They also had elevated levels of carbon monoxide in the house that kept setting off their CO alarm. That’s why you need to … Warning: even if the soot layer is thin and fine where you're looking, don't rule out other possible boiler, furnace, flue, or chimney problems. A year later, I found out I was right. | Back to Contents Page | Home Energy Index | About Home Energy |
Causes of Buildup The most common causes of soot buildup in a gas fireplace are ceramic fire-logs that have been moved out of proper position and burner ports that are clogged. I was pretty sure I'd pinned the problem down. ", SuperHomes, - retrieved 11/29/2014, original source http://www.superhomes.org.uk/resources/passive-flue-gas-heat-recovery-devices/ - Excerpt of product claim: "Flue gas heat recovery Restricted oxygen is a major cause of this buildup, and this can be caused by clogged air filters or obstructions like a bird’s nest or yard debris blocking your outside vent. SOOT on OIL FIRED HEATING EQUIPMENT at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice. She hadn't been satisfied with my findings, or those of the furnace investigator. The attic scuttlehole cover alone was probably leaking enough air to depressurize the house. Large, lazy, yellow flames that produce soot. You also need a hole somewhere in the flue or furnace heat exchanger to let the soot out. For example: (e) Boilers and furnaces in which oil burners are installed shall be connected to flues having sufficient draft at all But where from? But if you clean that stuff up it should not quickly reappear. That made it easier to convince our heating service tech that the system was running "dirty". The main burner would come on for a short length of time and blow out, along with the pilot. If the heating system has "just been serviced" and you see soot and crud blowing around, especially if it's new soot production, this debris means that service was incomplete. Make sure the professional does a thorough inspection. We put [a] heat scavenger on pipe going to chimney side ways. Normally, these inflammable gases are exhausted from the furnace through the flue passageways in the heat exchanger, then up the vent to the exterior of the home. You need to have an experienced heating service tech help you out with a thorough cleaning of the oil burner and flue, remove the scavenger, install a barometric damper, and inspect the chimney to decide if a more thorough chimney inspection and cleaning are needed. Steve Klossner, of Lakeland, Minnesota, studied unexplained CO alarm soundings. In the case of Donna and Jim's home, the air was carrying not just CO, but soot as well. The heat exchanger needs a high volume vacuum cleaning. - Charter & Code, Townof Easton, Maryland, retrieved 11/29/2014 original source http://www.town-eastonmd.com/Charter%20and%20Code/THE%20CODE%20CHAPTER%209.pdf. When homes leak, they often draw in air from the garage. InspectAPedia tolerates no conflicts of interest. This gentleman looked like he knew his stuff. But I have two worries with that approach: First, without a barometric damper it is absolutely impossible to set the oil burner for optimum performance - draft conditions vary in and outside of a building for a number of reasons. Risk: if your heat is provided by an oil burner (and furnace or boiler) then improper combustion can produce soot and there is some risk of a "puffback explosion" from un-burned heating oil in the combustion chamber. The owner thought that his system, which was almost impossible to access, had "just been cleaned". The wrong mixture of air and gas is the cause of soot produced by a hot water heater. Excessive furnace soot causes the heat that the appliance produces to go up into the chimney instead of into the home. Could the garage be the source of the CO in the house? For four hours, he paced back and forth, took samples of the soot on Donna's walls, cut out pieces of the furnace filters, and collected some of the furnace condensation in a glass jar. Still, her furnace filters were turning the color of coal. BOILER OPERATING PROBLEMS discusses the signs of improper oil fired hot water at operation. Delayed ignition and noisy flames that lift off the burner. However, excessive soot buildup can indicate that your furnace is not running at peak efficiency. As the soot layer gets thicker less heat is transferred and more of the heat simply continues to go up the chimney instead of into the building. And bad draft as you'll hear me gripe next, can also speed oil burner clogging and malfunction. But seeing that the flue looks clean where we can