Draft Hood vs Barometric

gerry gill

on atmospheric units equipped with the dreaded mushroom hood.

Unknown

Just curious

How many are finding they are removing or plugging off many draft hoods on design equipment and replacing them with a BAROMETRICS?

Second question how many are putting in BAROMETRICS with Power Vented equipment before the power venter (on the negative pressure side)?

J.C.A._3

Sorry Timmie,

I have installed a few, but only because they are specified with the equipment.

I'm still not ready to assume financial responsibility for an unauthorized change. You taught me why, but the manufacturer still makes the rules that I follow. Chris

Nick W

door curtain effect?

can someone please explain what this door curtain effect is,
with regards to the mushroom style draft hoods.

thanks

Brian_24

Sometimes the draft is pulling dilution air so strong it creates an air curtain across the vent opening from your appliance. When you check the draft you will think everything is venting fine, but when you check stack temp, CO and O2 levels you find the appliance is spilling around the burners. This problem is fixed by using a barometris and adding additional safety switches. Hope this helps,
Brian

Nick W

yes,thanks brian,

so your saying,if the draft is so strong,it will cause this.

at what draft pressure(measured above the draft hood)would this begin to happen?

i know you have to anylize the gasses to see if this is happening,but at what pressure would you need to justify the barametric install(even if the gas combustion is ok)
i know draft will increase on a colderday,and following the manufactures draft allowance is required.

all im asking is at what pressure do the warning bells sound.

thanks

Mark Eatherton1

As with any heating question, the only correct answer is...

It depends..

You have to test before you know you have an issue. Just getting a specific negative reading doesn't dictate the condition. A combustion analysis will show high O2 and excess air. It's also important to make sure you have the required negative pressure at the breaching. I've seen some appliances who had ZERO negative pressure at the breaching, and -.04" WC down stream of the mushroom shaped draft relief hood. That was causing a pooling of CO2 that was causing problems with sustained ignition at the bottom of the boiler.

You have to TEST TEST TEST.

ME

gerry gill

yup, like Mark says,

you have to test each unit to see what gives..when there is a problem i usually see excessive draft on the chimney side of the mushroom hood and no draft on the unit side..i also only have seen this when the units discharge to the old coal boiler chimneys, but thats mostly what we have here..one has to drill a hole and take an actual reading below the draft hood, as holding smoke under the draft hood would lead one to think all is okay..use the same hole for your combustion analyzer also..i usually see low oxygen, high co2,high co, and excessive stack temperature when this is happening..not to mention sooted sections..

ed wallace

draft and testing

I just installed a wiel mclain eg 40 steam boiler how do i do a combustion test on it the draft hood hangs off the back of the boiler

Mark Hunt

Ed


Take your readings from inside the draft hood off the back of the boiler. Put the probe into the boiler and test from side to side.

Your other readings will be taken from the hole you drill above the draft hood.

Hope this helps.

Mark H

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Unknown

Curtain Effect

It is a well known fact that most gas equipment comes with a draft hood as part of the equipment. Some are external others are built in to the heating equipment. Draft hoods may in many instances have a problem regulating the flow of air into the flue and/or through the appliance. The draft hood is supposed to neutralize the affect of stack action (exceesive draft due to high stack temperature). Picture it this way it is a fixed opening that cannot be adjusted. It may be working when you are there testing but what about changes in conditions? The other functions of the draft hood is to provide for the ready escape of the flue gases from the appliance in the event of no draft, backdraft, or stoppage beyond the draft hood. What this is saying is that it allows flue gases to spill back into the room. Those flue gases are CO2 which acts to dilute the air for combustion and eventually may cause a poor combustion condition which is Carbon Monoxide. The draft hood is also supposed to prevent a backdraft from entering an appliance. With gas this is a problem because of the explosive charcteristic of the gas. I hope those who are installing barometrics in place of draft hoods are taking care of the possibility of a backdraft?????

In some cases the draft hood can allow too much dilution air flow, evidenced by a low draft reading on the equipment side of the draft hood and a higher draft reading after the draft hood. This is also cooler room air usually 70 degrees mixing with air over 300 degrees. The "curtain effect" is this allowing too much dilution air flow. The "curtain effect" exists when a higher volume and velocity of cooler room air enters the draft hood and creates a restriction of the flow of combustion gases out of the combustion chamber. This forces the combustion gases to spill into the structure. This will typically be out the front of the equipment burning and scorching along with a potential for fire or damage to controls. Then of course the fact that carbon monoxide is being created and is now spilling into the dwelling. The draft hood design actually disconnects the equipment from the flue and chimney and isolates the equipment.

