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AIR CONDITIONING & HEAT PUMP SYSTEMS
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DIAGNOSE & FIX HEATING PROBLEMS-BOILER
DIAGNOSE & FIX HEATING PROBLEMS-FURNACE
DUCT SYSTEM & DUCT DEFECTS
GAS LP & NATURAL GAS SAFETY HAZARDS
GEOTHERMAL HEATING SYSTEMS
HEAT PUMPS, DIAGNOSIS, REPAIR
HEATING COST SAVINGS METHODS
HEATING OIL TANKS
HEATING SYSTEM TYPES
MANUALS & PARTS GUIDES - HVAC
NOISE, HEATING SYSTEMS
ODORS FROM HEATING SYSTEMS
OIL SPILL CLEANUP / PREVENTION
SOLAR HEATING SYSTEM DESIGNS
STEAM HEATING SYSTEMS
THERMOSTATS, HEATING / COOLING
VIDEO GUIDES: HEATING SYSTEMS
WOOD-OIL COMBINATION HEATERS
WOOD STOVE OPERATION & SAFETY
Oil burner noise, odor, performance or smoke troubleshooting:
Some oil burner noises are normal, others indicate trouble - we explain the difference.
We also explain how to recognize & diagnose the cause of oil fired heating boiler noises, leaks, odors, or soot and smoke.
We describe just about any noise that you might hear at or near an oil burner, where it comes from, what it means, and what needs to be done about it.
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What Oil Fired Heating System Noises are Normal and What are the Noise Sources?
Some heating system and heating oil burner noises are considered normal. These include noises coming from the following items:
The sketch above is provided courtesy of Carson Dunlop Associates.
What oil fired heating system noises are abnormal and may indicate an operating problem or an unsafe condition?
Noises & soot buildup can lead to a potentially dangerous puffback which can damage the heating equipment and blow soot and smoke throughout the building. An experienced heating service technician may recognize the following diagnostic list of heating system or oil burner noises as well as perhaps other signs of trouble:
What can we do to reduce heating system operating noises?
Heating equipment located well out of occupied space, in an unoccupied basement, for example, are not usually a source of noise complaints in a building, though there are a few exceptions for which we have suggestions.
Articles at this website 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.
Continue reading at OIL BURNER NOZZLE & ELECTRODES or select a topic from the More Reading links shown below.
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Frequently Asked Questions (FAQs)
Question: Oil burner noise: Cause & cure for heating boiler "snap, crackle, & popping" noises: antifreeze acidified & debris in the system: flush out needed
This may not mean much in the grand scheme of things but I want to thank you for your site.
I am high in the Rockies and have had boiler issues the past year. My glycol had acidified and when the boiler was firing the “snap, crackle and popping” could be heard throughout the house so my plumber did a flush last winter.
All eight zones and the boiler were flushed through with a flush solution for several days, unfortunately they could not get the end caps off of the Teledyne boiler lines to brush out the heat exchanger of build up. In any event, I ended up finishing off the last winter with just fresh water in the system (did not add glycol after flushing, just removed the flush: lots of small particulate came out in the brown discharge) but I finished off the winter with heat in the house. Good thing, we had –30F temps at times.
Anyway, recently, rather than buy a new boiler, I had my guy do another flush, again two of the zones and the boiler did throw off particulate and they were dirty. Naturally, there was “green” in the discharge as I presume there was sloughing off of the inside wall of the copper lines that lead to the in floor heating tubes.
Anyway, we added glycol but man was I getting a banging still. So, with the help of your site I was able to figure out that the Proflo PFT12 expansion tank’s relationship to my Taco Hy-Vent air purge on top of the American Purge Valve and was able to see – as a layman – what was going on. I see that they are integral.
Now, I know to tap on the bottom of the expansion tank to make sure it’s not full to determine if if it’s bad. I also know how to use the Hy-vent to manually bleed off some air. I had a five second hiss yesterday and today only a two second hiss so I guess I am getting the air out.
Bottom line: your site showed the exact air purge and I was able to figure things out. Hopefully. Without your site I would be calling the plumber back all the time. Thanks for being there: no critique from me, just praise. regards, D.C., Breckenridge CO
Thank you for the very nice note D.C. We work hard to make InspectAPedia's information useful and accurate, so I'm really grateful to hear that it was useful to you. And questions or content suggestions are very welcome as they help me see where we need to do more work.
About the boiler flush-out, I'm not surprised that after a flushout and then use for a heating season, a second flush would be helpful. But after that, if the chemistry is proper in the system with an antifreeze installation, you ought not to have to keep doing flush outs as the same physical dose of water remains in the system - you're not introducing new water, minerals, crud. I guess the trouble is when it's difficult to complete a thorough cleaning.
Thanks for the details - I'll add a version of these comments to our section on diagnosing boiler noises.
my home oil boil (Warm-Flow bluebird 50/70) i put oil in and bled the boiler it ran for 1hr and again for 1hr later last night and it seems to have started up as normal this morning for 20min on son and now it wont, it only makes a humming noise like an electric board and clicks off loudly i hit the red rest button and same thing happens. no fan noise or low grumble as norm.