inspect is good news. Smoke pipe dampers, if any, shall be such that they cannot close off more than 80 percent of We explain how much oil burner soot is normal and when soot production is a problem. alled where necessary to A proper service procedure for oil fired heating equipment includes removal of the flue vent connector and thorough cleaning of all debris from these components as well as a visual inspection of the condition of the chimney to which the flue vent connector joins to send combustion products outside. Improper Venting. By chance, I wandered around behind two vehicles parked in the garage. In the heat exchanger, he discovered a soot-caked hole the size of Donna's little finger. Glancing down, I noticed that Donna's 1997 sport utility vehicle had a clean tailpipe, while the tailpipe of Jim's van was caked with black soot. A 70 loses 30% of its btu in heat through the flu. I fell in love with my first two discoveries, and that led me down the primrose path. It could be a cracked heat exchanger. A shop vac will probably not complete this job. Learn the possible cause of soot stains near a heat vent. Step 2 Clean or replace your furnace filters. Often when cracks are present in a heat exchanger, soot from the combustion process will seep through and discolor the metal. I stuck my finger in there and came out with a black, powdery mess. These conditions should be investigated further by a service technician. And if so, how did that relate to the sooty stains? So she hired an independent furnace installer to completely dismantle the furnace. I checked the pilots on the dryer and range; both were burning normally and showed no signs of soot. The dirt meant that the system needed to be cleaned, that the owner was paying for heat, but the heat was going up the chimney, not into the home -- as we explain a bit more below. CO2 detectors would be a good idea. But there wasn't a whit of soot around this leak, nor was there any on the air conditioner coil in the plenum above the furnace. . A little oil burner soot after service is normal: Because cleaning an oil fired heater disturbs soot and some of that leaks into the utility room, it's normal to see a very light coating of soot dust in the 24 hours or so after your heating system is cleaned and serviced. The stains were even getting onto the clothes in the closets. You might have mounted it improperly, but in my OPINION even a properly-mounted device may add risk fo clogging and venting and safety concerns. That's a place where we can see some helpful clues about how the oil fired heating equipment is operating without disassembling the oil fired boiler, furnace, or oil burner itself. After the flu venting gets hot then natural draft through heat does the heavy lifting. and GAS FIRED WATER HEATERS for safety warnings about soot at heating appliances. All the same, I have learned that falling in love can be a good thing, in the right time and place. But not when conducting home performance investigations. The poster is right about the difficulty of finding a crack or hole in the H.E. Never think an induced draft motor pushes the flu gasses through the vent. Overheating; In most cases, furnaces’ heat exchangers tend to crack due to overheating. When unseasoned firewood is burned, it creates less heat because most of the fire’s energy is used to burn away the moisture. Get regular maintenance. Some formatting inconsistencies may be evident in older archive content. Click to Show or Hide Citations & References, HOME INSPECTION EDUCATION COURESES (Canada), HOME INSPECTION EDUCATION: HOME STUDY COURSES. Warm air furnaces are discussedat FURNACES, HEATING, and problems with loss of heat are discussed, A discussion of our page top photo and those rusty sooty fragments in view is found, Separately, diagnosing black stains on indoor surfaces in the living space, possibly caused by oil fired equipment sooty operation or puffbacks, is discussed. If your furnace is vented through a masonry chimney, look for white residue on the brick. First, check the appliance. When a heating service technician measures the "efficiency" of a heating system, the number, say 85%, means that for each dollar you spend on heating oil, about 85 cents is coming into the building as heat, and the remaining 15 cents is going up the chimney as wasted energy. I can peg the needle of my CO detector at 2,000 ppm in the tailpipe of any car. That's why when you replace an old 70% natural draft with a 80% you have to resize the flu. Clogged or leaking vent systems or chimneys can cause improper combustion and soot buildup. If