The double swing barometric (single swing is used on oil) draft control maintains a consistent air flow through the appliance and prevents the "curtain effect" combustion which in turn increases safety and efficiency. It is able to adjust to varying changes to draft, atmospheric pressure and other changes that a draft hood cannot adjust to as it is a fixed device.

My mentor Tom Roche of T.C. Roche Associates and I did many tests on this back in the 1960's. The data compiled was in conjunction with draft hoods on conversion burners versus barometrics. Tom was with Midco the designers of the Economite burner. I took the study a step further and tested some design equipment. We offered our findings to the American Gas Association and they were rejected.

In the 1990's Field Controls in conjunction with AGA conducted tests on Drafthood versus Barometrics. The findings are availbable in reports from AGA as follows

Report # FT-C-07-93

Report # FT-C-12-93

Report # FT-C-13-93

The problem that exists today is this. In spite of those findings the Gas Appliance Manufactuers Association (GAMA) did not accept those findings. Today design equipment continues to use draft hoods and they are a part of the design of the equipment and when you alter them for what ever good reason you may have and I am certainly not advocating change just for the sake of change but you must do extensive testing to determine safety and efficiency. I am also not looking for a debate with anyone concerning why it is not a good idea to change the design of equipment without manufacturer involvment.

I think we are all agreed that a barometric will work better and safer. THEN WHEN ARE MANUFACTURERS GOING TO STOP USING DRAFT HOODS??? That is the question, if all of us just keep altering equipment without putting pressure back to the designers then nothing will be done.

What am I advocating it is just this when you make the alteration and if you are secure enough in your findings to do so. Then take pictures and submit a report to the appliance company. This is the only way change will ever take place. This is my concern which I am sure many of you have mis-interpreted for some time. I am not against changing from a draft hood to a barometric and was convinced a long time ago that is works better. All I am saying is let us try to get permission or maybe even cause the industry to change by putting pressure at the point it needs to be applied.

I await your comments.

By the way we have not even talked about fan assisted equipment vented with natural draft equipment and the problems that presents. That by the way is allowed by the charts and tables in NFPA 54/ANSI Z223.1 National Fuel Gas Code and also International Fuel Gas Code.

Jim Davis_6

drafthood vs barometric

If one would go back to the original design of drafthoods they would see they were meant to be moveable devices. There was a minimum height that they were supposed to be installed and a token spillage test was taken. If the appliance was not venting sufficiently the drafthood was supposed to be raised.(I wish I had kept the manuals I saw years ago that said this). I have been told more than once the drafthood was the most dangerous device ever invented. How did drafthoods become attached? Because of low ceiling clearances certain boilers could not be sold. So in order to make it fair, the low profile, attached drafthood was now allowed. Back in 1980 when I was selling Hot Water Reclaim coils for boilers, I became introduced to the barometric. These hot water coils were installed in the flue to reclaim as much as 40% of flue loss. Installing them above a drafthood was useless because the flue temperature was already diluted. Therefore it was totally approved to block or remove the drafthood, install the coil and put a barometric above it. Although manufacturers didn't like it, they were forced to accept it much like flue dampers. What happened after that was amazing. Combustion became totally stable(barometric maintains fixed airflow across the burner). Rusting and sooting became a thing of the past. After a proper tune-up gas usage dropped considerably. I do not recommend those that are not qualified to make these changes. Those that are afraid of liability are in the wrong business. Obviously combustion testing is required to make all adjustments. Spill switches are also mandatory! I get tired of reading all the stories of people getting injured or dying from drafthood equipment that is designed to operate if the flue gets clogged.

Nick W

scary

thanks to all about air curtain and then some

its a scary thing sacrifycing safety for economics
you guys are sure knowledgable

and when the manual says hold up a match,and if it sucks in,
your good to go-SCARY

Mark Eatherton1

Question Tim...

Why are oil dampers single acting and gas is double acting? I've seen two oil boilers in my whole life, so I haven't the foggiest.

As for the manufacturers, some of them (Teledyne Laars) do allow barometrics on some of thier boilers.