Reply: things to check
hi, we have a 9year old furnace, we had it inspected by an actual heating and cooling company when we moved in 2 years ago..he said the combustion ventilator motor is going(it rattles and hums) quite loud ,,,is it very dangerous to leave it for another year.... it freaks me out,.....will it explode, and or cause co poisoning...we have co detectors .....-katherine
Reply: things to check including the draft inducing blower assembly in the oil burner motor and its shaft and connectors
If by combustion ventilator motor you mean a motor that is used to induce a draft for the heater, I would replace it asap. The worry is that the motor may stop entirely and as luck will have it, at 2 AM on a holiday when you'll pay an arm and a leg to get the service tech out for an emergency no heat call.
I have a riello oil burner which makes a steady noise on and off when heating is on but all of a sudden the steady noise is much louder like a loud buzzing/vibrating noise...any ideas what it could be ? - Kerry
(Dec 24, 2012) Fred said:
My Aero burner was burning loud, with a lot of flapping on the chimney air valve, furnace was stored for 6 years before I installed it in my garage. I took the nozzle and electrodes out, cleaned them up and reassembled the gun with the electrodes exactly the way they were. I primed the pump and re-connected the wires properly, but the furnace does not fire now. It runs for a minute, then shuts off and turns the red light on. I can use a little help here
Reply: check these things:
Common sources of vibration or sources of buzzing vibrating sounds in or close to an oil burner include:
Let us know what you find, what we learn will help others.
Question: The furnace runs fine for a few days then we smell a choking burning odor
still did not answer the question, after servicing my furnace, change fuel filter clean furnace out and vacuum out the furnace, clean exhaust chimney,change nozzle, and give a good cleaning it runs fine, then within a couple of days and odor starts,like a choking burning odor that burns the nose ,what would cause this and how can I remedy this problem with calling a tech? and paying a bunch of money! - Bradly
Reply: things to check
Bradly I cannot diagnose the problem you describe just from your description.
Any of several errors could cause the problem you describe: improperly installed nozzle (leaking), air leaks in the oil piping, improper draft setting, improper electrode setting, etc. As some readers like iamhvac suggested, a cracked heat exchanger could be a source of odors as well, but you'd think that condition would be noticeable even immediately after service.
Watch out: If your heating system is smoking and producing odors it needs to be diagnosed and repaired by a trained service tech - you're not looking at just a filter change. And depending on the case, and the fuel, the conditions could be quite dangerous. iamhvac suggested "bradley sounds like a cracked heat exchanger causing combustion smoke to mix with your house air. time for a new furnace. call a pro get a free estimate." In our OPINION you don't want to jump the gun on this - get an accurate diagnosis before making a costly repair or system replacement.
Question: I smell heating oil odors when oil burner is running - is that OK or normal?
I can smell oil when the burner is on. Is this OK? - Ian
(Feb 10, 2013) Arthur Coppola said:
I had a new chamber lining installed.Upon completeing this when it fires i smell oil.The
(Dec 20, 2012) steveo said:
after cleaning the filter, the "screen" by the pump, this oil fired burner/furnace was still "smelling. After obtaining the proper size nozzle, I called the manuf. to get the correct settings (above,in front, apart) on electrodes, but that made it even worse! I modified the settings (further apart and further away from the nozzle,I reasoned, "further apart bigger spark" ,no?). That produced a much better result, yet now the smelling seems to be infrequent, off and on. What could be wrong? I have no efficiency tester btw did not think I would need one as long as I went by the manufact. specs. I am grateful for any suggestions.
Reply: No. Check for oil smells from the burner or from an oil leak or spill
Ian & Arthu & Steveo
if you smell heating oil when the burner is running there may be a leak or more likely the system is running dirty and out of adjustment, needing service. Just be sure you're not smelling an oil spill from a recent service.
Question: oil burner is producing black soot?
Just moved in to a rental and had to have oil delivered for heat. I just turned it on last night and woke up to the house being really foggy, I looked down stairs it didn't see any problems; however I blew my nose and it's nothing but black soot in my nose. It it because it's the first time coming on?? - Kim Haywood
Reply: proper oil burner servicing, cleaning, setup, and proper chimney draft are essential - don't blow soot into the home
Question: I swapped in the burner on my oil heater - now I get more odors but less soot
I have a new boiler sitting in my garage but could not afford to have it installed. When the motor on my old one stopped working we swapped it out with the new gun. The old gun was covered in sludge at the nozzle and caused many a soot puffing out. After putting the new one in I noticed more odors but no soot. the boiler is in an enclosed area 3 foot by 6 foot - steve H.
Reply: proper oil burner setup is required
Steve, it sounds as if it's time to ask a trained oil heat service tech to take a look at the system. Your burner swap may have left an underlying problem still in place, and also, frankly it is not possible to accurately set up and tune an oil burner by eye. Special equipment is needed to measure draft, CO2, smoke, and temperature while making those settings.