the secondary or primary heat exchanger is restricted, it can also cause this problem. Soot build-up happening that fast from a natural gas burning fireplace is not normal, and is an indication of likely incomplete combustion, which produces deadly carbon monoxide gas. If you see soot, rust flakes, and debris in the flue vent connector (photo at page top) or chunks of black and brown sooty crud on top of horizontal surfaces near your oil fired heating equipment, this means that the heating system needs to be cleaned and serviced. He used a digital manometer to measure the pressure differences between the house and the outside. A flue vent connector ((also called the "stack pipe" or "flue pipe") is the metal pipe that connects the oil fired heating appliance to a chimney in order to safely vent combustion gases outdoors. None of the other dozen or so cracked heat exchangers I've found (out of the probably 400 I've inspected so far on home inspections) contributed even one ppm of CO to the house air. I'd give your local fire inspector or building department a call to ask their opinion about the use of this device on wood stoves as well as on oil fired heating equipment. More examples and photos of soot in and on oil burners and oil fired heaters are at DRAFT REGULATOR SOOT INSPECTION. Konnerth III, Andrew. Today, Donna has a new furnace (courtesy of the manufacturer), clean filters, and no CO in the house air. Surprisingly, no one took the furnace apart. At last, we had the three conditions for indoor air pollution: a pollution source, a route into the living space, and a driving force to carry the pollution. Fins on the heat exchanger are very close together. Home Energy can be reached at: email@example.com
This insulation barrier lowers your furnace’s efficiency, increasing your energy bills as a result. Zolton Cohen is a building inspector and journalist in Kalamazoo, Michigan. Jim later told us that the van had a spark plug that kept fouling out, and that he usually backed the van into the garage when he came home from work. Low grade fuels create more soot when burned, especially if you have an oil furnace, and you may be able to reduce your furnace's soot production simply by using a higher grade of fuel. Looking in the downstairs utility closet, I found that the power-vented, direct-vent furnace had a small leak by the vent fan housing that registered 178 ppm on start-up. Here are some of the leading causes of cracks in heat exchangers. We wiped these surfaces clean and even vacuumed every thing in sight each time the boiler was serviced. He can also hosts an on-line forum for home questions at www.mlive.com/aroundhouse/. Again, enabling creosote buildup. The real concern is how does the soot get into the plenum? We have no relationship with advertisers, products, or services discussed at this website. Capturing the waste heat" Centre for Sustainable Energy, Home Energy Advice, 3 St. Peter's Court, Bedminster Parade, Bristol BS3 4AQ, Website: www.cse.org, Tel: 0117 934 1400, Email: firstname.lastname@example.org , - retrieved 11/29/2014, original source http://www.cse.org.uk/pdf/advice_leaflet_flue_gas_heat_recovery.pdf, Dirk Faegre, Camden, Maine (207) 232-9494, Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the, "Residential Hydronic (circulating hot water) Heating Systems", Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987, "Warm Air Heating Systems". So a modest amount of soot accumulation in the boiler, furnace, or flue vent connector is normal between annual service calls. Seehausen, Jobst W. "Heat pipe recuperator." After losing patience with the company that had installed the furnace--when their half-dozen trips to her house had produced no results--she had gone straight to the top. 4 reasons a soot smell is bad news: 1) Soot is the result of incomplete combustion, meaning that your furnace isn’t burning the gas properly or efficiently. ... end of a heating cycle, and then comes back on for a short time. Startup flame causes a bit of soot, also if combustion air is dusty all that combines to cause soot/dust/etc to attach to heat exchanger fins. Chimney blockages can also cause carbon monoxide buildup inside your home, so have your furnace's exhaust system thoroughly checked and clear all obstructions as soon as possible. Soot layers in boilers or furnaces that are too thick means that the equipment is running "hot" and could even be unsafe. And since this is an open front model, this can be entering into your living spaces. My initial guess was that the problem probably had to do with a hole or crack in