Others tell me the hair stands up on the back of their necks when I mention adding a baro to their boiler, because they're not certified to be operated that way. I guess they don't understand the operation of their own equipment sometimes.


ME

Unknown

So do we continue

to do this with no regard to seeing a change in design for gas equipment. Oil systems have been using barometrics for years. What kind of pressure can we put on the industry. Dan talked about forming an association to be able to influence what happens in our industry is that something we can do here or are we more concerned about piping and systems and all the stuff that does not kill anyone.

My discussion on this subject over the years with equipment manufacturers always comes down to cost to change designs. The problem is many furnaces and boilers have the draft hood built in to the equipment. That means a major design change and then testing to new standards.

What do you say do you think is it important enough to do something to make it happen?

How about it some of the manufacturers who post here what are your feelings on this subject. I know several of you have been to NCI classes, did that impress you enough to work toward a design change.

Should we all be removing or blocking off draft hoods? Assumption here that you have been trained to do so, DO NOT JUST GO OUT AND START DOING THIS WITHOUT TRAINING. That is not what this post is about.

If this discussion has awakened you maybe you need to get some training.

Maybe it will all just go away as new designs eliminate the draft hood with power venting and direct vent. What do you think?

Weezbo

Tim, though i understand these draft hoods avec spill switch

i personally dont like them.to be sure combustion of nat gas and its vagarities are different say than oil however ,...there is something about a large gaping hole in the exhaust trail of combustion equipment that just gives me the creeps...dont think i havent done a few commercial kitchens and the electrical and fire suppression and alarms ,outside air etc.. ijust think of these hoods more of being monitored full time like a hospital steam boiler or whatever where some one is constantly aware of the operation of the equipment. two way barometric on nat gas to me seems the preferable appendage on a residential boiler/furnace. or a fixed gotta run to nat gas class....

Kyle Kubs - Benchmark Home Inspections

Lot of good Info

Lot of good information here Tim... Thanks. Your hands must hurt from all that typing... I always check for spillage aroung draft hoods and of course look for scorch marks around burners, but I will be more dilligent now and will find it easier to explane what is going on in the instances when I do find this...

Kyle Kubs - Benchmark Home Inspections

Lot of good Info

Lot of good information here Tim... Thanks. Your hands must hurt from all that typing... I always check for spillage aroung draft hoods and of course look for scorch marks around burners, but I will be more diligent now and will find it easier to explain what is going on in the instances when I do find this...

Unknown

Tim

I think the point that you are missing with this post is that the VAST majority of contractors and service people out there installing boilers and other equipment certainly are not equipped with the instrumentation and knowledge to either install or properly set up a barometric on gas equipment. Every single day I am involved with service people that are not equipped with something as simple as a manometer let alone a draft gauge or combustion instrument. You have worked your way up through the years surrounded by these people so you know the ones I'm referring to.

As you very well know the equipment manufacturers have fitted the boilers with Blocked Vent switches as well as Flame Rollout switches as methods of safeguarding against spillage out of the draft hood or curtain effect causing excessive temperature buildup within the appliance. I do see barometrics installed in lieu of draft hoods from time to time but in many cases they are the wrong type and with no thermal switch to guard against a backdraft condition.

Although you and many others here on this site are equipped to Test, Test and Test again, reality dictates that there are way too many others that are not. Until that changes I really somehow doubt that you will see design changes involving equipment being outfitted with anything but a draft hood and thermal safety switches. We all appreciate the knowledge you are willing to share and as you know, you, I and other people involved in training have a tremendous task at hand in bringing the trade up to a much higher standard.

Glenn Stanton

Manager of Training

Burnham Hydronics

www.burnham.com

Unknown

Thanks Glenn for your input

and I hear what you are saying. The question that I have asked for years is why then do oil boilers come with the need for set up and adjustment with barometrics. I guess the folks who do oil installations are just more qualified than those that install gas and have better equipment.

I think it should be mandatory for a combustion test to be done on all equipment as part of the installation before operation of the equipment is allowed.

You are correct Glenn we have our work cut out for us. It is very hard to get trades people to be interested in combustion training and learning all the fundamentals that you have to know.

Unknown

I might be giving my age away!