Question: oil burner bearing replacement
Can I fix an oil burner bearing myself - John 12/2/11
Probably not, John. Typically we replace the burner fuel unit or motor if it's bearing is shot. The squirrel cage blower fan assembly is also normally replaced as a unit.
Question: oil smell in basement when oil burner starts
I have an oil fired forced hot air system in my home. I had it cleaned and inspected about a month ago. It runs and heats fime most of the time. However I have noticed an oil smell in the basement when the oil burner kicks on and my attic fan runs at the same time(the attic fan has a humidistat). Is this becasue the attic fan causes a negative pressure in the house? Is this normal? Does my furnace need to be adjusted? Derrick - 12/9/11
Also see our notes in the article above and the Q&A's below about oil burner noise and smoke at startup;
Question: chemical odor and high pitched sound from boiler after chimney repairs
Hi, I just had the lining of my boiler flue redone. They took out the large pipe leading into the flue out of the wall and put the lining in. Later, after the boiler was turned back on we had a smell of some type of chemicalish odor. My boiler was also making a high pitched sound I have never heard coming from a box labeled honeywell on the large pipe connected to the flue.
This box has two silver pipes coming from it that connects to the main heating unit and a red button. We have turned off our boiler. The smell lingered for a long time. What is the box on the pipe called? What would be producing the burning smell (not like a fire smell at all- little chemically( not gas or oil smelling) The pipe was EXTREMELY hot to the touch. Thanks so much for any advice or labels! - Tania 1/2/12
Tania I'm sorry but I don't quite know what you've got installed - maybe an automatic vent damper that's not opening? Certainly, you should immediately ask your heating service company for help.
Question: Intermittent squealing sound when heat is run through two of 3 zones
I have a very old oil boiler that heats our hot water. It has 3 zones. When we run out heat on the 1st and 3rd floors, we hear an intermittent squealing like sound, but we never hear it when we run the heat on the middle floor. It never makes this sound when the boiler is running for our hot water. Any ideas what this problem or sound is? - Marie 1/4/12
Marie, this sounds like a problem with a circulator pump - maybe a bad circulator pump bearing; I'm betting your 3 zones each has an individual circulator and circulator relay; If I'm right you'll trace the sound to one or two circulators. Else I'm wrong and it's something else.
Question: oil burner starts & runs all night with reset button but won't re-start
My oil fired, warm air furnace exhibits the following mal-behavior:
It starts immediately upon pushing the red reset button; runs fine all day and into the night. It starts whenever the thermostat calls for heat during this period; it burns clean-no smoke, no unusual noises. It goes through its cycle and shuts down perfectly and provides good heat. This process continues on into the late night. Then, in the early hours of the morning, for some unknown reason it trips-off and stays off. It performs this cycle each and every day.
I have performed the following work on the furnace: Checked for leaks. Replaced the oil delivery line filter; replaced the pump strainer; replaced the furnace air filter; replaced the nozzle; and adjusted and reset the electrodes. Also I inspected and corrected electrical connections from the thermostat to the trip box. All appears in good shape. Start furnace and flame appears clean and well spread with no unusual sounds or smells.
The unusual behavior of this furnace was occurring before the work described above was accomplished and has been doing so for several years. Now, and after the work was accomplished, it still exhibits this unusual shut-off characteristic. The funny thing seems to be that the furnace never shuts off during the day time?? Any suggestions would be most appreciated. Thanks. - Tom 1/14/12
A oil fired heating system that goes off on reset but doesn't show signs of dirty fuel supply problems could have a bad cad cell sensor.
Question: intermittent choking sound from oil burner, then starts and runs. Stops, chokes, gasps.
My oil burner has been having an intermittent choking sound. It starts up fine. Runs smooth and even for five to seven minutes or so and then all of a sudden sounds like it is choking, gasping..... For about three minutes and then it switches back to running great, and runs fine and then does it again sometimes and sometimes it seems to be at the end of a heating cycle and choking and the system shuts off, only the shutdown does not require a restart....
My questions are
1 - what is the best way to install an outside air supply direct to the burner that will not chill out my house or allow in insects and rodents, so it has to be somehow controlled by the burner's need for combustion air, and
2 - how do I make sure my fuel lines are clean and not cruder up inside and impeding fuel flow? I suspect my issues are related to either insufficient air or varying fuel supply.
But not sure how to test for either other then go ahead and make sure there is no issue with either.... I would prefer to have the exterior air source anyway so I can close up all the air leaks elsewhere in this old house..... Please provide some guidance..... Thanks.... Great site by the way.
Best of the web. - Lee 1/20/12
Hi from Lee again, My burner is continuing to do the intermittent gasping sound. he nozzle has been cleaned and checked repeatedly and has not changed this pattern of running, then gasping, then running fine again. Now that warmer weather is approaching I would like to resolve it before the next heating season. Just not sure where to start to resolve this.. 3/21/12
Dirt in the fuel supply, dirty filter, dirty filter screen in the fuel unit, bad fuel unit, slipping coupling between the fuel unit and the electric motor that drives the oil burner, even a loose wire, are examples of causes of intermittent stopping of the oil burner. Also try cleaning or just replacing the cad cell eye. Last and most expensive is a control swap out.
