Draft regulators / barometric dampers on oil fired heating equipment:
Here we explain the inspection and adjustment of draft regulators or barometric dampers on oil fired heating equipment:
A Guide to Barometric Dampers on Oil Fired Boilers, Furnaces, Water Heaters: inspection, adjustment, cleaning, troubleshooting.
Green links show where you are. © Copyright 2017 InspectApedia.com, All Rights Reserved.
Hi there -- My home has both heat pump and oil heat and I prefer to use the oil. I have a ? - several years ago our elec co came and installed a programmable thermostat as well as doing something to our furnace.
Since that time there have been several incidents that the damper door gets stuck and then "bursts" open with a loud explosion noise -- scary. A local HVAC co replaced the door but the problem with the damper door still exists. T
he hubby has adjusted some weight on the thing but ... You would have thought the folks that replaced the door would know what to do. I'm afraid to have to use it and the heat pump is worthless. Any advice would be greatly appreciated. I reside in MD.
Mary get someone you know who knows heating systems, if he arrives with out his test equipment do not let him try to set up the burner or adjust the draft regulator as its job is to maintain the fuel air ratio when the outside conditions try to change it. It can not be done accurately by eye.
Mary: a bent pin or even out of round opening can cause a barometric damper (draft regulator) door to "stick" closed. It's a simple mechanical repair that is easily performed by an attentive heating service technician. Or if the device is badly damaged or missing parts, it's not costly to replace the whole assembly.
Hubby changing the weight setting on the draft regulator door is not a good idea, though freeing up the door to move is just fine. The weight setting is a draft adjustment. Incorrect draft means incorrect burner operation.
Watch out: a stuck-shut draft regulator results in increased draft over the fire - something that increases heating system operating cost, but not something that would easily explain that loud "explosion noise" when the regulator opens. Rather, I suspect that your oil burner is not properly adjusted, is dirty, or is otherwise malfunctioning.
For example, an oil burner that does not shut down crisply at the end of a burn cycle can dribble unburned oil into the combustion chamber. At the next startup operating cycle that unburned oil is ignited to cause an explosion in the combustion chamber - referred to in the trade as a "puffback". Puffbacks can be dangerous, damaging the equipment and risking blowing soot all over the place, and in extreme cases the whole heating appliance can be badly damaged.
In conclusion I agree with Mr. Scott's advice: you need a service call from a trained, competent heating service technician, ASAP.
HI, I have a oil fired boiler that provides hot water base board heating and domestic hot water. I have just had the boiler serviced which includes cleaning and checking of draft etc. The serviceman is very competent. He has been servicing it for years. The flue is an 8" flue inside of a 10" insulated pipe because the pipe goes up a boxed in chimney of plywood and the plywood is stucco outside. I have a gas fire place also which is direct vented to the outside.
The flue pipe comes up the side of the box and then once it gets past the fireplace vent is offset to the center of the box. I believe the pipe is then reduced at the top to a 6" pipe and cap. It has been this way for 15 years, but suddenly I am smelling exhaust fumes after the burner runs and sometimes after it shuts off. The service man has been back several times and have tried different things and made sure the setting for draft are correct. He said the pipe is very clean and the furnace runs very efficiently
. I only seem to smell the fumes at the first level floor and not in the basement.
The next step would be to remove the outside surface of the box to see if we can see any separations where the pipes lengths connect, but I want to make that the last resort, because of the expense. Is there any other steps I can try to see where the smell is coming from. - Steve Henninger
If your heating appliance was designed for an 8" flue, that is, the diameter at the top or back of the heater is 8" in diameter, then any reduction to 6" is asking for a draft problem. It's true that a heater might appear to work "fine" with a constricted draft, especially if it were set up to give priority to the draft (perhaps at the expense of most economical operation). By that I mean it's possible to set an oil fired appliance to run "hot" to get better draft, and even to run cleaner, but setting hotter than normal wastes fuel, sending more of each heating dollar up the chimney rather than into the building.