Back many years ago when I started in this business, I recall many, many old timers that set up oil burners by eye. This was before flme retention burners and 3450 rpm motors. The oil industry has progressed in giant leaps and bounds since then and virtually everyone has at least a Bacharach "Shaker Bottle" test kit to check equipment now. Many are fortunate to have electronic test equipment to use now and are able to test for CO.There are still a chosen few that set-em-up by eye but you and I both know who has to correct those situations. Heck, I remember a gent in RI that used to check for 120v electrical current by wetting his fingers and bridging the terminals. Watched him do that one day while standing in about 3" of water at a jobsite in Middletown, RI. If you are still alive "Andy" ..... God Bless You!

My feelings about the gas side of the business is the fact that in the old days the testing was most always done by the "Gas Company". We all know that in many cases this is no longer so. As you also know, many of the properly trained Gas Company people have their own service companies now or possibly are out there training others (like someone I know named Tim). There just don't seem to be enough of people like you, me, Jim and others out here to get everybody properly trained in an orderly and progressive fashion. I think NATE is doing a good job with the HVACR side of this business but there are many people out there that don't work with warm air heat. Until then....let's keep on pluggin'!

Glenn Stanton

Manager of Training

Burnham Hydronics

www.burnham.com

Mark Hunt

Good post Glenn


Fact is that most of the "testing" posts fall on deaf ears. They have NO idea what we are talking about. No fault of theirs, they were never told. The manufacturers have to make equipment that will operate "out of the box" because MOST installers are not educated beyond that point. Timmie, Firedragon, Jim Davis and all the other trainers can testify to this.

I wasn't born with the knowledge I have, I had to go find it. I installed countless systems that I would now condemn before I learned what REALLY happens when we SET STUFF ON FIRE.

Glenn Stanton from Burnham has attended a class by Jim Davis. As far as I know, he is the only rep that visits this forum to do so. Glenn gave Jim Davis a positive review, not an endorsement, but a positive review. I have seen other "reps" slam Jim Davis and they have NEVER attended his class. How much weight do those OPINIONS carry?

If you really want to put your finger on "the pulse" of the hydronics industry, go rent the movie "American Graffiti" or "Hollywood Knights". Seems like we're stuck somewhere in there.

The Gov't is already involved in this folks. If you doubt that, go ask the water heater manufacturers and when you're done with them go talk to the folks that make A/C systems. You think your furnaces/boilers are safe? HAHAHAHHA! Get ready.

But this has nothing to do with understanding what happens when we set stuff on fire. I don't care whether it's sealed or not, WE ALL NEED TO UNDERSTAND WHAT IS HAPPENING WHEN EVERYTHING WORKS, WHICH MEANS IT IS ON FIRE!

The law of averages dictates that someone was poisoned or killed by a system that was "serviced annually" by a "reputable contractor". Feel better?

So now we come to the question., “should I leave it alone or should I make it safe?”……………Well if you installed it according to manufacturers specs and it proves to be WRONG, who is at fault? Who gets sued? How do you determine if it is safe?

Of course EVERYONE here at The Wall tests and so if a consumer chooses one of the wallies, they have nothing to fear right ?Hehehe!

Get to one of Jim Davis’s classes.

Mark H



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Unknown

Double Acting Barometrics

required on gas to preserve the low end of draft in particular when only the pilot is operating and has to get its products of combustion out of the chamber. The draft regulator being able to swing both ways will preserve this low end of draft. The double acting will open to relieve positive vent system pressures as low as .001. It also allows control of draft at levels higher than those permitted with a draft hood. The other thing is that by swinging both ways it will allow a downdraft to be relieved. It is still required to have a thermal safety switch installed.

I have recently had two jobs (boilers)in a duplex seperate chimneys that I sealed the draft hood and installed a barometric in order to solve some severe problems. Low outside masonary chimneys. The pilots would not stay lit on these and they had been converted to spark ignition and they would not stay lit. Combustion problems do not go away just because you put in spark ignition. These jobs had been red tagged by the gas company and left off.

We had these running at maximum efficency with very low CO and no ignition or venting problems whatsoever. The gas company came in to reinspect in order to remove the red tags. They left them shut off due to barometrics being installed in violation of NFPA 54 Section 8.1.14 and 8.1.15. I sited 10.12.4 as a reason to install the barometrics. THEY WON End Result both boilers are being removed by the landlord as faulty. Guess what they are putting in two new boilers into the same chimneys. You just cannot win. The landlords answer to me was the gas company I am sure knows a lot more about this than you do. He still did however pay me for what I did.

