
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Old 10-10-08, 09:25 PM
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I understand the frustration also. When I had a new furnace installed the installers never checked the draft loss across the heat exchanger, never checked the temperature rise across the heat exchanger, never checked the gas flow to the unit and never did any kind of stack gas analysis. When I asked them about these things the answer was that these were done at the factory and not necessary after installation. They also told me they could tell about the airflow through the unit by how it sounded. Of course they also installed a furnace 50% larger than contracted for under orders from their boss. (That I did make them change.)

This company also included as part of the installation a free check-up after one year. The technician that came out was a very nice man who welcomed me watching him work. Over the course of the hour he learned I was no dummy when it came to furnaces and he stated that I could easily do what he was doing. When he had finished I asked him if was going to check the gas pressures on high and low fire and he sheepishly stated that he wasn't because his digital manometer had a broken battery wire. He then said that if I had a soldering iron he might be able to fix it.

When he saw my Weller temperature-controlled soldering iron he knew I was no beginner when it came to working on electronic parts either. He asked me to solder the wires. Anyway, after getting the meter working (of course I have no idea of the state of calibration) he checked the gas pressures and found out the unit had been overfiring since installation, assuming his manometer was in calibration.

This was no fly-by-night company either; they had been in business for over eighty years and had an excellent reputation.
 
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Old 10-11-08, 08:42 AM
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Originally Posted by OldBoiler View Post
Good point about the draft. Bruce, was it you that posted a picture of the open door on the boiler? It showed some firebrick residing in the heat exchanger area? That is done to reduce the draft. I did the same with the boiler here. Last year I used bits of metal, but purchased a fire brick this past summer.

Al.
Hi OB



That was me who posted the pictures. I put a AFG Beckett Burner on this summer. Also was going to install a new oil tank but that is on hold to spring. How much did the fire bricks effect your draft?

I ended up with my draft -02 creeping almost halfway towards -03. I am wondering what it will go to when the cold weather comes. I have no more adjustment with the damper. If I get more fire brick do you think it will help me have some more adjustment. There is only a few pieces in there now.

Can you get fire brick at HD or Lowes?



This is the first year I might go without a service contract. After learning the basics and looking at my boiler and the service tags I now know how bad a job my company was doing. My company is the largest and probably the most expensive in the area. I would actually love to pay the service contract and know my boiler was properly cleaned and had a real efficiency test done. I would like to know if my boiler breaks down I will get a top notch tech to come and fix it but the odds are I would not. So far I have not paid it.

So I guess that means I most likely will be posting more questions for the thoughtful pros and homeowners here .
 
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Old 10-11-08, 12:32 PM
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Yes, I do recall the Beckett going in to replace the New Arco Flame (the burner that never dies, lol). I have a Carlin 100 CRD going in for this Winter. Waiting for it to get cold enough to need the boiler first. Do a final checkout & setup on the ArcoFlame then pull it for standby duty (I hate to see it go ).

I haven't used the firebrick yet. However, the pieces of metal that was installed last Winter reduced the OF draft about .005" WC (from about -.025 to about -.020). More importantly it reduced the stack temperature a good 60 deg F. That surprised me as I didn't expect it to drop that much. Most likely had to do with the added turbulance causing more heat to be extracted.

I got the firebrick at P-S, VESUVIUS FFBD3000, it is the high density stuff. I haven't seen it at a box store. Could try a fireplace/firestove type of shop. They may have it. I know it did bump the shipping up, being as heavy as it is.

The Oakmont has the flue passages turned 90 deg to what the Arcoliner has. Basically the fins are vertical on horizontal cross pieces. This makes it easy to set the sliced up rectangles of brick into the flue passages.

Same here with the limit of the damper. It is fully counter balanced at the end of the setting. My understanding is that if required a second damper can be added.

Another trick is to add door seals. This reduces tramp air. The way I did it can't be done while the boiler is in use. It takes a few days to build up and let the seal cure. I think it took about a week before the seals were finished. Did both doors.