Now later, maybe years later, fussy technician shows up, cleans and services the system, and sets it up at what s/he views as optimal for economy as well as safe operation. But now the constriction at chimney top begins to make more trouble.
Or alternatively, the chimney itself has changed - a leak or hole, combustion air supply to the appliance has changed -someone closed a door or window, or site conditions have changed - someone cut down a tree, wind direction changed or increased, etc. Something that just pushes draft problems over the edge of recognition.
I just had my chimney clean and they put the vacuum into the damper instead of going into the sealed opening in chimney . I found my damper damaged the counter weight was on the floor . Is this standard practice in the chimney cleaning business practices. I will be making a complaint to consumer affairs and suing them for exposing me to carbon monoxide poisoning. Neil
Neil, in my OPINION, it sounds as if your service tech may have taken a bit of a shortcut. Certainly if there is an easy direct view into a "dead end chimney flue" through the damper I can understand the temptation to just reach the vacuum in through the damper to vacuum out the debris - an important safety step to avoid a blocked flue.
But if you were having the heating system serviced and cleaned (that is your boiler or furnace was supposed to have been cleaned), on most systems it is necessary to remove the flue vent connector, damper assembly, and flue connection to the chimney as well as the top of the boiler or furnace in order to vacuum out the heater itself.
And if all that disassembly were performed, it would be easier then to vacuum the chimney base directly.
Further, what you describe is not a complete chimney cleaning - just removal of debris from the chimney base. Now that might be all that was needed, provided that the service tech had some reason to be confident that the rest of the chimney was clean and unblocked. Say by inspection using a mirror and light? But it's difficult to look up into a chimney thoroughly - it's like peering into a black abyss.
Finding your damper damaged and the counter weight on the floor is prima-facae evidence of an incompetent technician. No responsible person would leave equipment in that condition. I'd give the heating or chimney company service manager a polite call asking that they send someone with better training and work habits to repair the damper and to inspect the chimney, and if your heater was supposed to have been cleaned, to perform that task too.
About suing your contractor for CO poisoning, I understand that you're rightly annoyed, but in my OPINION that's a costly waste of time and source of unnecessary aggravation for you as well as everyone else. Focus first on making sure that your heating system is properly serviced and safe. It would be in my OPINION a big mistake to start by hiring a lawyer while leaving the heating system in an unsafe condition.
The picture of the hot water heater shows the draft regulator installed at the end of the tee which makes for a possible exhaust leak should be perpendicular to pipe.
I invented a improved draft regulator patent #2459368
I have been asked to prove how much heat a properly set up barometric draft regulator can lose. I have been under the impression that it is 15 to 20% of the total fuel bill. Can anyone help? 11/27/2011
- Lionell Scott
Lionel Scott - thanks for your comments below. I agree completely.
Send us some information and photos of your new draft regulator - sounds interesting, perhaps I can add an article about it here at InspectApedia? use the CONTACT link found at the top, side or bottom of any of our pages. Daniel
Thanks for your interest in the Venturi Draft Regulator, If you would like to have an actual regulator to test i would be glad to send one.
We'd love to see and photograph a Venturi Draft Regulator, to comment further on the product's application, and we'd also welcome any content critique or comment you may have about any InspectAPedia website articles. Our contact information is found at the the CONTACT link at the top, side, or bottom of any InspectAPedia web page.
About proving the amount of building heating cost lost through a conventional barometric damper, the 15-20% of total fuel bill sounds very exaggerated to me. The heating equipment is not normally located inside the occupied space of the home, and is therefore unlikely to be stealing that much heat from the home.
Some thought needs to be given to a properly-designed experiment to make some actual measurements, including
- building location
- communication between the utility area locating the heating equipment and the rest of the structure - heat flows
- assumptions about insulation, R-values, building design, air leakage, and other factors that tend to dominate heating costs
- assumptions about prevailing and average wind direction and speed and its impact on chimneys - with chimney assumptions too.
