Burner air setup using only flue gas analyzer

Reply

  #1  
Old 11-22-11, 09:27 AM
Member
Thread Starter
Join Date: Nov 2011
Location: Canada
Posts: 88
Received 0 Votes on 0 Posts
Burner air setup using only flue gas analyzer

I have a Fieldpiece SOX2 gas analyzer. I don't have a smoke spot tester or draft gauge. So, I set up without them? I set the draft regulator to 0.04" using the numbers stamped on the slide. I hope that gets me close enough.
I have a Riello Mectron 5M burner on a NTI boiler. I downfired from a 1.0 GPH to a 0.85 GPH nozzle. I added a bypass loop to protect from low return water temps and reduce condensation. Last year I installed a Honeywell AQ475A outdoor reset control.
The CO2 was set to 12.0% based on information in this thread:
http://www.doityourself.com/forum/bo...ml#post1799582
Here are my results:
Outdoor temp=32F Barometer=30.3 in Wind=10 mph
Start O2=6.5% Excess air=42.4% CO2=10.7% flue temp=309F
End O2=4.7% Excess air=27.0% CO2=12.0% flue temp=353F
Do these numbers seem efficient, reasonable and safe?
Any suggestions for improvement?
 
Sponsored Links
  #2  
Old 11-22-11, 05:36 PM
Member
Join Date: Oct 2011
Location: canada
Posts: 568
Received 0 Votes on 0 Posts
Did you adjust the turbulator on the burner to match the new nozzle? The lines start at 0 not 1.
 
  #3  
Old 11-22-11, 06:05 PM
rbeck's Avatar
Member
Join Date: Jul 2007
Location: Pennsylvania
Posts: 2,450
Received 2 Votes on 2 Posts
I have a bit of a problem with the -.04 draft. Riello does not like much draft. I would get it closer to 0 to -0.01. As the outside air gets colder the draft will increase and cause the boiler to soot up. You need a draft gauge to set up Riello's and pressure fired boilers.
 
  #4  
Old 11-22-11, 06:14 PM
Member
Thread Starter
Join Date: Nov 2011
Location: Canada
Posts: 88
Received 0 Votes on 0 Posts
Yep, did that. Set electrodes too. Gave burner and the boiler a good cleaning too.
 
  #5  
Old 11-22-11, 06:25 PM
Member
Thread Starter
Join Date: Nov 2011
Location: Canada
Posts: 88
Received 0 Votes on 0 Posts
I set to -.04 draft because that's the boiler spec for draft at the breech. I'll look around for a draft gauge. I guess that means the scale on the Field controls RC draft control is not accurate? The scale is marked with settings from .02" to .08
 
  #6  
Old 11-22-11, 06:35 PM
Member
Join Date: Oct 2011
Location: canada
Posts: 568
Received 0 Votes on 0 Posts
Originally Posted by rbeck View Post
I have a bit of a problem with the -.04 draft. Riello does not like much draft. I would get it closer to 0 to -0.01. As the outside air gets colder the draft will increase and cause the boiler to soot up. You need a draft gauge to set up Riello's and pressure fired boilers.
I agree the set up must be complete, first set proper over fire draft,and make sure draft regulator can maintain set over fire pressure. Then find where burner creates smoke and test for co2 maximum 12.5 at 0 to #1 smoke.Most technicians will then add air to get 11.5 c02 . Last check the base flue temperature as you don't want to have condensation at the top of your chimney.
 
  #7  
Old 11-22-11, 09:36 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 2 Votes on 2 Posts
you don't want to have condensation at the top of your chimney.
Having done a fair amount of roofing work in my time, I've seen the tops of quite a few chimneys... and they ain't purty... damage caused by condensation ...

Another winter variable is the temperature of the fuel oil... not so much a problem with underground tanks, but if the tank is outside, as that oil gets colder the combustion changes.

To answer your original question, YES, you should have a smoke spot gun... perhaps even before a draft gauge...
 
