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Jim Davis

Jim Davis

Joined on August 25, 2004

Last Post on May 15, 2013

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Double Acting Gas Barometric

@ October 19, 2011 8:44 AM in Barometric Damper Upgrade to Atmospheric Gas Steam

Barometrics control the outlet pressure of a vented appliance which in turn controls the amount of combustion air that enters the burner.  Without controlling this pressure the amount of combustion air supplied to a burner is more or less random selection.  I learned from the very beginning that you must control both fuel and air, and yet the industry today still denies it.
Drafthoods basically disconnect the appliance from the chimney and allow uncontrolled combustion air and venting.  If the chimney is not connected to the appliance then it is connected to the building which means the building pressures have a bigger influence on draft.  They were specifically invented to keep pilots from blowing out in the 30's.  Because there were no safety pilots back then it seemed like a good idea at the time.  All gas equipment originally came with barometrics.
With a barometric you now know how much air is being delivered to the burner.  With a combustion analyzer you can now maximize safety and efficiency of the equipment.  Since 1980 when I started to teach contractors how to install them and adjust them and tune equipment we have seen saving of 5% to 15%.  Also rusting, corrosion, condensation issures seemed to disappear.  Whenever there is rust there is a venting problem 100% of the time..  If there is a drafthood there is no control of venting, combustion air or safety.  Barometrics with safety spill switches provide maximum safety, minimum wear and tear on equipment and the possiblility of maximizing efficiency.
Barometrics when retrofitted on most gas appliances are set by combustion analysis not a draft reading. 
In my class manuals the biggest print we use states "If you can't control the flue, you can't control the appliance!!"

Draft problems

@ August 23, 2011 8:54 AM in Draft Problems

Any time draft goes down when another common vented appliance is turned on indicates the flue is too small or restricted.  One exception would be if the flue gets wet.  Draft can drop 2 or 3 times lower when a chimney is wet versus dry.  Does the flue have a rain cap??  If not, install one and the problem should go away once the chimney is dry.  There are ways to make equipment work in undersized chimneys without adding liner.  The worst thing to do at this point is make the chimney smaller.

Gas company liable??

@ August 10, 2011 12:36 PM in Lofgren case coming to a head...

So if someone leaves their car idling in the garage and gets CO poisoning, that is the gasoline companies fault for supplying the fuel?
I know legal fees can be expensive so I am guessing it was cheaper to settle than to fight it out in court, but I still believe that is an admission of guilt. 
I guess money will always be more important than the truth!

NOX filtered

@ June 24, 2011 8:08 AM in Whoever said oil burners can't produce CO

I agree that the Bacharach will always read higher than the Testo but usually only 20-30ppm not 80ppm to 100ppm.  Sounds like a calibration issue.  After a couple of years CO sensors can drift higher or lower. 

manufacturers permission

@ June 15, 2011 4:36 PM in Lofgren case coming to a head...

You just have to know how to phrase the question so they are not sure what you are asking!
Like "Is it okay when we install your boiler we make sure it is operates safely?"
or "Is it important that we make sure your boiler vents properly?"

Aspen Case

@ June 15, 2011 10:56 AM in Lofgren case coming to a head...

I it interesting that as far back as 1977 CPSC indicated that there were not adequate safety shutoffs on equipment should a flue become blocked or disconnected but they denied a petition to mandate any action.  They felt it was up to manufacturers to take on that responsibility.  Obviously this wasn't the first or the last sealed combustion appliance to cause a death.
In 2009, the chief technical advisor for AHRI (formally GAMA) wrote an article in ACH&R News stating that equipment was safe enough and no attempt should be made in the field to make it safer.  This was a direct attack against me teaching to add additional safety switches in the field. 
I agree the industry needs to take a universal stand and not fault one manufacturer because they are doing the same thing as everyone else. 
This also confirms the fact, based on current industry standards, that licensing, taking out permits and getting inspections guarantees nothing if every thing is done the way its always been done. 