Question: Nuway oil burner, won't keep running
Hi i had a Nuway burner, its ignition ignite and run for about 5 sec's and blackout again. I change the photocell, put new transformer, clean burner but still encountered same problem. - Paula Vatou 1/24/12
Paula, you don't mention an investigation of the fuel supply, that's where I'd look if you are confident that the electrics are ok. Check that there is oil in the tank, a clean oil filter installed, a new screen in the fuel pump, and air has been bled out of the oil lines. Then see if you're getting oil out of the nozzle.
Question: Grant 50/90 heating boiler ran out of oil, trouble getting started, now buzzing, won't fire
hi i have a similar issue to clark as above i have a grant 50/90 boiler which ran out of oil and was filled and bled as normal it took a while to start but was running for 20mins then cut out i went to press the red reset button and it started making a buzzing noise and now will not fire on its own i have to press the reset button 30-40 times it will fire for another 20 minutes as normal but cuts out again any ideas on whet i have to replace or check?
Question: waste oil furnace air pressure problems - what to check
I installed a small hot shot waste oil furnace from clean burn a few years ago. It is a used furnace but a brand new oil burner. Every winter when using it, I have to constantly adjust my air pressure up and down through out the day, if the flame goes out or if it gets to high and rumbles. When it rumbles it blows out threw the peep hole, which I need to keep open or the flame goes out like there is not enough air for the burn. I was thinking maybe the oil burner was set up for a bigger furnace but then reading this I realized there was never a draft control put in the stack pipe. Could this be causing my problem? Thanks for any help! - Vince 2/7/12
You could have a combustion air problem but I'd look first for a dirty oil burner nozzle, improper air shutter adjustment on the burner. or a fuel unit that doesn't shut off cleanly, accumulating sludge and crud on the nozzle and causing startup problems. Bad electrodes or a bad transformer that is failing can also give the symptoms you describe.
Question: oil furnace won't work, the furnace hums but doesn't fire
My oil furnace is not working properly. The reset button is pressed in and the furnace is humming but not firing. Sometimes when I shut off the power switch and turn it back on it fires but doesn't stay on more for more than 2 mins. The water pump is hot to the touch but the pipes are cold. I bled the water this morning it was black and there was a lot of air in it but it's still not heating up or even staying on for that matter. What could be the problem? please help. - Tony 2/9/12
Reply: let's sort out oil burner no-start problems into fuel problems vs. air problems vs. normal operation of the systems
Tony, I'm not sure what "humming" means to you but some possibilities that occur to me include
The oil burner motor runs but you don't get ignition - which can be caused by a number of problems that typically sort out to either a fuel problem (clogged nozzle, clogged oil filter, clogged fuel unit strainer, dirty nozzle, bad fuel unit, airbound fuel lines, or no oil in the tank), or an electrical problem (no power to the burner, a bad primary control, an electric motor that has failed and is stuck)
Circulator pump hot to the touch means that the heater was working previously - enough to heat water in the system. If you call for heat and the water temperature is within the specified range set by the HI limit on the aquastat, then it's normal for the circulator to run for a while - the burner won't come on until the temperature in the boiler drops about 20F below the HI.
Question: can I change the oil burner nozzle size in my oil burner?
can i put a different size nozzle in my oil burner - Ken 2/10/12
Yes, you can ask your heating service technician to change the oil burner firing rate up or down in gallons per hour (GPH) but JUST within the range of firing rates on the data tag found on your boiler or furnace.
Watch out: the oil burner nozzle firing rates in GPH listed on your heater's data tag assume a particular PSI of oil flow through the burner, typically 100 psi to 120 psi). If your service tech has changed the pressure away from factory the oil burner nozzle size may need to be set down to accommodate that amendment.
Question: oil burner flame is pulsing
The fan is running but flame in burner pulsates on and off and repeats every 5 seconds...what gives? email@example.com - 2/14/12
Sounds like a bad control switch, loose wire, dirty nozzle or similar issue.
Question: we have soot all over our house - service company didn't find any problems with the oil burner
We have soot all over our house, had our oil burner (6 years old) service and it was clean and they found no problems. There was no soot in the basement. The tech. said that soot is coming from burning candles. The soot is mainly above the heating elements. I burn two candles in living room and yet there is soot in all of the rooms. Could it be candles that would cause this much soot? - Sheldon 3/26/12
Reply: check for thermal tracking
First let's make sure that the "soot" is really soot from the heating system not from some other source, or not soot at all. Burning two candles might make soot, especially scented candles, but in my experience burning candles in one room doesn't soot up the whole house.
If the soot were coming from the heating system through ducts you'd find soot depositions in the ductwork and at supply registers.
If soot were coming from an oil burner puffback you'd find soot at the boiler room or furnace room
You should take a look
Question: New Yorker Boiler & Riello R6 Burner - can't get it working
I have a NY Boiler and a Riello R5 burner. I came home today and the boiler was cold. temperature was down to 80 on my gauge. Tried to fire up the burner nothing happened. Bled the burner so it is getting oil. Checked the Aquastat and I am getting power to the burner. Powered it all down and on again. Side vent starts, aquastat clicks but burner doesn't fire. Any ideas? - John 5/13/12
You could be out of fuel, have a clogged oil filter, have a clogged oil burner nozzle, a burned out oil burner transformer, damaged oil burner electrodes, an electric motor failure at the oil burner (check for a thermal reset switch), no power to the oil burner, or a bad primary control, or something else I haven't thought of.
A reasonable sequence of steps is given at the top of this article, including these steps
Question: moldy smell from window air conditioner
in summer we had musky moldish smell believed from window air conditioner-cleaned it WELL-still bad smell-gave it away-no smell from new owner-couple months later plugged in room portable heater BAD musky smell-can find NO mold did mold test had regular molds everyone has-WHATS CAUSIN THIS-have a carpet in this room-this room only has the smell with air cond. use or heater use? - Randy 10/6/12
Randy, most likely the mold test you performed was unreliable, even junk science given the description in your message and the continuation of the moldy odor.
Somehow you are discussing this question on a hot water heating boiler page. Anyhow, information about mold in air conditioning systems is at MOLD in AIR HANDLERS & DUCT WORK
Question: is it possible to replace the heat shield in my oil burner combustion chamber?
The heat shield in my oil boiler burner box is damaged, dan it be repaired? it is a foam type shield. - Bob 10/9/12
Reply: yes and it is a critical safety feature that needs to be fixed
Bob, I've never seen a foam heat shield and can 't imagine what that might be. But there are various types of combustion chamber liners in the fire box that contains the oil burner flame, ranging from fire-brick through pre-formed factory-built combustion chamber liners to a wet-pack kit used to repair or reline a combustion chamber through the oil burner mounting opening.
Watch out: The combustion chamber liner is critical for safe, proper oil burner operation, serving at least two functions:
Question: smoke came out of warm air heating supply vents when I turned on the heat.
I just turned on heat for first time this season . At start smoke came out of vents all over house for about a minute then stopped. It was white not black. We vented house and it did not happen again. Is this normal? - Donna 10/9/12
Watch out: Any smoke coming out of heating vents is a sign of trouble and unsafe conditions. You should not run the heating system until the system has been inspected and if necessary, repaired. While I can imagine a few scenarios that might produce a smoke-like substance at first heating startup of the season (perhaps A/C condensate leak on the heat exchanger) what you describe is certainly not normal and as it could be an unsafe condition it needs attention.
Question: loud gurgling sounds coming from oil fuel line
I have an oil storage tank in my basement. A few years ago I had new valves and orange-colored fuel lines (from tank to burner) installed. Over the past several months when the oil burner is running there is a loud gurgling/rumbling sound on the first floor of the house, but can't be heard in the basement. I thought it was the oil burner but it actually seems to be coming from one of those orange fuel lines coming out of the tank. Any suggestions? - Kevin C 10/19/12
Ask your service tech to check for leaks in the oil supply or more likely return line or it's connections.
We had a furnace installed in December. Since then we have a rumbling whenever the furnace kicks on. The rumbling vibrates the entire house. The installers have been to the house three times and cannot locate the problem. They changed the flapper and added some vent work. The last time they came they thought we needed to change our oil tank. - Nancy Plummer
Reply: rumbling oil tank or rumbling oil burner?
I'm not sure how an oil tank would cause rumbling in an oil fired heating system, except indirectly: if the oil tank were badly contaminated with rust and sludge it could cause repeated oil burner nozzle clogging and improper oil burner operation. I'd ask the oil heat technician to be more specific about why they made that recommendation. [Incidentally oil burner noise does vary with the nozzle brand, size, and pattern.]
Rumbling sounds at the oil burner itself are often a flame adjustment or a less than optimum choice of oil burner nozzle, as we discuss in the article above
Question: oil burner noise & smoke at startup or shutdown
I changed the oil burner nozzle, now it smokes when firing;
I just changed nozzle on my furnace. I "snugged it" as instructed by tech at plumbing supply house, used metal gage to properly gap electrodes, reinstalled all and it appears to be running fine, except that a small amount of smoke is coming from the barometric damper every time the unit is in firing mode. Suggestions? - Jim 1/14/12
Just finished a boiler rebuild and heating system recommissioned and working fine. When the furnace starts the start up noise is different from the previous noise. The only way I can describe it is that the noise is more of a whoomph which stutters 3-4 times. Could that be too little air supply? I have not had the flue gases checked yet, can't get a technician with a test gauge for a few weeks yet. Any ideas? - Ian 2/11/12
My oil burner, Riello f3, fairly new, produces black smoke out the chimney on startup. It was tuned up when it was installed. However, I just noticed that the Air settings and the turbulator setting is far off from that recommended in the boiler manual for that burner and nozzle. What causes the black smoke? Is it normal? - J.L. 10/1/12
I have rumble noise on oil burner shutdown, starts and runs fine - Dennis 11/28/12
Our oil furnace is smoking do I need a repair man out to the house? - Kim 11/30/12
Reply: things to check when the oil burner smokes or is noisy at startup or shutdown
The air suppy may not be adjusted properly;
Also, if you over-tightened the oil burner nozzle onto its mounting head you may have stripped threads between those parts. I did that (only once) and had a heck of a time figuring out what was wrong. When you strip threads at the nozzle (typically steel, mounting in a brass nozzle line adapter) the result is oil at 100-140 psi spraying out around the leaky mount when the oil burner is running, and smoky burner operation; if you see that problem (try starting the system briefly with ignition off so you can look for oil spray) you will have to replace the nozzle line adapter as well as nozzle.
Ian and Dennis,
A quick stop valve makes sure that the oil supply stops cleanly when it should, which often will cure the rumbling noise you describe. If you do not fix the problem the risk is an accumulation of unburned oil in the combustion chamber (left at shutdown) that is ignited at start-up, leading to our next warning:
J.L., Ian , Dennis & Kim:
Watch out: a smoky oil burner is often headed for a very messy and potentially dangerous puffback. I suggest calling our heating service company, discuss with them what you are seeing, and schedule a service call accordingly.
Question: low on oil, oil burner went off, gauge is not reliable
I just got a (3.57 a gallon!) first oil delivery of 100 gallons at the house I am renting. I only went through 3/8+/- of a tank from May til last week (I live on Cape Cod, MA--just getting into the 40s here--the oil was only used to heat hot water until a few weeks ago--now daily for heat and hot water);
I wanted to wait until the tank was at @1/8 full-bad idea. (I am a disabled single mom w a 9 year old) I thought I was ok to wait for my next SSDI check on 12/3 but "ran out" of oil on 11/24. I finally got some $ to get 100 gallons. My evil bad-tempered landlord (think the Grinch without good qualities said if the tank was "broken", I would be held financially responsible. She never said what level to fill at--I had paid her $300 at move-in for 1/2 tank)
The gauge is obviously not reliable--my landlord claims the tank was cleaned and gauge is accurate, BUT if I added 100 gallons to a 275 gallon tank, and the tank gauge is now over 1/2, math tells me that there must be over 40 gallons of sludge/unusable oil!? (I paid $300 in May for the half tank that was left by previous tenant or after landlord used 1/2 tank -- hard to get the answer from the Grinch; if the gauge said 1/8 left for the sake of this theory--and I added 100 gallons and got over 1/2 tank, and half tank is 137.5 gal, then at least 37.5 gal is not usable!) right? Also, it is making a LOUD clanking noise--did prior to delivery but not as often--what is this? Thank - Amy Lynne 11/30/12
If the oil tank is not kept sufficiently full, indeed air or sludge drawn into the oil lines can clog the filter or leave the oil burner air-bound - risking loss of heat, frozen pipes, expensive building damages - events worse than just the cost of hiring the service company to bleed air out of the system and keep the system running.
If you think that the oil heat usage rate is abnormal you can check that view by asking the oil company about the home's oil consumption in the past.
And yes, oil gauges are not precise - and can't be given the shape of the oil tank, unless special electronic and calibrated devices are installed - not a usual practice.
And yes, for oil tanks whose oil lines are taken off of the top of the tank, the bottom fraction of oil in the tank is not usable - the oil pick-up line does not extend all the way to the tank bottom as the tech wants to avoid picking up oil sludge or water - also leading to heat loss. But you're not being robbed - if the oil couldn't be take out of the tank before your tenancy it was there at the start of our lease. You were not robbed. Search InspectApedia for OIL TANK GAUGES to read details.
Loud clanking noise or any other odd noise from the oil burner merit prompt attention from the service company as you risk not only loss of heat but a puffback or other unsafe conditions.
You should check your lease terms with an attorney but most often the tenant is indeed responsible for keeping oil in the tank and heat working lest the home be damaged. Don't cut it too close to the wire in ordering an oil tank fill-up.
Question: oil burner fumes & odors after burner shutdown on power-vented heating system
I have a power vent on my oil, hot air furnace. The furnace seems to run fine but I'm getting residual smell/fumes in the basement after the temp is satisfied and furnace shuts down. Is this normal and if i replace the vent will it fix the problem? The equipment is 12 years old. - Jake 1/11/2013
Jake, I'd take a look at the operation of the power venter during the shut-down cycle and compare that run time with the manufacturer's specifications. It may be that the system needs a purge cycle. Also look for heating oil drips or leaks around the system.
Question: how can I quiet down my noisy oil burner assembly?
I have a WeilMcClain Oil burning with current specs: 77.5% efficience 8% CO2 Cleaned and tuned every season I can only guess the burner is approximately 20 years old +- My concern is the increased roaring sound during burn ( The burner is used for heating only). In past years I've heard the burner run quite a bit quieter and, in fact, my tech whom I've had visit twice says everything is fine.
The smell of oil is noticeable whenever I turn up the thermostat. I am sure both the roar from the burner along with the specs can be improved ( you've heard that before from a layman). What questions would you recommend I ask the tech and/or is it time to look for a new burner and serviceman? Safety concerns are firsthand every time I fire up the burner. Thanks-M., Gloucester MA. 1/13/2013
Ask the heating service tech to give an opinion about the cause and meaning of the noise you hear. Some noises may be due to improper and even unsafe burner operation such as a dirty system, dirty heating system, misadjusted oil burner, simply the choice of nozzle type, loose parts that are likely to lead to a heating system failure, some other operating defect we've not listed, or in most extreme case, chimney fire (an immediate hazard in which case you should leave the building, turning off heat if you can safely do so, and call the fire department) .
The fact that you smell heating oil suggests that the heating system is not working properly; there are several ......
Even in the case of an oil burner that is properly cleaned, tuned, and adjusted, choice of settings (for example oil line pressure) and oil burner nozzle type can cause changes in the sound of the burner. Also as a rule, newer high-speed (3450 rpm) oil burners are more noisy (and more efficient) than older low-speed (1725 rpm) oil burner assemblies. In some cases the service technician might try a different oil burner nozzle (such as the Monarch AR for "anti rumble") to see if that helps with noise reduction.
In sum I agree with your priorities:
For a system that is operating safely and properly but for which noise remains a problem I'd look at
Question: exhaust smell coming from the furnace.
I have an exhaust smell coming from the furnace. Repair people have been out twice and have no idea where it is coming from. Furnace has been cleaned a new transformer and nozel have been placed along with all systems checked and have been told there is nothing wrong !
This matter is potentially dangerous and not one that can be reliably diagnosed from just the information in your note.
Some things to consider:
- Make sure that you have correctly identified the type of smell and that you've had it corroborated by a second person who can help locate where it is strongest and what is its nature.
- If the smell is related to the heating system then most likely the equipment is not operating properly and may be unsafe or at least unreliable - risking loss of heat or dangerous flue gases escaping into the building
- If there is a relationship between the smell and your fireplace but the smell is of heating oil then there may be an unsafe and hidden leak within the chimney: heating appliances cannot share chimneys with the fireplace and certainly can also not share venting of appliances or fireplaces on different floors.
You need a professional heating service call - discuss your concerns with the heating company manager;
You may also need a professional inspection by a certified chimney sweep.
Question: roaring Buderus heating unit with Riello burner
(Mar 16, 2014) Michael said:
We just replaced a crumbling System 2000 hot water heating system with a new Buderus unit with a gross output of 136 MBtu/h and a net output of 119 MBtu/h.
First we had to line our chimney with a steel exhaust pipe 5" - 26 ga to meet code. No problem.
A few days later the new Buderus unit was installed with a Riallo burner ( sp?).
It ROARS! You can hear it throughout the house. Heck, you can even hear roar it out on the street!
The installer replaced the first burner with a supposedly quieter Becket AFG with a 0.8560B nozzle.
No change and the installer gave up. You can still hear it out on the street.
Anybody have any ideas on this one ??
Tell us the model of your Buderus heating boiler;
Also, is the chimney and vent system using a power vent or just natural draft?
And can you trace the noise more precisely to the burner, vs. boiler vs. chimney?
Finally, if the old unit was a slow speed 1725 rpm oil burner and the new unit a hig speed 3450 rpm burner motor, it's normal that newer high speed oil burners are noisier than the older units - which can be a shock to some homeowners.
If we decide that the unit is working normally and safely we'll discuss other noise control measures.
Question: Camray boiler making banging noises
(Mar 24, 2014) Anonymous said:
my oil fired Camray boiler keeps making banging noises. what is the cause of this. This boiler is an outside wall mounted boiler
Watch out: "Banging" noises inside an oil burner / boiler might be a sign of improper burner operation and risk a dangerous Puffback.
Question: strong oil odor smell in house
(Apr 26, 2014) Orlando said:
As soon I enter my house I have this strong oil odor smell. I went down to the basement and I don't see any oil coming out of the line, filter or even the furnace itself. The filter was changed 2 month ago, a valve was changed and everything seems to be working in good condition. I have heat to the house and water. what it could be?
Orlando if you are sure it's a heating oil smell you'd want to check for
- a recent oil delivery that spilled outside
Question: carbon formed when buring diesel in commercial bakery oven
8/29/14 steevan said:
hi, we are using diesel burner for bakery production. Inside oven, more carbon is formated even diesel pressure is perfect. What would be the reason?
Sounds like a burner or venting design problem and possibly an unsafe oven. I'd ask for help starting by contacting the oven manufacturer.
(Aug 30, 2014) steevan said:
hi, we are using diesel burner for bakery production. Inside oven, more carbon is formated even diesel pressure is perfect. What would be the reason?
Sounds like a burner or venting design problem and possibly an unsafe oven. I'd ask for help starting by contacting the oven manufacturer. Keep us posted.
(Sept 5, 2014) Mike Xiao said:
Hi, everything was fine wnen we shut down the oil boiler three weeks ago before our vacation. But we found a lot of smoke/odor last night within 5-10 minutes after we returned home and re-started the system. What is the potential reason and what to do next? Thanks!
Mike your oil burner needs to be serviced by a professional. Could be just a cleaning and nozzle, filter & screen replacement or could be something else like a oil line or valve leak.also check the condition of the chimney and flue.
More possible causes of oil burner smoke and noise are in the article above.
(Sept 30, 2014) richie said:
firebird oil boiler very hot hours after central heating being switched off is this normal
Possibly - check that the burner is really OFF.
Question: strong oil smell
(Oct 8, 2014) Anonymous said:
Strong door smell of oil in house
If the odor is of home heating oil I'd check through the article above, starting at the oil burner and boiler or furnace or oil fired water heatr and at the oil storage tank. If the system is producing smoke and operating oddly shut if off for safety.
(Oct 10, 2014) paul said:
Oil ran out after sometime I got oil boiler wouldent fire up motor was tight took pump off motor OK pump had like water in the car like rust I cleaned it out put it back together its still tight should I get a new pump
I think the pump is probably damaged from corrosion.
10/31/14 PC said:
I can hear water flowing (loud gurgling) into the back of our outside oil boiler. The noise can then also be heard in the pipes inside the house. Lasts about 20 to 30 mins. Is it likely to be the water pressure coming into the house ( too low or to high)?
more likely there is excess air in the system
Question: loud gurgling in the back of our heating boiler and in heating pipes
(Oct 30, 2014) Martin said:
More likely there is air in the hot water heating system - which in turn may mean that an automatic air purge valve is not working. The risk, beyond the noise, is ultimately loss of heat if the hot water piping becomes air-bound. Find and fix any automatic air purgers and ask your heating service tech about purging the existing air.
(Nov 9, 2014) Anonymous said:
The system needs service. We don't know if you're finding a problem with fuel delivery, clogging, a loose wire, bad draft, or just a dirty nozzle
Question: oil burner smells
(Nov 15, 2014) Anonymous said:
Question: neighbour complains of dense black billowing smoke from my oil burner's chimney
(Nov 22, 2014) Peg said:
(Dec 12, 2014) Jarrett said:
Watch out: Your heating system is not operating properly - could be a dirty nozzle, bad oil burner blower fan, or lack of combustion air or something else. I would SHUT DOWN the system and call for emergency heat repair - you risk a dangerous oil burner PUFFBACK explosion.
I would SHUT DOWN the system promptly - worryied about puffbacks and still worse mess.
If there was un-burned oil in the combustion chamber it would normally burn off in the first 5 minutes of ignition.
But you may have stripped or damaged threads on the nozzle adapter - that can cause improper spray of oil into the combustion chamber, ignition and combustion problems.
Let me know what you find.
(Jan 4, 2015) Kate said:
Kate your boiler may be coming on to keep heat in the unit to serve a tankless coil used to supply domestic hot water. If your boiler uses a convenational aquastat as its primary controller this can be the case EVEN IF there is actually no tankless coil installed.
See details at
Question: random loud oilb burner noise
(Jan 7, 2015) Ellen Bowser said:
Randomly, several times a day a very loud noise followed by the pipes vibrating when furnace starts up. Shakes the whole house. Drained the line,s change the flow and replaced flaps to allow a slower flow of water. This is so loud it wakes everyone up with a startle.
We need to inspect the equipment closely before and at the start of this noise complaint, using if necessary a mechanic's stethoscope if the sound source is not obvious. Noisy burners or chimneys can be quite dangerous; or the noise could be a circulator or even loose piping.
8 January 2015 Bob Welc said:
I call that condition "sloppy oil burner shut-down" - often caused by an air leak into the oil piping. When the burner stops running air in the piping that was at high pressure expands to push more oil out of the nozzle where it sputters for a bit. There can be other causes of this problem of course, even just a need for cleaning and service. The danger is a destructive PUFF BACK explosion. I'd ask for prompt heating service. Keep us posted.
14 January 2014 Bob Welc said:
First of all, I'd like to correct something I mentioned previously. The original company that came out to look at my heater was SERVICE MARK...NOT Horizon.
For $225.00, that guy changed the nozzle and left with the problem still occurring. I called another company, American Heating, and they spent about 2 1/2 hours cleaning things out and replaced the nozzle that was just replaced because he said it was not the correct one.
For under $200.00, the heater in now working very well with no after burn rumblings. Although they did recommend an oil burner control board for about $400.00 which is way too high. And since the heater is now working very well, I'm wondering why they would suggest that.
So I still don't know for sure what was causing the original problem. It could be the control circuit, but it could just as easily be the thermostat. The heater will be 13 years old this Feb., so I'll try to baby it for a few more years before I replace the whole thing.
Thanks for your help.
Thanks for the follow-up Bob - that will help others.
It is quite possible that the original problem was simply a need for service - a dirty oil burner nozzle assembly alone can mean unreliable operation.
Question: oil burner smoke comes out of fireplace
14 January 2015 Anonymous said:
That sounds dangerous: there may be a smoldering chimney fire or the chimney flues may be damaged so that oil burner exhaust is entering the fireplace flue.
Ask for a flue inspection by a certified chimney sweep.
keep us posted
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