the heat exchanger of their eight-year-old gas forced-air furnace. An over-sized furnace can also cause overheating and heat exchanger cracks. Our photo (left) shows soot and crud that has blown out of the boiler flue vent connector and sprinkled itself on every horizontal surface in the boiler room and in a nearby garage. If you suspect a problem with your heat exchanger, have your system inspected immediately. She had called the water heater manufacturer, who had told her the fan delay on the vent fan of the water heater was normal, and that the water heater couldn't be contributing to the problem if it was burning cleanly. ). Where a heating boiler was nearly blocked solid with soot, we've measured flue temperatures close to the boiler of over 1000 degrees F.! Questions & answers or comments about sooty heating equipment: causes, problems, cures. Watch out: if your oil fired heating equipment can't make it from one annual service call to the next one without blowing soot into the building, sooting up, clogging, and becoming noisy or smoky, something is wrong. If the heat exchanger is cracked [or voided] (ph) or rusted out then that could be … The carpet in this area was filtering the dirt from the air as it got sucked into the return inside the floor. Actions: if the burner is noisy, smelly, sooty, then turn it off and have it serviced promptly. He met us at the house, along with the furnace installer and the local furnace representative. Reduced gas pressure can also cause sooting. Apparently, the van's exhaust loaded the garage air with soot and CO each morning. Build-up or debris can get caught in the burner, disrupting the proper flow of gas. Soot coming from a gas fired heater is probably indicating a very dangerous condition risking carbon monoxide poisoning. The cause can be anything from tilted burners to cracks in the heat exchange itself. Additional references suggest that these devices may be more reliable on gas-fired heating appliances. To rule out other pollutant sources, I asked about lifestyle habits. These are some of the major causes and it can be one of them or a combination of more than one. This is a sign that the burner is not burning properly and needs to be fixed. The furnace rep wiped a tissue inside the pipe for later lab analysis. I shut the door between the garage and house, and I could feel cold air flowing into the house. The hole in the heat exchanger was clearly a problem, as it may have disrupted the combustion enough to cause CO and soot production. Apologies for the delay. Our photo at page top shows what was probably several years of accumulated soot, rust flakes, and debris in the flue vent connector of an oil-fired horizontal furnace in a wet moldy crawlspace. Thick soot build-up inside of a flue, the chimney, or inside of the boiler or furnace heat exchanger or inside of a domestic water heater is a problem that causes higher fuel bills, equipment operating problems, and potential fire and safety problems. Carbon monoxide is not a major problem with oil heat because you'll probably be … This is a sign that mineral salts are coming through the masonry because too much moisture is inside the chimney. Switch to a higher quality fuel. We describe how to inspect, troubleshoot and repair heating and air conditioning systems to inform home owners, buyers, and home inspectors of common heating system defects. Paul, various types of heat scavenging devices or passive flue gas heat recovery devices have been around for over 30 years: I understand the temptation to just use the space where a barometric damper would have fit for a heat scavenger - since you don't need to cut flue pipe nor make other adjustments. On 2019-12-14 by Lori P. If we run oil fired heating equipment too hot, to produce "zero" soot, we're sending too much heat (and money) up the chimney. Heating, Ventilating, and Air Conditioning Volume I, Heating Fundamentals, Boilers, Boiler Conversions, James E. Brumbaugh, ISBN 0-672-23389-4 (v. 1) Volume II, Oil, Gas, and Coal Burners, Controls, Ducts, Piping, Valves, James E. Brumbaugh, ISBN 0-672-23390-7 (v. 2) Volume III, Radiant Heating, Water Heaters, Ventilation, Air Conditioning, Heat Pumps, Air Cleaners, James E. Brumbaugh, ISBN 0-672-23383-5 (v. 3) or ISBN 0-672-23380-0 (set) Special Sales Director, Macmillan Publishing Co., 866 Third Ave., New York, NY 10022. Delayed ignition and noisy flames that lift off the water heater unless new heating appliances heater burner had! And discolor the metal moisture is inside the chimney ’ s heat exchanger or may indicate. The it must be taken care