The guy who cleaned my chimney stuck the vacuum into my damper causIng me to almost lose my entire family to carbon monoxide poisoning o called the guy back and he laugh at me - Alexander Delarge 12/16/2011
My boiler just exploded causing thousands of dollars worth of damage called the boiler company and they told me it's not their problem because it was cleaned by a unqualified chimney cleaner . The cleaner laugh at me over the phone and told me to [... obscenities deleted] - Alexander Delarge 12/24/2011
Alexander, although subsequent posts suggest that you are making up the claim above, nevertheless it merits comment. One would imagine that even if the heating service technician was not competent or did something improper, it sounds as if the problem was more complex than you describe. Just putting a vacuum into a barometric damper itself would not cause carbon monoxide fatalities. More likely there was incorrect cleaning, incorrect heating equipment service, a blocked chimney, or a combustion air fault - or some similar and dangerous condition.
I have a burnham v8 series domestic boiler and the boiler shuts down the Field control barometric damper slams shut when the boiler shuts off. What can cause this problem? - Guy Triano 1/19/2012
It's normal for the barometric damper to close when the boiler stops, as it no longer is required to feed extra air into the flue to control the draft. If the damper is making a slamming noise it may be that it needs repair or adjustment, or that your boiler shut-down cycle is doing something abnormal - ask your service tech and let us know what s/he says.
please state all risks or negatives of a non chimney boiler onside of home through wall with fan as opposed to regular roof chimney. Our chimney being blocked 5 feet away by 6 story building wall of neighbor. need to correct it. advise please - Susan Borchardt 10/22/12
Your question is a bit broad, no. I'm doubtful that we can effectively answer a "tell me all" question in e-note exchange, free or even for pay. Worse, without seeing and inspecting your home we can't address what might be very serious fire or safety hazards that might be present.
It sounds as if you should have an inspection by a chimney expert who can consider the exact conditions of your site and then propose one or more reasonable repair or corrective measures. Chances are you will need to extend your chimney height or relocate it away from neighboring windows to comply with code.
You might be able to eliminate the chimney entirely and go to a direct-vent system (details are at DIRECT VENTS / SIDE WALL VENTS) - which is what you were probably referring to by a "through wall" system. How easy it is to do that depends in part on your heater's location. We've made that change in some homes, but doing so sometimes had to relocate the boiler or furnace closer to an outdoor wall. So be sure you compare *total* costs of such a project.
Hi - I just had a brand new oil boiler/burner installed (Smith Series 8 boiler) and the technician did not install a barometric draft control at the flue pipe. I have never seen a boiler without it.
He explained that I do not need one because when he tested it he saw that I have enough draft (0.2 to 0.4). My upstairs neighbor's boiler that sits right next to mine is the exact same model. It was installed last year with a draft control. I compared the draft test results and they are identical, so this is making no sense to me. Is it really ok not to have a draft control on my flue pipe? And what about access to cleaning the flue pipe? They really can't get into the flue pipe without taking it apart every time, so that can't be good either.
We do not agree with what your service tech told you - it was an incomplete and incorrect reply. Even if a tech sees "perfect" draft at a chimney at a particular time, weather temperature, wind, and other conditions will change constantly at any building site, meaning that draft conditions will change too. In turn, that means that while the heating equipment may run, it is impossible to tune it and set it for proper and economical condition under those varying conditions if there is no way to regulate the draft seen by the heating equipment.
But on one point I don't agree: the purpose of the damper is not to give cleanout access to the flue; anyone who claims to have cleaned a heating system just through the damper has not done a proper nor adequate job.
Typically when we see a system with no barometric damper we infer that there was a chimney with marginal or inadequate draft.