Where the door mets the boiler is a raised edge. Wire brush that clean, then put a bead of high temperature RTV (silicone sealer) on the raised edge. Cover it with some plastic wrap (kitchen food wrap) and gently close the door. No need to bolt the door tight, just closed is all that is required.

After a day or more the plastic wrap will peel off easily. Another bead can be placed on top of the previous one, re-covered and the door again closed. Keep doing this until the seal and door meet evenly.

The high temp RTV can be had from an auto store. The Ultra Copper is best for this job.

Al.
 
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Old 10-11-08, 01:22 PM
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Thanks for the tips. I will have to try to get some fire brick locally or maybe order it. That would be the easiest fix. Hopefully I will be fine the way it is and the cold will not change the draft to much. Just not sure.

I did read somewhere about a second damper, glad to here you confirm that.

If I have to I will try the seals. Just do not really want to pull doors off at this time. Also have tankless coil so there would be no hot water for the few days.

I bought a second AFG on ebay for parts that is the same as the one I put on my boiler. Hopefully it works, looks real nice. I think I paid $75 total for it.


I just recycled the old burner last weekend. Felt funny getting rid of it. The new one does burn so much cleaner. I do not know if it is the cleancut pump or what but the old soot I could not get to in tight areas is peeling off like old paint chips.

Thanks (more questions coming)
 
  #20  
Old 10-11-08, 07:27 PM
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I have had similar experiences with 'Pros'. I called several oil burner service companies, specifically asked them to make sure they brought a combustion analyzer and smoke tester. None of them did. Excuses like "oh it's in the other truck" or "these old burners can be done by eye", etc. I decided to do the same as NJ Trooper and read up on the subject, bought my own equipment and learned how to use it (yes, it cost me almost $1,000). After feeling comfortable using the tools, I replaced the original burner in the (1975 American Standard) boiler with a new Beckett AFM and have been very pleased with the results. I probably saved at least $500 right there and in the 3 years since, doing my own boiler cleaning and tune ups, the instrument and smoke tester have paid for themselves.
 
  #21  
Old 10-11-08, 08:58 PM
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My experience with a "pro" was last year... Had my Weil-McLain P-68 Boiler with Beckett AF Burner serviced in the early fall (still warm out) to avoid the cold weather rush. He cleaned out the soot, put some new parts on the burner and adjusted the burner BY SIGHT ONLY(no smoke out the chimney). In my ignorance, I just thought he was a skilled old-school tech and since it was clean and no smoke, I thought I was ready for winter...

Come winter when the first real cold snap hits and the heat pump no longers works effectively, I turn on the OIL HEAT. An hour goes by.... NO HEAT. Hmmm...

I go check it and have to hit the burner reset. The fan starts but I get no ignition. Reset pops... Hmmmm, this is terrible timing I think to myself... I call the PRO and get the answering service... They say he is very busy and will call me back sometime tomorrow. What about my heat tonight, I ask, especially since I just had it SERVICED? Too bad, so sad...

Long story short, I had a CRASH COURSE in Oil-fired Boiler operation and adjustment. My logic told me it had something to do with AIR FLOW due to the heavier, cold air and also the colder fuel. So I worked on that and eventually got IGNITION! I then fine tuned the flame the best I could BY SIGHT from the access hole and also set it to almost zero smoke outside coming from the chimney. It lasted ALL WINTER with no problems and I just opened up the heat exchanger top cover and found only minor soot deposits, mainly in the most rear exchanger. I was pretty proud of myself...

But this year, after learning more, I have a tech with a Backarach test kit coming out to set it up. It was NOT EASY finding one with such a test kit... Most told me that it was not needed. I'll see how close my BY SIGHT settings were... plus I am going to watch him like a hawk to learn all I can...

Just thought I would share my PRO story...

Rmpl
 
  #22  
Old 10-20-08, 02:20 PM
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What should be measured? (and) Why not EFI?

This thread has been very interesting. There are always many horror stories. But one common theme is the service person who does things by eye, or with only one or two measurements.

First, can someone provide a list of "everything" that could or should be measured (with normal ranges) to ensure correct adjustment? I don't mean science fair measurements, but those that really are important but that typically get overlooked.

Secondly, why don't we have, in this day and age, EFI for our oil burners? My god, throw in a couple of sensors and an ECU with decent mapping and all of this measurement concern, "insurance air" and the like would go away for good. I envision a true closed-loop system, with an oxygen sensor.

No one questions the value of EFI systems in our automobiles, and they are pretty easy to maintain - they even tell you what's wrong. Would you want your car that someone tuned up by 'how it sounded' or the appearance of the exhaust?
 
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Old 10-20-08, 02:44 PM
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Things that should be measured (in no particular order) on oil burners would include the net stack temperature (temperature of exhaust gases minus the temperature of the incoming combustion air), the percentage of carbon dioxide in the stack gases, the percentage of oxygen in the stack gases, the percentage of carbon monoxide in the stack gases, the percentage of nitrogen oxides in the stack gases and the smoke number of the stack gases by the Shell-Bacharach test method.

While a computerized adjusting and control system sounds like a good idea the actual application would be far to expensive, intricate and subject to failure to make it cost effective or practical. Even on commercial and industrial equipment the controls rarely go beyond a fairly simple oxygen trim system that adjusts the combustion air to maintain a fixed oxygen content on the flue gases. These oxygen trim systems are NOT inexpensive and they require a fair amount of maintenance. They can be justified because the systems on which they are fitted often burn more fuel in a day than a residential unit will burn in a year. The last place I worked before retirement could easily burn more than 15,000 gallons of fuel oil in a 24 hour period.
 
  #24  
Old 10-20-08, 03:10 PM
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Thanks for your reply.

Can you provide normal ranges or baselines for those measurements (CO2,CO, O2, etc.)? That would be very helpful.

I understand your point about the automatic controls. I will say up front that I don't know anywhare near as much about all this as you and the other professionals do. I do remember the same things said about automotive fuel injection systems as they were introduced.

As far as I am concerned, any time you are talking about setting up a system to reasonably handle average conditions, there is an opportunity for real-time correction via feedback mechanisms. With the price of oil, control technologies can become cost-effective. It started happening with automobiles about 20 years ago and nowadays it is the norm. Try to find a mechanic who knows how to properly set up a carburator!

With millions of homes with furnaces, there is a large potential marketplace. Again, I understand your point, and I am in no way neglecting the real-world experience you accumulated over many years. I am simply wondering if the time has come for more precise operation through active feedback controls.
 
  #25  
Old 10-20-08, 03:19 PM
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Originally Posted by plym49 View Post
This thread has been very interesting. There are always many horror stories. But one common theme is the service person who does things by eye, or with only one or two measurements.

First, can someone provide a list of "everything" that could or should be measured (with normal ranges) to ensure correct adjustment? I don't mean science fair measurements, but those that really are important but that typically get overlooked.

Secondly, why don't we have, in this day and age, EFI for our oil burners? My god, throw in a couple of sensors and an ECU with decent mapping and all of this measurement concern, "insurance air" and the like would go away for good. I envision a true closed-loop system, with an oxygen sensor.

No one questions the value of EFI systems in our automobiles, and they are pretty easy to maintain - they even tell you what's wrong. Would you want your car that someone tuned up by 'how it sounded' or the appearance of the exhaust?
For a residential oil burner these are the measurements that should be taken. And used to adjust the system:

Oil pump pressure
Flue CO2
Flue Smoke
Flue Temperature
Flue Draft
Overfire Draft

A CO reading would be nice as it would let the tech know if the flame is impinging someplace. Which results in an incomplete burn.

There are systems being developed that use a Cad cell to 'look' at the fire. However, it is being used as an alert that something is wrong. Not a self-adjustment feature.

For some reason it has been very slow for the heating industry to try new things. They seem to like the old ways.