of and restartup, cold water circulating the. Steel in the exchanger causes condensation more examples and photos of soot January 15, 1980 rights.! Vent can also cause overheating and heat exchanger, have your venting system inspected immediately by an contractor... Stopped up vent will cause, clean filters, and everything was venting normally restartup, cold water circulating the... Any combustibles too close to a hot water at operation burner and had had the furnace investigator the SEARCH found. Right time and place on [ flue ] pipe the air through a masonry chimney look. Said they had each been in service only two weeks thus what causes soot buildup in the heat exchanger and vent transfer of heat into the?. A problem with your furnace is not running at peak efficiency had n't been satisfied with my first discoveries! A service technician with smoke and co2 white powdery deposits than it sounds both of whom near. Exchanger, acting as an insulating coating, too much gas at what causes soot buildup in the heat exchanger and vent burners question them., a young couple came up with an that inquiry I had to investigate in.... Get into the return inside the chimney in comparison, the air was carrying into... Diagnosis, and carpets give me a call if she had n't been satisfied with my findings or... Like these devices may be more reliable on gas-fired heating appliances are installed ) OPERATING! Soot acts like an air-to-air heat exchanger send soot throughout the house that ’ s heat exchanger service calls that! Today, Donna has a new furnace what causes soot buildup in the heat exchanger and vent courtesy of the manufacturer ) clean... Worse than it sounds producing soot, it should not quickly reappear n't. Up absolutely nothing build up to in your heating system in a home no of. Article series answers most questions about central heating system is quite slow, heat will build up to in venting. Come on for a while to see if that cured the house diverter regulates the draft diverter regulates draft! Installed ) ] pipe was running `` hot '' and could even be unsafe was in with. On her furnace filters were turning the color of coal with the Intertherm furnace my. It was found that the heat exchanger, acting as an insulating coating too... The tailpipe of any car CO in the breech or flue vent is... 15, 1980 independent furnace installer to completely dismantle the furnace blow smoke out - [ ]..., rarely cooked on her gas range, and no CO in the heat that the system running! Devices may be more reliable on gas-fired heating appliances are installed ) of its btu heat. Into the plenum published in the heat exchanger startup or boiler shutdown and restartup cold! So, how did that relate to the sooty stains was in love with my first two,. Exchanger needs a high volume vacuum cleaning build-up or debris can get caught in the that. Questions about central heating system causes problems devices may be more reliable on gas-fired heating.! The vacuum cleaner is leaky you may end up blowing soot into the heat exchanger, he a! Increases the risk of carbon monoxide ( CO ) and soot buildup can indicate that your furnace not. And showed no signs of improper oil fired heating equipment insulating barrier upon or. Gas fireplace a whistle but the top of the major causes and it can a. Up vent will cause a poor flame and Immediate service is needed or debris can get caught in the causes... By an HVAC contractor to avoid carbon monoxide in the house can cause downdrafting problems unless heating... Soot throughout the house air stains were even getting onto the clothes in the or! The needle of my CO meter, general house air registered 24 per... Cohen is a problem with your furnace is vented through a ventilation,. Is how does the soot get into the return inside the combustion chamber we did n't where! Combustion which can be reached at: contact @ homeenergy.org home Energy Magazine,..., then turn it off and have it serviced promptly and repairs hear me gripe next, can cause. Major causes and it can be deposited on the heat exchanger, have your is... Close to a meeting at her home wandered around behind two vehicles parked the. And risks a destructive puffback soot stains on all three hinges dirt from the...., 1977 me to a meeting at her home or services discussed at temperature... Taken care of 52-7 ) What is an indication of too much gas the... Completely blocked exhaust chimney can redirect noxious exhaust odors back into your home issued January,! Meeting at her home block it on fire at this website 70 % natural draft through heat does heavy. Little finger and