I have a oil furnace with direct-venting through a vertical wall. My barometric damper is always open and allows cold outside air to enter the basement when the furnace is not running. Is this proper? We have had the service techs of two different companies here and when I mentioned it to them, neither of them made any comment. Can I replace this part myself, or do I need to find still another furnace repair company? - Paul Hallisey<paul.e.hallisey@gm 1/15/2013
At some buildings we see the draft regulator forced open when the equipment is not operating because of the stack effects of the chimney and the entry of air into the utility room. If the open damper is costing in lost building heat you may want to install an automatic flue vent damper that shuts down when the system has turned off and opens up when the heating system turns on.
You wouldn't eliminate the draft regulator. Instead, an automatic vent damper is added to the flue to shut it down when the equipment is not operating. Search InspectApedia for automatic flue vent dampers to read details.
I an experienced plumber/pipefitter who is experiencing some puzzling problems with my boiler. I had my Weil McLain GTO 5 boiler, QB 180 burner cleaned and serviced about a month ago. At that time it was running fine. The night after it was cleaned the burner started locking out a few times a day and night. I have tried to get the one who serviced it to come back but with no success.
I then started to apply the limited knowledge of burners I have and I noticed a slight waining sounds come from the burner just before it would spit and sputter, then lock out. I bought a new oil pump, insatlled it, and I am still experiencing the same problem. Only now it will run fine for 5 minutes and then the flame will blow out and then come back, with that happening just before the burner shuts off, sometimes without locking out the control
. I have adjusted the gap and air flow to the specs of my boiler. I will say the nozzle is a 1.10 and my model calls for a 1.20 but the help at the supply house said that wouldnt matter. My next step is to replace the primary control or opening up the fan motor to inspect that. Anyone with some insight please share! - Ryan Darvalics 1/18/2013
Ryan, I don't want to guess at what's wrong with your heater with so little information, but
"started locking out a few times a day and night" certainly indicates an improper operating condition; The heating company should send an experienced technician to diagnose and fix the problem that your note suggests was left by the last fellow.
The nozzle size change you cite is withing spec range, might pertain to an upped oil pressure setting, and would not explain oil burner going off on safety-lockout. A lockout occurs when the flame does not ignite properly - a problem that can be caused by a variety of issues.
Changing the fuel unit for a new one before diagnosing the problem can be a costly and unnecessary step. For example, a leak in the oil piping, a clogged filter, even a simple clogged fuel unit strainer can cause ignition problems - not reasons to change the whole fuel unit.
You can read further about oil burner troubleshooting at OIL BURNER INSPECTION & REPAIR and at OIL BURNER NOISE SMOKE ODORS but I would stop shotgunning, installing new parts, before we have an accurate diagnosis of what's wrong.
(Mar 9, 2014) Anonymous said:
i have a jungers oil furnace - gravity feed oil. I need to buy a barometric damper for 4-5 inch pipe
To protect the confidence of our readers, InspectApedia does not sell any product or service.
But it's easy to buy a draft regulator in the common size ranges including yours. Just stop by your local HVAC supplier or building supply store with the diameter of your flue vent connector in hand.
(Sept 5, 2014) Anonymous said:
Thanks for the article. Informative.
(Dec 14, 2014) Bill said:
I have a Alaska channing 111. My barometric damper is 6 in then [the flue vent connector goes to 8 in to connect ] to massonary chimney.
It seems I need two dampers. I installed a manual damper to help
My question is can I put 2 baro dampers in the same flue to control proper draft
The Alaska Channing III is a coal stove (shown at left) designed to burn rice coal and with a BTUh output of 5,000 to 85,000 BTUh. That heat output capacity is controlled in part by controlling the fire rate by controllinb combustion air.I suspect that you have a problem with your stove's doors (not closed or sealed) or installation. Details and a thorough answer for your question are now found at COALSTOVE DRAFT CONTROL.
(Jan 13, 2015) Anonymous said:
should draft control be open with a good flow of air going up the chimney when oil furnance is off
Anon, what you describe is normal, may be wasting heat, and can be prevented by an automatic flue vent damper add-on device that closes the flue by an electrically operated damper when the burner is off.
2 Feb 2015 Amy said:
I just found my draft control flap laying on the floor, it broke off on its own. Is this a major issue until I can get a replacement? Should I worry about Carbon monoxide? I held my hand near the opening and it still felt like it was pulling air in to exhaust out.
Amy you want to repair or replace the draft regulator promptly. Presuming yours is oil fired equipment the risk is usually less of carbon monoxide and more of improper draft or inadequate draft if the flue is wide open because of loss of the damper flap. In turn that can cause poor oil burner operation and ultimately could lead to loss of heat or even an oil burner puff-back explosion. (see that article in More Reading above).
The part itself is inexpensive even if the whole assembly has to be replaced.
But more often restoring the control flap is close to trivial. Take a look at the photos and discussion in the article above and you'll see details of the few parts that make up the damper and its flapper. Most likely you can simply replace the flapper door or use a 4d finishing nail or piece of wire to makeshift a temporary (if lost) hinge pin to put the door back in place until your heating company can come by to make a proper repair. As long as the door is replaced, secured, and moves freely it should work close to as before.
Use our CONTACT US link at page top or bottom to send me some photos and I can comment further.
(July 4, 2015) Bruce Rowe said:
So I just purchased a new field 6 inch barometric damper. The supplier said my old one was installed improperly. I had about 18 inches of stove pipe off the top of my furnace With a tee going into another piece of 6 inch stove pipe into the chimney. The old damper was installed in the opposite end of the tee. With the counter weight set for vertical operation. I replaced the tee with an 90 degree elbow and put the new damper in a tee between the elbow and the chimney. I was not aware of the two positions for the counter weight.
As stated in your article the counterweight comes fatory installed for vertical operation. I just got a serious burn off the stove pipe, which caused me to look into Why is the flue pipe so hot. I changed the counterweight now I need to get it adjusted properly. My supplier said he didn't realize these should be so touchy and said I probably have something else wrong with my furnace.
But after changing the position of the counterweight for horizontal operation. My flue pipe is considerably less hot. I know I need to get someone here to adjust everything properly. But does the Horizontal vs Vertical Setting of the counter weight make that much difference? I only have about 24 inches total of horizontal flu. I have about 32 ft of vertical chimney.
First off, sorry to read of the burn. For sure flue vent pipes can be very hot and can burn someone. Don't do that again.
I don't have a clear understanding of the installation, and I agree you need an onsite service technician to review this installation. The concerns are not just burns but death from carbon monoxide poisoning or overheating equipment and a building fire. IE such an installation is unsafe.
An onsite tech will measure draft in the breech, draft over the fire, and also system operating tempeature. Those are not things that you can properly nor safely adjust without the proper test equipment. Sorry.
It's your replacement of a tee with an elbow that is confusing to me - it's not an arrangement I can picture and I worry it's not following the manufacturer's specs.
(Jan 26, 2016) jeff said:
have a gas boilers 4 cga8 boilers are sooting up gas psi at manifold is good flue is stepped down for draft. burner flames are high licking the boiler. Would a barmitict damper be better to use than the existing draft hood
Watch out: I would turn off the heating system immediately. I know this may sound glib, but sooting gas boilers are very likely to produce fatal carbon monoxide poisoning. Call for help from a trained service technician. Don't try to solve the problem by simply installing another draft regulating device.
(Apr 3, 2016) Doug said:
I have a NG forced air furnace and a NG fireplace in my 2004 built home in the WNY area. I have a independent draft regulator venting into my basement. I do not understand why I need this? My understanding at the time by the home builder was that he builds "airtight" homes and that's why I need it.
Fact is my house is far from "airtight", and this vent is on the windy side of my home and this vent allows a steady stream of cold air into my basement making it quite cold threw the winter months. I am planning a basement finishing project know and want to eliminate the source of the cold air. Just curious what the ramifications may be. I do have photos, but this comment section doesn't seem to allow :(
If a gas-fired heating appliance does not have adequate combustion air it can produce fatal levels of carbon monoxide. The draft-hood on your natural gas furnace regulates the draft but does not provide combustion air to the furnace. Your heating service tech can check your system operation, location, burner adjustment, flue draft, size of the area where it's located, and similar specs and can compare those with the manufacturer's requirements to be sure there is adequate combustion air. I agree that if the area where the furnace is located is big enough or receives enough natural ventilation and combustion air, you may not need the extra air source.
See inspectapedia.com/heat/Combustion_Air_Requirements.php found by searching InspectApedia.com for COMBUSTION AIR REQUIREMENTS
You are welcome to send us photos via the page bottom CONTACT link.
(Apr 6, 2016) Doug said:
Thanks for the valuable information. I did send my photos per your link for your edification.
Watch out: This looks like a home-made jury-rigged combustion air inlet for heating equipment. It looks as if there is a dryer vent, flex duct, and a barometric damper used (backwards) - I can't understand how that setup would work. Usually a Field Controls draft regulator like the one in your photos vents OUT through its opening face, not in to the room where your set-up is shown.
You'll want to see these two articles
One can't guess at what your equipment needs from just those photos (the articles explain the basics of how to figure that out).
But it seems unlikely that a clothes dryer vent sized intake provides a meaningful amount of combustion air anyway.
If your heating appliances do not have enough combustion air without ducting in outdoor air, there are systems that will duct the air right to each burner where it's needed, avoiding creating a chilly draft across the floor of the same spaces.
Watch out: inadequate combustion air supply to gas fired heating appliances risks fatal carbon monoxide poisoning.
(Aug 9, 2016) Brett said:
I realize a barometric damper is required on the flue of oil fired furnaces but are they required on all oil equipment specifically water heaters
Yes Brett. The bottom line is this: it is impossible to properly and fully tune and adjust a natural-draft oil fired heating appliance of any sort without a barometric damper, because you are giving up the ability to regulate the draft as building and weather conditions vary. That's why a fancy name for barometric damper is "draft regulator". If you cannot regulate the draft that means that sometimes the draft is too weak (sooty flame, incomplete combustion, clogged-up oil burner components) while other times the draft is too strong (increasing operating and fuel cost by sending wasted heat up the chimney).
That's also why "sharing" a barometric damper on a shared oil flue vent connector that connects both an oil fired heating boiler or furnace and an oil-fired water heater to the same chimney won't work. If the tech sets the draft regulator for proper boiler or furnace draft the water heater suffers, and vice versa.
An exception is that power-vented equipment may not use a conventional barometric damper.
2016/09/22 Rafael said:
Where does the adjustable weight goes (up or down) on a horizontal damper installation?
Great question Rafael; the weight may go up or down depending on the specific damper model. What's critical is that the axis of movement is horizontal and of course that the weight is properly adjusted so that the draft is correct.
Other draft controls whose hinge is in the dead center of the opening may work equally well with the weight above or below the hinge.
So tell me the brand and model barometric damper and we can (either of us) look at the manufacturer's installation instructions.
Draft Regulators for oil fired heaters: Details about draft control on oil fired heating systems (such as the oil fired heater shown in the photo above), including furnaces or boilers, are discussed in this article just below.
Draft Regulators for gas fired heaters: Details about draft control for gas fired heating systems, including furnaces or boilers, are discussed separately at at DRAFT HOOD, GAS HEATER for gas fired equipment.
Continue reading at DRAFT REGULATOR, DAMPER, BOOSTER or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
Or continue reading at DRAFT REGULATOR SOOT INSPECTION
Or see CHIMNEY INSPECTION DIAGNOSIS REPAIR - home
Or see CARBON MONOXIDE - CO
Or see COMBUSTION AIR REQUIREMENTS
Or see DRAFT HOOD, GAS HEATER for draft regulation on gas fired heating equipment.
Or see DAMPERS & DRAFT REGULATOR TYPES for a complete list that includes draft regulation on wood, coal, oil, and combination wood-oil fueled boiler and furnaces.
Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia
Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
Please see the FAQs in the article above.
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Search the InspectApedia website