Unknown

Unfortunate Circumstances

There can also be circumstances that no one would have seen happening. One of these involved a gas furnace installed in a modest ranch house in Coventry, RI. Unit was installed per manufacturers standards in an interior closet central to the slab constucted home. Combustion air was drawn through a louvered door facing the kitchen and was deemed proper and adequate by both the inspector and gas utility. The elderly father and his son who shared the home had the furnace cleaned and serviced and went on vacation to Florida the same week. The night they returned they sat in the kitchen and threw on a pot of coffee. Who would have known that a couple of very diligent spiders would build a nest web large enough to almost completely block off any combustion air to that gas furnace. They found the father and son the next day with coffee cups still in hand.

I guess the moral of the story points to proper installation, proper venting, proper combustion air and proper knowledge being the biggest preventive measures to the woes of CO. Even with all of this working for us though there may still be simple things like spiders that can turn things upside down!

Glenn Stanton

Manager of Training

Burnham Hydronics

www.burnham.com

Mark Hunt

Yes Glenn


A simple test could have saved their lives.

Thanks for all that you do!!!!!!!!!!!!!!


Mark H

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Unknown

Well

I'm not so sure that a simple test would have saved their lives....but a CO detector would have!

Glenn Stanton

Manager of Training

Burnham Hydronics

www.burnham.com

lchmb

Hi Glenn

I wish I had a quarter of the information you gentleman carry in your head's. My point of view on this entire discussion would come down to "at what point". Glenn you mention that alot of people do not have the equipment to install a barometric properly. If that's the case then they are not equiped to set up a drafthood either. Waiting for people to catch up before we move forward doesn't seem like the right answer to me. I can understand why a company might be a little skeptical of designing a system that requires special equipment to set up. it may not sell, they may not understand how to repair it. It may have problem's if not done properly...ect ect... Even equipment with a drafthood has its problem's. I wonder how many people have health issue's and no one ever notice's the problem because it's ok when it get's inspected in the summer or with the door to the boiler room open....

It would probably amaze manufacturers how much of their systems are butchered in the field. Or maybe it wouldn't. On the gas side I see roll out switch's jumped out and stack switch's disconnected. When you ask how they thought it was safe, simple response, they checked it with a match. Then again I also see this done on oil, especially with power vented unit's and oil tech's use barometric dampers and (should) have testing equipment.... I do both product's so I am lucky (I think) enough to see both sides.

Maybe it will have to start out like wardflex or some of the other special equipment. If your not certified you cannot purchase it. Doing something seem's better than nothing to me....JMHO..:)

Weezbo

i may suprise you as i would also like to explain the old Ways

not only did the old timers use thier eyes, i dont want to school any one in the lost arts buh....the ears are also part of the old syle "test equipment,as was that hand on the stack above the barometric damper....missed that part ?...oh and when they opened the view port and lit that old stogie or ciggarette....did you know they were doing more than looking at the flame and that casual hand ,over the air band setting while lighting the ciggy ,...and the final tightening of the gun in the draw...:)) now i aint saying the old boys were absolutely perfect buh dammit give em a little more credit yah ihave owned a few bacharach and a lynn i also savey what many of the older guys failed to apprehend when not paying absolute attention to the Old Ways ....there way a little more going on than met the eye...for sure *~/:) now that i belive at least i made an honest attempt to divulge old timer trade secrets ...:) would you and timmie be astounded to hear the old indian actually knew a no smoke from a one smoke? i better not get into urinating any of you off as the instrumentation does at least verify in my mind that they indeed knew a thing or two...

Mark Eatherton1

So...

What I hear you saying is that it's OK to dump products of GAS combustion into the room, but not oil...

You're right. Its time for an uprising. Count me in.

Thanks for responding.

ME

Mark Eatherton1

Glenn...

How do spiders building nests kill people? I agree, a CO detector might have saved them, but I've seen situations where excessive CO was being dumped into a working stack,
and nobody even knew. If the gasses had backed up, people would have died...

What caused the flue gases in this case to back up and spill? Was it coming from the range or from the furnace?

The usual excuse, "defective gas appliance" , just don't cut it with me. There HAS to be more to the story than spiders...

Call me curious.

Thanks, as always for your input.