  #8  
Old 11-23-11, 06:57 AM
Member
Thread Starter
Join Date: Nov 2011
Location: Canada
Posts: 88
Received 0 Votes on 0 Posts
Tank inside, new liner. Flue temp is 353F
 
  #9  
Old 11-23-11, 07:29 AM
Member
Join Date: Oct 2011
Location: canada
Posts: 568
Received 0 Votes on 0 Posts
That flue temp. should be fine if taken at the base of the flue,if taken before the draft regulator it is a mini um temp. for a proper size flue. I must stress that a smoke tester is essential for proper set up of burner.
 
  #10  
Old 11-23-11, 04:08 PM
Member
Thread Starter
Join Date: Nov 2011
Location: Canada
Posts: 88
Received 0 Votes on 0 Posts
Thanks to all for the advice. I'll work on getting a smoke spot tester and draft gauge.
 
  #11  
Old 11-28-11, 06:00 AM
rbeck's Avatar
Member
Join Date: Jul 2007
Location: Pennsylvania
Posts: 2,450
Received 2 Votes on 2 Posts
I believe the -0.04 is a maximum setting. Again if it is left there during warmer months it will exceed -0.04" w.c. If it does it will cause sooting and soot is an insulator. Properly set up there should be nothing to clean out of the boiler on an annual basis other than a very light coating of white to grey dust if anything at all. Nothing dark grey to black.
 
  #12  
Old 11-30-11, 09:45 AM
Member
Thread Starter
Join Date: Nov 2011
Location: Canada
Posts: 88
Received 0 Votes on 0 Posts
Thanks rbeck,
I came across a deal on a new Dwyer Mark II draft gauge for $20. So when it arrives I will be setting the draft properly.
Now to find a deal on a smoke spot tester to go with my co2 meter and I will be all set.
It amazes me the number of local techs that still set burners by eye. My brother had a new boiler installed and there are no sample holes in the smoke pipe. He was told the burner was set at the factory so no adjustments were required. My brother even got an energy rebate based on the efficiency improvement of the new boiler. The tech filled in Draft, CO2, O2 results even though testing was not completed and then signed the form.
My sister has her boiler done annually and no sample holes there either. There was none in mine either and all were serviced/installed by different "reputable" companies employing licensed technicians.
I don't mean to knock burner technicians, I know most are honest and strive to get the most heat out of your gallons of oil. I'm just relating my personal experience in my local area.
If anyone knows of a deal on a smoke spot tester, please let me know.

Thanks to all of you on this site for taking the time to explain the importance of proper setup.
 
  #13  
Old 12-08-11, 11:31 AM
Member
Join Date: Oct 2011
Location: canada
Posts: 568
Received 0 Votes on 0 Posts
I was just reading your results where you went from a 1.0 to a0.85 nozzle and the stack temperature went from 309f to 353f when usually the temperature would be lower,you must have increased the over fire pressure which would pull the gases through the heat exchanger faster giving less time for the heat to absorb into the boiler water.Was there any other factors such as not adjusting the turbulator to suit the new nozzle.
 
  #14  
Old 12-09-11, 04:16 PM
Member
Thread Starter
Join Date: Nov 2011
Location: Canada
Posts: 88
Received 0 Votes on 0 Posts
I got my draft gauge today. Started out measuring -0.04 to -0.05 at breech and -0.03 to -0.04 over fire.
In order to set the draft regulator to get near 0.0 over fire I had to add a little bit of weight (3 u nails, lol) as I ran out of adjustment. I ended up with -0.02 at the breech.
I'm sure this is not the right thing to do but the extra weight gets the draft where it should be. The draft regulator is 3/4 open though. I'm afraid it will run out of control under some conditions.
What other method is there to reduce the draft so I can get the draft regulator into a good control range?
Any recommendations?
Riello Mectron 5 burner, 6" Field controls barometric draft control model R-C
 