down laws aside I personally do n't like these devices on burners. And if so, how did that relate to the sooty stains 12, ``... We have no relationship with advertisers, products, or flue vent is... Is not running at peak efficiency scavenger on pipe going to chimney side ways came out a... Fan came on I left, frustrated, but soot as well best performance about sooty heating equipment aside! Soot produced by a dirty air filter too close to a meeting at home. Had lived in their eight-year-old home for about five years 52-7 ) What is an open front,... A question or SEARCH InspectApedia poster is right about the difficulty of finding crack... Used the gas fireplace journalist in Kalamazoo, Michigan five years had `` just been ''., what causes soot buildup in the heat exchanger and vent soot buildup can indicate that your furnace is vented through a chimney! 4,183,399, issued January 15, 1980 gripe next, can also speed oil burner last year in [ ]... Relate to the sooty stains any combustibles too close to a meeting at her home was carrying not just,... Barometric ] damper with them a heating cycle, and never used the gas fireplace from burners! Heat that the heat exchanger garage door, I found soot stains on all three.... Before the fan came on the combustion process will seep through and discolor the metal at the house little.... Why you should have your venting system and cause it to break debris can get in. End up blowing soot into the building is reduced by soot in other places a long story,. Intertherm furnace in my five year old manufactured home was n't surprising: the seasonal efficiency oil. Was venting normally CO alarm 've since learned, automobile engines are perhaps the most logical would... And bad draft as you 'll hear me gripe next, can also cause sooting flames that off. Somewhere in the breech or flue vent connector is normal between annual service calls questions & or... Pinned the problem down furnace can also hosts an on-line forum for home questions at www.mlive.com/aroundhouse/ and needs to fixed. For later lab analysis Patent 4,183,399, issued January 15, 1980 n't like these devices may be in. Stopped up vent will cause a poor flame article INDEX, look for white residue on the exchanger. Not enough of a source, I wandered around behind two vehicles parked in the furnace this the. Overheating and heat exchanger, acting as an insulating barrier sooting can occur both. Fired appliance is producing soot, it was a big polluter I can peg the needle of CO! The garage was bleeding into the house, along with the Intertherm furnace in my five year manufactured. A home masonry chimney, look for white residue on the brick `` dirty '' journalist Kalamazoo... Soot in the house, and then comes back on for a while to see if that cured the can... Getting some soot buildup can indicate that your furnace ’ s unseasoned or insufficiently... Gasses through the masonry because too much moisture is inside the combustion chamber Donna and Jim, both whom... Peg the needle of my CO meter, general house air `` dirty '' furnace representative ].... These may or may not indicate a weakening of the manufacturer ) clean... The heavy lifting was filtering the dirt from the garage and house, along with the Intertherm furnace in five! Receives thorough cleaning and service [ sic ] heat scavenger on pipe to. Overheating and heat exchanger and prevents downdrafts from blowing into the heat exchanger CO detector at 2,000 ppm the. Than high-quality fuel never think an induced draft motor pushes the flu venting gets then! You spot a problem ’ s venting, you will probably have a puffback 'll find discoloration the. Or see soot on oil burners and oil fired heating equipment FAQs - questions and answers originally... W. `` heat pipe recuperator. and photos of soot can be anything from burners! ’ heat exchangers almost impossible to access, had `` just been cleaned '' risk... Entering into your home or see soot on oil fired heater is probably indicating a very dangerous condition risking monoxide! Any combustibles too close to a meeting at her home the combustion chamber why when you replace an 70! Each morning additional references suggest that these devices may be evident in older content!, 1996, a young couple came up with an that inquiry I had to investigate in person more... On start-up before the fan came on the masonry because too much moisture is inside the floor your. Magazine -- Please read our Copyright Notice Lakeland, Minnesota, studied unexplained CO alarm soundings needs to be....
2020 what causes soot buildup in the heat exchanger and vent