As for 'EFI', I have something up my sleeve that I've been working on. Biggest problem is keeping the SO from finding out

Al.
 
  #26  
Old 10-20-08, 03:55 PM
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Believe me, it is being worked on and developed as we speak. Look across the ocean...

I believe the Buderus GB125 has an 'EGR' system to reduce NOx emmisions already.

The quality of the fuel oil has to be improved dramatically for an injector to be reliable. We change nozzles yearly... because they will clog at the worst time ... cheap insurance. Injectors are too expensive to be changed yearly.

I can't wait to hear what Al has up his sleeve... he DOES have an O2 sensor on his dinosaur already!
 
  #27  
Old 10-20-08, 04:02 PM
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Can you provide normal ranges or baselines for those measurements (CO2,CO, O2, etc.)? That would be very helpful.
Unfortunately I can't but I'm sure some of the other people can. My experience is with large equipment and quite honestly the basic design of the burner along with its specific application have a lot to do with the actual numbers that one will get via combustion analysis. I can tell you that with some of the large burners the CO2 will be 12% or more with as little as 3% (sometimes as low as 2%) O2. CO is always to be as low as possible but sometimes in order to get it to zero the O2 goes high and the CO2 will also drop so you see it is often a battle of averages rather than being able to get the ultimate reading on any one gas.

Sulfur Dioxide (SO2) is another pollutant gas that can be formed from combustion of fuels with sulfur content. Nitrogen oxides (which contribute to photochemical smog) form at high combustion temperatures and are often controlled by injecting stack gases back into the combustion air supply at the burner.

Of course you also want as low a stack temperature as possible but at the same time you can't go too low or else you risk condensation in the stack or last gas pass of the boiler. This can also happen when firing a boiler at a lower rate.

Try to find a mechanic who knows how to properly set up a carburator!
Or even someone that can properly spell carburetor.

The controls on automobiles, including fuel injection are not a good analogy to burner controls on a boiler (or furnace) because with the automobile we are talking of many small and short-lived combustions per second and with the boiler it is one long period of continuous combustion. Automobiles use lower compression ratios and exhaust gas recirculation (EGR) to control nitrogen oxides and both of these methods decrease the ultimate power generated. High compression, which gives high combustion temperatures, are ideal for high efficiency in an internal combustion engine but unfortunately it also exponentially increases the production of nitrogen oxides. Flue gas recirculation, combined with specially designed burners and combustion chambers allow boilers in commercial and industrial sizes to achieve low NOx production but they do so by lowering flame temperatures and therefore lowering radiant heat production with a corresponding loss of overall efficiency.

And so it goes for just about all the parameters of combustion. Raise a "good" level but in the process also raise a "bad" level. Controlling all of these parameters (heck, even measuring them all) is quite a job. A controller for a home furnace or boiler would have to control fuel pressure, airflow (probably both a primary and secondary airflow), maybe an atomizing medium, burner position and probably more that I can't think of off the top of my head. It would take sensors and actuators along with a microprocessor and none of it would be cheap. Nor would it be inexpensive to keep in operation; and service...well, you would have to train a whole new generation of service people and yo know that wouldn't be cheap either.

So, while I do think that we could do better it is going to be a long time before any significantly improved systems become commonplace.
 
  #28  
Old 10-21-08, 07:30 AM
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Thanks for all of your comments and replies. Darn I mistyped carburetor. Oops.

We can debate the pros and cons of electronic feedback controls. It has to happen; it is inevitable just like it was for automoiles. Oops, automobiles.

My biggest concern right now is having a warm fuzzy that my service contract people are adjusting my units properly. Each one does it by 'eye' or by 'ear' and that kind of 1860s work just does not cut it any more.

There are not many adjustments these guys are willing or able to make. I doubt if things like oil pump pressure show up on their radar screen. They don't measure it and I doubt they'd know what to do about it.

What do they do? They change filters and nozzles, adjust electrodes and adjust the air. Replace flue pipes and tape the damper closed (seriously!) because I was complaining about a burnt smoky smell (nothing visible) in my furnace room. That's it.