  #15  
Old 12-09-11, 04:34 PM
Member
Thread Starter
Join Date: Nov 2011
Location: Canada
Posts: 88
Received 0 Votes on 0 Posts
The turbulator was properly adjusted for the 0.85 gpm nozzle. The low temp was probably because the were the as found readings, the result of the burner tech setting by eye with the 1 gpm nozzle. The boiler was coated with a gray flakey scale and white powdery ash at the last cleaning. There was quite a bit of this flakey debris in the bottom of the combustion chamber too. It was during that cleaning that I down sized the nozzle and took the new readings. I set the exhaust for 12.0% CO2 as I don't have a smoke spot tester yet, hope to have one soon. I had a look inside the other day while I had the burner out to change a bearing in the motor. Looks much better no scale or soot buildup. I took out quite a bit of air to get to 12.0% CO2 with the 0.85 gpm nozzle. I assume there was way too much air for the 1.0 gpm nozzle too. Will too much air will cause low exhaust temp and scale buildup.
Originally Posted by saves View Post
I was just reading your results where you went from a 1.0 to a0.85 nozzle and the stack temperature went from 309f to 353f when usually the temperature would be lower,you must have increased the over fire pressure which would pull the gases through the heat exchanger faster giving less time for the heat to absorb into the boiler water.Was there any other factors such as not adjusting the turbulator to suit the new nozzle.
 
  #16  
Old 12-11-11, 04:06 PM
Member
Join Date: Feb 2011
Location: US
Posts: 552
Received 0 Votes on 0 Posts
Hello Addicted,
There are two cures for exess draft as i understand it.
The easy way is to add a second draft regulator.
The problem with this method is it sucks a whole lot of heated air out of the cellar and, if the chimney is inside, it cools off the chimney to where is doesn't add much heat to the house.

Method #2 is to cut a slot into the flue pipe after the draft control and inset a a flat piece of metal into the flue pipe to decrease the draft. Called a Neutral Pressure Point Adjuster.
See page 10 here for details:
http://www.ecrinternational.com/secu...cument/942.pdf


As far as adding weight goes, my draft regulator has a very large nut on it.
I have the same exces draft issues. One of these days, we are going to try the #2 method for a cure. With an oil vent damper after all of it

Peter
 
  #17  
Old 12-11-11, 05:12 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 2 Votes on 2 Posts
a Neutral Pressure Point Adjuster.
There was a fellow here, last year I think, that did just that with good success. I think it was "Al" aka "Old_Boiler" ... maybe...
 
  #18  
Old 12-11-11, 05:30 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 2 Votes on 2 Posts
Hmmmm... Fig 11 on page 22 of this Pensotti manual looks a LOT like Fig 9 on page 12 of the Dunkirk manual. Wonder who is plagiarizing whom?

http://www.pensotti-pna.com/Blueline-r%20Manual.pdf

Well, it looks as though they ALL do it!

http://www.htproducts.com/literature/lp-115.pdf

I guess there's just so many ways to draw such a thing.
 

Last edited by NJT; 12-11-11 at 05:50 PM.
  #19  
Old 12-11-11, 05:42 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,489
Received 32 Votes on 24 Posts
A neutral pressure point slide is not uncommon on gas conversions but I've never heard of one being used on an oil-fired unit.
 
  #20  
Old 12-11-11, 06:04 PM
Member
Join Date: Feb 2011
Location: US
Posts: 552
Received 0 Votes on 0 Posts
Originally Posted by NJ Trooper View Post
Wonder who is plagiarizing whom?
Ifi was a betting man, i put the $$ on public domain.
Probably invented decades ago and became common use:

In the United States, all books and other works published before 1923 have expired copyrights and are in the public domain.In addition, works published before 1964 that did not have their copyrights renewed 28 years after first publication year also are in the public domain

Peter
 
  #21  
Old 12-11-11, 06:27 PM
Member
Thread Starter
Join Date: Nov 2011
Location: Canada
Posts: 88
Received 0 Votes on 0 Posts
I tried an experiment based on method #2 from PeterNH. I used a coffee can cut in half to partially block the outgoing side of the tee where the draft regulator is mounted. Pushing it into the pipe reduced the draft quite nicely. The draft regulator now runs between 1/4 to 1/2 open now at -0.01 over the fire draft instead of nearly wide open before.
The only concerning issue that I can see is when the burner first fires up the draft goes positive for a few seconds and gives a little puff out of the regulator. I have a CO alarm with a digital display on it mounted next to the furnace so I'll monitor it to ensure it is safe to leave the pipe partially blocked.
 