ME

Unknown

The point

that I was trying to make was that there is no setting up of a draft hood. That is done by the manufacturer in order to pass the required certification processes. We do occasionally see draft hoods that have been cut down so that the flue pipe will fit into a preexisting chimney thimble. If there are issues with draft or down drafts the blocked vent switch will generally catch it and tripped out. If there exists a condition whereby the flue gasses are backing up through the heat exchanger then the Rollout switch is there to catch it. That is the case provided these safety devices are not jumped out. As one of my coworkers once said "There is no such thing as idiot proof because there will always be a better idiot!".

As Tim stated above a conventional standing pilot boiler will more than likely require a dual acting barometric damper. In addition to this a thermal safety switch is required on the boiler side of the damper. The point I try to make in my seminars is that if the installation is correct, the fuel supply is correct, the venting is correct and combustion air is correct then the appliance should operate should be operating correctly well within the safety standards. The two biggest culprits I see in the field that violate this are Combustion Air and Gas Pressure. Replacing a draft hood with a barometric is not going to correct either of these. They are part of the proper installation!

When I visit a jobsite that has a gas boiler continually dropping in and out I always ask what the gas pressure is. Sometimes I get a real answer and sometimes I get an answer like "Theres's plenty of gas!". Three times last week I was told that the gas pressure to the boiler was in excess of 5" on boilers that were intermittently dropping out. When we got there and tested we had 5" of static pressure but that dropped to 3" w.c. after ignition. It's hard to get 3-1/2" w.c. at the manifold when you only have 3" w.c. to the valve!

The majority of jobsites I visit are absolutely starved of combustion air. There are so many alternatives available today to deal with confined spaces but they are seldom used....probably due to extra cost, wiring or vent piping terminations through the wall. Combustion air is a huge issue and has to be dealt with in order for an installation to be correct.

Sorry to stand up here on the soap box and preach but in my opinion altering the way a boiler is shipped, tested and certified will not change or make up for an improper installation. Hope this helps.

Glenn Stanton

Manager of Training

Burnham Hydronics

www.burnham.com

Weezbo

Howdy Mark....*~/:)

you would probably like this as it is sorta a mystery ..:) and the scientific mind Hates a mystery well, the oil fired burnham went off and locked out,so my buddy called an oil tech. he fricked with it a bit handed him a bill and split....couple days later same thing ...buddy calls another out fit they come over frick with stuff sell him a part hand him the bill, and split.next day he gives me a call i say i am buzy buh sounds like maybe the the primary or the fire eye..er cad cell. so he goes down gets the primary and fire eye hooks them up ...works fine next day its the same deal....i dash by take a look , pull the draw band check the thing..ok i brush it so it is clean...clean the pipe ..fire the burner all is good ,check th smoke etc alls well ...split.....next day he goes over and turns the thing off in the middle of the day ,i stop by wonder what the heck is going on ,...recheck everything turn it back on ,split that night he calls tells me that he had turned it off during the day and some howit was running again ...aitell him all is ok .next day its off again ...he calls me i come by what in the world is Wrong with this thing...i go thru every thing i can test NOTHING!....so , i figure ok i watch it tru two cycles again and see if there is something i could be overlooking...nope all is well. next day its off again...i do not have the time to keep fricking with this pos so i figure well, i recommend so an so...he goes over every thing checks out ok he hands him a bill splits. next day and man i am really really beginning to HATE this problem...so i think well maybe some how on gods green earth there is a pinched wire or something so i put a dollar into another primary and matching fire eye and put the other aside for use in a pinch....bring bring ..it is off again....i tell him i am sorry buh this is not in my repitore..i cannot determine what the problem is...i honestly cannot determine what the reason IS.so he calls another guy...i see him in the store and get a cup of cofee and ask him ...he says ..is that just around the corner from here? so &so? he says Pure sh luck i figured it out.ok so like i am not one kinda stuopid for no reason so i ask what was the problem ..."Gnats! no seeums!" "what?!!!" "the things were living in the boiler and flying in and out of the thing"..... who can argue with the experience that God lays on us:)))i shoulda figured it out ...i mean what the heck...i noticed them and just couldnt see the correlation...

Unknown

Mark

The combustion air was being drawn through the louvered door from the conditioned space. The furnace was atmospherically chimney vented. Apparently the spiders built a web that blocked off the majority of the combustion air that was available to the furnace. This probably was compounded somewhat by airbound particulate being caught up in the web. The report in the Providence Journal didn't state whether cleaning the louvers in the door was part of the furnace cleaning the previous week, but I doubt it was.