Oil CO

@ June 7, 2011 8:29 AM in Whoever said oil burners can't produce CO

For years the oil industry stated oil doesn't make CO and if it did there would be so much smoke you wouldn't need a CO detector.  They have been wrong since day one.  My first exposure to CO and oil was in 1984 testing a 90%+ oil furnace.  Zero smoke and 5000+ppm of CO.
I am not sure how many have ever been on the fuel rich side of the combustion curve but if you have then you would know that O2 exists on that side and the richer you get the higher the O2 gets. I have only seen it on industrial applications on process equipment.  Bercause I had CO analyzers that went as high as 100,000ppm I was able to tell the difference.  Watching the O2 reading drop as you decrease fuel input was initially quite confusing and didn't make sense, but I knew I was going in the right direction.  But then the O2 dropped to zero and started rising again as I got to the excess air side of the curve.  Therefore neither O2 or CO2 can tell you which side of the curve you are on, only CO and smoke can.  Of course they exist on both sides of the combustion curve also. 

oil vs lp

@ April 13, 2011 4:05 PM in oil vs. gas

Based on your fuel cost a less efficient oil boiler would cost almost $900 a season less to operate.

Typical result

@ April 13, 2011 9:42 AM in Can't get warm

Since the 80's people have been saying that if you fix the building, the heating and cooling system will perform better.  Wrong!!  Most problems are the heating systems and the duct system not being adjusted for true performance and balance.  Studies have shown that the majority of homes that have supposedly been weatherized and duct systems sealed have seen little or no improvement in their utilities bills.  In one study in Iowa, every home that was weatherized and their duct system sealed saw an increase in their utility bills. 
You really need someone that is certified in combustion and air balancing to solve your problem.  It is not a requrement for building auditors to know anything about HVAC systems.

CO vx CO2

@ April 13, 2011 9:14 AM in Something you may not have considered.

Scary stuff, however the media still doesn't know the difference between carbon dioxide(CO2) and carbon monoxide(CO). 
There is a build up of CO2 not CO.  We inhale O2 and exhale CO2.

oil btus

@ April 13, 2011 9:09 AM in Service manager

The btus produced by any fuel is determined by the temperature of the flame while it is burning.  The temperature of the flame is determined by how much excess air is mixed with the flame.  If your CO2 is 12% your flame temperature and btus produces are the same regardless of what pressure your pump is set or how hot you pre-heated your oil.  However unless you run higher pump pressures and keep your oil warmer, it is hard to burner 12%-14% CO2 and stay clean. 
Saving 30% could only be accomplished if the original setting were screwed up in the first place. 
Using higher pump pressures, warm combustion air and warm oil will accomplish everything that they are claiming for a lot less investment.

Equipment ratings

@ April 13, 2011 8:50 AM in Are boilers next?

It is a shame that everyone puts all the efficiency emphasis on the rating of equipment versus its actual field performance after it is installed.  Most 14 SEER a/c in the field have been tested to only be running at about 8 SEER after they are installed.  95% efficient furnaces are running around 59%.  Efficiency ratings are faked performance based on fictitious government standards.  When one actually measures delivered btus versus how much fuel they are paying for there is a big difference.  Actual operation efficiences can be brought up considerably, but not near what equipment is actually rated.
But then every rule our industry follows has been written by someone with no actual field experience.  Maybe someday verification of performance will become the rule instead of the exception. 

Wood analysis

@ December 22, 2010 12:13 PM in test woodsmoke with oil gas analyzer?

Yes you can use a combustion analyzer to set up a wood appliance.  I have used them on residential and commercial.  Wood and coal are both solid fuels and you can use it on both.  They have filters on them to filter out the debri.
Controlling draft on wood or any fuel helps make the fuel burn hotter by controlling dilution air.  Therefore you will have less creosote on wood if it burns hotter.  On wood the CO reading is the most critical in the set-up.  It helps establish the under-fire air and the over-fire air, minimum and maximum air.  The lower the CO the more you know you are going in the right direction.  The lower the CO the more complete the combustion and the less ash.  On coal it is less clinkers.

combustion material

@ November 30, 2010 8:16 AM in An excellent reading resource...

Jim B has been to the class and which is where he got most of his initial information.  Jim is a good guy and very intelligent and we get along just fine.  I think he has learned quite a bit since he wrote this information and would probably like to change a few things.  However, he has to be politically correct, so he still includes many fallacies in this material to please certain egos.
It is good information, it has to be, most of the beginning came from my material and studies.  Very little information on what is wrong if you are not in range or any real solutions to actual problems.  With just what is written in this material you might find a problem but wouldn't have a clue what is causing it or how to fix it.

Testo Manual

@ November 29, 2010 2:09 PM in An excellent reading resource...

Mark,
Do you agree with the comments in the manual that state you should never go outside the manufacturers recommendations or you should never modify equipment?
Can you calculate airflow using a combustion efficiency calculation and a Delta T?
Where would you say he got most of his combustion numbers from??
Of course then it states that if the combustion numbers are outside the ranges it really doesn't matter that much.  What???
Sorry, when people re-write my life's work and then belittle it at the same time, I get a bit perturbed.

not the first time

@ November 29, 2010 1:38 PM in Death by criminal stupidity

Was involved in a similar court case a few years ago in Akron, Ohio.  A friend or neighbor was nice enough to take off the reg tag and turn the gas back on and two people died.  3 contractors that had sent salesmen to quote the people on a new furnace were sued for not adequately warning the homeowners that their existing furnace was dangerous and should not be used.
The guy that lit it, never found.

barometrics

@ November 25, 2010 2:40 PM in barometric damper

Let me make a little addition to Tim's comments.  A law of physics states that for every action, there is any opposite and equal reaction.  The amount of draft in a flue has a direct influence on how much air a burner delivers in the combustion chamber, whether it is a power burner or an atmospheric burner.  As the draft changes, so does the fuel/air mixture. A barometric automatically adjusts for changes in the draft so that the outlet draft of an appliance never changes.  This means we have controlled and stable combustion.  Any appliance that is connected to a flue that has negative draft and does not have a barometric, has an unpredictable air to fuel ratio.

Get Well

@ November 18, 2010 4:38 PM in I want to let everyone know I am recovering

Get back soon Tim, I am sure everyone is rooting for you.

combustion analyzer

@ November 18, 2010 4:36 PM in Combustion analyzer

The biggest problem I have with TPI is none of the sensors are field replaceable and has to be sent back.  The least expensive is the Bacharach Tech 60 but its CO range is only 2000ppm.
The next least expensive is the TSI which goes to 10,000ppm and both sensors are field replaceable.
The Testo 327 would be next.  Tru-Tech tools sometimes has specials on these.

combustion testing

@ November 12, 2010 2:26 PM in CO Detector

Where do you live??

venter

@ November 12, 2010 2:21 PM in Weil-McLain EGH boiler issues.

You are absolutely correct!!  The venter should actually run for several minutes after the burner shuts off.  However most are set for 20-30 seconds and have to be modified with additional controls.  Sounds like a board problem.  This boiler could start sooting up very quickly and be very dangerous.

Cleaning old boiler

@ November 12, 2010 2:16 PM in Any solution to really high carbon monoxide test results?

Hopefully the replacement boiler was a newer high efficiency boiler not another cast iron boiler.
Most the time the boiler sections just need to be brushed out with some good boiler brushes.  Techs that work on oil have done this for years.  It doesn't really take a specialist.  It takes a specialist to tune up the burner and verify proper venting and combustion air.  There are some people out there that are lucky to be alive. 
Think  of how many other pieces of equipment haven't ever been tested properly with a combustion analyzer.  To totally diagnose combustion problems it is necessary to know the O2 reading, flue temperature and CO and watch them over time to make sure the O2 and CO are stable.
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