  #22  
Old 12-11-11, 08:51 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 2 Votes on 2 Posts
Ima, check the instructions carefully... I believe I read where the NPPA is supposed to install between the boiler and the draft regulator.... not after.

Which makes me question how this thing works to get the range back on the regulator.

Or did I read wrong?
 
  #23  
Old 12-11-11, 11:20 PM
Member
Join Date: Feb 2011
Location: US
Posts: 552
Received 0 Votes on 0 Posts
Addicted,
NJT is correct.
Here is some more info:
http://comfort-calc.net/Resister_Plate.html
Got my "wires crossed" earlier.
Sorry for the confusion:

Peter
 
  #24  
Old 12-12-11, 12:41 AM
Member
Thread Starter
Join Date: Nov 2011
Location: Canada
Posts: 88
Received 0 Votes on 0 Posts
Thanks for pointing that out. The instructions do read to install between the boiler and the draft regulator.
However, when I blocked the bottom of the tee I lost control of the draft again. So it would seem that the NPPA has to be downstream of the draft regulator.
Another thing I noticed is that with the burner off the draft regulator stays open controlling the draft at the breech to -0.02. When the burner starts pre-purge the regulator closes for a few seconds and when the burner fires, the draft goes positive to +0.03 then the draft regulator goes back to controlling to -0.02 at the breech.
 
  #25  
Old 12-12-11, 03:11 AM
Member
Join Date: Oct 2011
Location: canada
Posts: 568
Received 0 Votes on 0 Posts
Imaddicted2u , since we are sticking pieces of metal into the flow of the exhaust,just for curiosity sake cut a piece of sheet metal 4 inches wide by 8 inches long bend it to make a two sided ramp, place it directly behind the regulator door, drill a test hole for draft gage so you can measure the pressure in the pipe directly behind the regulator door,screw one end of the inserted metal and bend the metal toward the door until you achieve a reduced pressure of 0.01 to 0.02 difference from the pressure in the pipe down stream of the first test hole when burner is firing.When this is achieved reset the over fire pressure using the regulator door weight as normally done.You will find that it takes a higher negative pressure up to -0.08 flue draft to get the regulator door to open when burner is off, give a much more steady over fire pressure under excessive flue pressures such as on a windy day.I found it quit dramatic as i have an outside flue , when the pressure taken down stream of the regulator would pull the needle off the gage scale, the over fire pressure would stay within 0.01+ or - of it setting.
 
  #26  
Old 12-12-11, 10:10 AM
Member
Join Date: Mar 2010
Location: Canada
Posts: 19
Received 0 Votes on 0 Posts
The most important draft reading is over fire. The reason they give you a spec for draft at the breech is for a reference so you know the standard drop across the appliance. Set up your NPPA and draft regulator for a proper draft over fire and be done with it. Since you've down-fired the appliance make sure you check your chimney base temps (after the regulator) so you know it wont condense in the chimney. Minimum base temps would depend on the length, size and type of insulation for the chimney.
 
  #27  
Old 12-12-11, 04:18 PM
Member
Thread Starter
Join Date: Nov 2011
Location: Canada
Posts: 88
Received 0 Votes on 0 Posts
Thanks for all the advice. Hey saves, I did as you suggested and now with the burner off the regulator is running closed. I think what you meant is detailed in this patent that you posted in another thread.
CIPO - Patent - 2459368 - Drawings - 1/1
 
  #28  
Old 12-12-11, 06:45 PM
Member
Join Date: Oct 2011
Location: canada
Posts: 568
Received 0 Votes on 0 Posts
imaddicted2u: Did you also notice a 50f increase in flue base temperature, and the regulator door does not open as much to maintain set over fire pressure.
 
  #29  
Old 12-13-11, 05:40 PM
Member
Thread Starter
Join Date: Nov 2011
Location: Canada
Posts: 88
Received 0 Votes on 0 Posts
Flue base temp is up about 40 degrees. I could feel the difference just standing next to the pipe.
I think I will see savings from not sucking so much heat out of the basement between firings and from improved heat transfer during firings due to the reduced draft.
 