Glenn Stanton

Manager of Training

Burnham Hydronics

www.burnham.com

Unknown

Weezbo

I still use the ears (even though one doesn't work too well anymore) and I use the hand on the barometric to feel for loss of flame retention. That works well for me but the instruments take the guessing away as far as where you are in the narrow band between good and bad.

Glenn Stanton

Manager of Training

Burnham Hydronics

www.burnham.com

Joannie_5

Manufacturers

Good points, Glenn.

We (Laars) redesigned many of our atmospheric equipment back in the 80's and early 90's, removing the mushroom-style draft hoods and going with integral draft diverters. We currently only build one atmospheric type that uses the mushroom-style draft hoods. We made these re-designs for two major reasons:

1) People did not want the height of the separate drafthood.

2) The draft hoods that were sent with the products were sometimes not being used at all. People were simply leaving them off and connecting to existing vent pipe directly off the unit.

Changing the designs of products again would be extensive and expensive. And, at this point, as the industry is going toward fan-assisted and sealed combustion, we are focussing our efforts there.

As, Mr. Eatherton stated in this thread, we have authorized the use of barometric dampers on some of our equipment, in lieu of the mushroom-style draft hood. That can be a sticky point, because the units are certified with the draft hoods. But, if someone contacts us, asking whether they can use the barometric (in lieu of the mushroom-style draft hood) we can then find out if they know what they are doing, and judge whether we can authorize it with confidence.

I hope this (one) manufacturer's point of view helps you.

Joannie

Mark Eatherton1

Thanks Glenn...

I think that it should be MANDATORY for fire fighters and death scene investigators to take the NCI course. Then, they wouldn't be blaming these things on spiders and such.

ME

Mark Eatherton1

Mr. Eatherton???

Is my dad posting here some place that I didn't see :-) If he is, he's doing it LONG DISTANCE, and the Lord is going to be PO'd when he gets that bill...

Joannie, you can call me Mark, like my students and everyone else does ;-) Being referred to as Mr Eatherton reminds me that I'm either in court, or getting old. Neither of which brings a smile to my face.:-)

Thanks for the input.

Mark

Weezbo

or your Moms after You *~/:)

"Mr. Eatherton! come in here and get some fresh cookies"...I" i dont Smell any fresh cookies mom!"..."Wheres that wooden spoon !" )

Joannie_5

Mark

Thanks, Mark. I'll remember that, Mark. Mark, I didn't mean to, Mark, make you feel old, Mark. And I, Mark, certainly didn't mean to remind you of court, Mark.

(And I hope our Dads are posting together up there, and laughing the whole time!)

Markedly Yours,

Joannie

Jim Davis_3

Firefighters

I am going to a fireman's national convention in May in Indianapolis. One of our certified students(Vince Difilippo) a volunteer fireman, also attends every year and is trying to educate them on CO testing and training. Fireman responses to CO is often like some contractors in that is they already know as much as they want to know.

Jim Davis_3

Joannie

It is good to see another manufacturer that recognizes that field situations can be very diverse and factory designs may not conform to all installations and environments. Just recently a boiler had to be modified with a barometric to keep a family from being poisoned. The manufacturer called Field Controls to get a copy of their field report and had no problem with the modification. I supervised the barometric study with my students, AGA, and Field Controls and mandated that the report say only qualified persons should make these changes. Since 1980 I have probably been the most influential person in teaching how to diagnose field problems and verify if this correction is necessary. In life threatening situations there has never been any auguments by any authorities of any type. Engineers at AGA Labs even referred utilities from other parts of the country when these problems occurred in the past. Thanks the the study that was done in 1993 acceptance has improved. I have never discussed how to make such modifications unless the contractor has been through my training. As Glen Stanton has seen after attending my training, very special diagnostics techniques must be used and all repairs require 100% verification of safe operation. These are not random repairs. They are specific to each job. Things that affect operation of equipment such as chimney height, common venting with additional appliances, negative building and room pressure, wind interference are things that can only be tested in the field. All installations need to be tested to work 365 days a year not just one. Induced draft is certainly a step in the right direction but it carries a different set of conditions that must also be addressed. Every job is a fingerprint of itself and requires the highest level of diagnostics skills by contractors to establish each situation. Murphy's Law will always apply especially to the impossible.