So, since I am dealing with people who only color with a few Crayolas, what readings would be in the ballpark?

I *believe* that my primary unit is a Beckett burner with .8 nozzle, on a Peerless boiler (three sections), maybe rated 120 or 150,000 btu?

I understand that I should know a lot more, possibly fire these guys, etc. etc. That's why I'm here! First things first though: they come round on Thursday for season start-up and I'd like to be as knowledgeable about what to ask for as I can.

Oh yes, and this setup produces way too much soot. Completely occludes the flueways in one heating season. (See my other post.)
 

Last edited by plym49; 10-21-08 at 08:52 AM.
  #29  
Old 11-16-10, 07:31 PM
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Becket puff back

My Beckett AFG burner does not fire smooth some time, it fires with a puff back
then runs normal ,shuts down normal. I have called the one that installed it about 3 times for this condition, every time the electrode was adjusted, never really solved the problem.Will an oil delay valve solve this problem?
 
  #30  
Old 12-12-10, 05:17 PM
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Puff Back

Even though you can make that spark from the ignitor jump a 1 inch gap does not mean it will spark every time. You may be getting an intermittent spark. I have found this to be the case more than once. Replace the transformer and problem went away.

Get the right ignition transformer or solid state ignitor for you burner. If it is a Beckett get the Becket part etc...
 
  #31  
Old 12-13-12, 10:51 AM
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my opinion about oil burner adjustment

Hi. I consider many opinions and am realistic, and hope to help some of you expand your opinion of this subject.

1. I consider this a somewhat high risk doing it yourself job, potentially dangerous, but very rewarding.

2. Calling a "pro" will not guarantee a perfectly running system. Some guys don't know or care what they are doing even though they are getting paid.

3. I believe that even if you professionally set up your oil burner over time it will or may slip out of spec. For example the nozzle may not deliver the exact spray pattern after weeks of use, it could slightly clog??? sometimes dirt builds up around the air openings too, or as people expressed even the air changes according to the weather. So I think we should not get too precise about this subject.

4. if you diy you should definitely use a smoke measuring instrument, the kind you put a paper element into (about $120), pump the furnace exhaust through and then look at the stain on the paper.

Assuming you are comfortable with cleaning your system, changing a nozzle, and adjusting the air I suggest using the smoke tester to find a range of stains by varying the air opening. I would not recommend trying to get zero smoke, I think that is too lean. The tester shows a range (0 - 10)and at 2 or 3 it says you might only have to clean once a year, and at 1 it says should not build up much soot at all, and 4 it begins to warn. However I think 0 can lead to just too much air. However if you disagree that is ok. I'm just saying this is not rocket science like some people imply.

But it is dangerous I repeat, so if you are not sure of yourself don't try it.

Another big recommendation is to check your system a few times each year to see how your combustion is. Also when you have too much air going into your burner the flame gets kind of noisy, you are kind of turning it into a blow torch! Common sense should prevail. hope this helped somebody.

btw my air setting on my becket changes the paper stain with an air opening change from say 2 1/2 to 3 or 3 1/2. You can see for yourself that you are ok withing a pretty wide range. It is not like you need an adjustment of 2.15!

[EDITOR's NOTES - This post contains one man's OPINIONS. The FACT is that if you do not have the proper equipment to adjust a burner to MANUFACTURER's SPECIFICATION, you should not even attempt to do any adjustments on the burner. MODERN EQUIPMENT needs to be adjusted with MODERN EQUIPMENT, meaning PROPER COMBUSTION ANALYSIS TOOLS that allow you to measure and adjust either CO2 OR O2, CO, and SMOKE. No, it is not 'rocket science', but it IS COMBUSTION SCIENCE. -- NJT moderator]
 

Last edited by NJT; 12-13-12 at 03:43 PM.
  #32  
Old 12-13-12, 11:12 AM
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This is an old thread and I am closing it.

Any questions regarding oil burners and adjustments please start a new post.

Thanks.
 
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