  #30  
Old 12-13-11, 06:13 PM
Member
Join Date: Feb 2011
Location: US
Posts: 552
Received 0 Votes on 0 Posts
Addicted,
Now that you have severly modified the draft and the flue temperatures are up.
Have you completely re-tuned the burner?
Air, co2, smoke, turbulator, etc.

Peter
 
  #31  
Old 12-13-11, 07:53 PM
Member
Thread Starter
Join Date: Nov 2011
Location: Canada
Posts: 88
Received 0 Votes on 0 Posts
PeterNH
Yep, but in reality the draft did not change because I reset the the overfire draft to get the same reading as prior to the modifications, nearly 0. I checked the temperature at the breech along with the CO2 and both were the same as prior to the draft mods. The temp at the flue base went up due to the draft regulator flowing less dilution air during operation because it is more closed than before the mods. Prior to the modification the draft regulator was always near wide open, even with the burner off. The turbulator was set to match the nozzle per the Riello spec when I changed the nozzle. I've never adjusted it with the burner running, should I? If so what do I look for?
Bill
 
  #32  
Old 12-13-11, 11:35 PM
Member
Join Date: Feb 2011
Location: US
Posts: 552
Received 0 Votes on 0 Posts
Addicted, Any chance you can post some pictures of the mods.
I'm curious as to exactly how you did it.
I'm really interested to have the oil boys - maybe try it.

As we are planning to try the "blade" mod before the drat control.

As far as the turbulator goes, no idea.


Peter
 
  #33  
Old 12-14-11, 07:16 AM
Member
Thread Starter
Join Date: Nov 2011
Location: Canada
Posts: 88
Received 0 Votes on 0 Posts
Here is a pic of the mod taken with the damper door removed.
Pictures by billhillier - Photobucket
 
  #34  
Old 12-14-11, 08:32 AM
Member
Join Date: Feb 2011
Location: US
Posts: 552
Received 0 Votes on 0 Posts
Thanks Addicted,
Intersting, very interesting.
And that does the job..
I'll see if the oi guys are game to try it..

Peter
 
  #35  
Old 12-14-11, 07:29 PM
Member
Join Date: Oct 2011
Location: canada
Posts: 568
Received 0 Votes on 0 Posts
Imaddicted2u : Riello has the turbulator settings nailed down to the nozzle size, no need to change,if your getting 0 smoke all the oil is being converted to heat. If the burner has a automatic air damper no need for one in pipe.Since the flue base stack temperature is up 40f there is now an opportunity to extract more heat from the heat exchanger into the air or water.If you can down size the nozzle without losing the quality of the burn such as causing the flame to smoke,this is the easiest rout, you will still be far above the due point.The temperature at the flue base should be the same as before modification.
 
  #36  
Old 12-14-11, 09:50 PM
Member
Join Date: Feb 2011
Location: US
Posts: 552
Received 0 Votes on 0 Posts
Saves,
Where exactly is the "flue base stack?"

What causes a down sized nozzle to smoke?

I disagree about the burner damper. A 6 inch pipe and chimney have up-down convective air currents. Even with the burner damper closed, lots of heat still goes up the chimney.

Thanks,
Peter
 
  #37  
Old 12-15-11, 02:44 AM
Member
Join Date: Oct 2011
Location: canada
Posts: 568
Received 0 Votes on 0 Posts
PeterNH the flue base stack temperature is measured in the pipe were it enters the chimney to check that the draft regulator is not cooling the gases too much. NTI oil boilers in there installation manual give 200f as a general rule for inside chimneys.A nozzle to small for the firing chamber may cause the flame to cool to fast and all the oil may not burn causing smoke.I don't understand the advantage of an automatic damper that could become a safety hazard if it failed to open and burner was able to fire ,over the burner air shutter such as on a Riello burner.Would they not both being doing the same job.I understand how hot water in a pipe can rise up cool and return to the bottom,is this the same dynamics taking place in the smoke pipe?Thanks Saves.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: