Oil burner rumbling noise or sound troubleshooting:
Some oil burner noises are normal, others including loud rumbling indicate trouble and may even be dangerous. The rumbling oil burner noise discussed here may also be described by some people as oil burner pulsing or oil burner pulsating.
This article series explains how to recognize & diagnose the cause of oil fired heating boiler noises, leaks, odors, or soot and smoke.
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These causes of oil burner rumbling or pulsating noise are given roughly in order of probability.
2019/11/16 Chuck said:
I installed a new Weil-McClain WGO4 oil burner to replace the 21 year old same model.
This unit makes loud thunder noise while running.(flame noise ?)
Is this normal for a newer model?
The sketch above is provided courtesy of Carson Dunlop Associates, a Toronto home inspection, education & report writing tool company [ carsondunlop.com ]. [Click to enlarge any image]
Some noise is normal however, but the normal sounds tend to be more smooth and continuous.
But an increased rumbling noise can be a sign of burner, combustion chamber, or even chimney problems.
Newer oil burners will be somewhat louder than much older models for both good reasons to tolerate and bad ones to correct.
But if the rumbling is due to poor oil burner operation or the choice of the wrong burner model or tube length or burner nozzle those errors can make the system unsafe.
Start by confirming that the oil burner model including tube length, spray pattern, turbulator design are proper for your boiler or furnace combustion chamber.
Continue by making sure that the system is properly adjusted and tuned. Measure the system standard heating tuneup parameters including smoke and CO2 to verify that your adjustments have improved, not hurt, system performance.
Some steady rumbling noise at a properly cleaned and adjusted oil burner is normal, but there are things a technician or homeowner can do to reduce the creation of those sounds or to reduce their transmission to the building interior, such as sound-insulating the boiler or furnace room walls or ceiling (with appropriate fire-resistant materials).
We have also had good success at reducing rumbling noises at older oil burners by changing to a Monarch AR oil burner nozzle of the proper size or an equivalent "anti-rumble" burner nozzle from other manufacturers. Often we also found better combustion efficiency using hollow-cone oil burner nozzles that can be more quiet.
See OIL BURNER ELECTRODES for details.
Some oil burner motor noise that's normal is also called "rumbling" or "roaring" by some of our readers Newer oil burners use a motor that spins at 3450 RPM ("high speed burners") that permits more-efficient oil burner operation while older burners used a motor that ran at 1725 RPM ("slow speed burners"). The newer motors are often a bit louder and whinier than the old ones.
But that noise difference is generally tolerable. Some readers described the motor noise as rumbling though in my opinion it's not.
Any oil burner, if not properly adjusted or selected for the combustion chamber into which it's being fired will not work properly and may produce loud flame / burner noises, particularly a rumbling sound.
Watch out: loud rumbling noise at the oil burner could be a sign that the burner (or if you're lucky just the nozzle) is the wrong model:
d if the flame is too long, for example due to a too-long oil burner tube that projects too far into the chamber, or a nozzle that produces a flame that is too long rather than shorter and wider, that can cause incomplete combustion, poor operation, rumbling, sooting, and even risks a
dangerous OIL BURNER PUFFBACK EXPLOSION
So first off ask your heating oil technician - who knows more than you or I do - to check the oil burner model and oil burner tube length, nozzle spray pattern, nozzle gph rate, and oil burner tube turbulator end all against the boiler or furnace combustion chamber design and specifications in the boiler/furnace IO (Installation and Operation) manual and on the oil burner itself and its specifications.
IF all of those specifications match (I suspect they don't) then you might ask about an AR nozzle as I'll explain:
Now oil burner rumbling noise isn't new and in fact some oil burner nozzle manufacturers include an "AR" nozzle model or "Anti-Rumble" nozzle. Sometimes I used to stick on an AR nozzle and my clients would notice that the flame and burner were noticeably more quiet. So you should ask your oil burner technician about this options.
Some heating system and heating oil burner noises are considered normal.
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.
The cause, diagnosis, & cure of rumbling sounds at the oil fired heater are discussed in detail
Rumbling at the oil burner may be normal but often indicates improper adjustment, need for cleaning or service as we discuss in the article OIL BURNER NOISE SMOKE ODORS - home
Watch out: some of these conditions can lead to a dangerous OIL BURNER PUFFBACK EXPLOSION
Chimney fires: Watch Out: DANGEROUS, IMMEDIATE ACTION NEEDED: Very loud noise like a roaring freight train coming from a chimney is likely to be a chimney fire- extremely dangerous, risking a house fire: turn off heat as you run out of the house: call the fire department from your cell phone or from a neighbor's house.
See CHIMNEY INSPECTION DIAGNOSIS REPAIR for details of chimney inspection, diagnosis, and repair
First let's name the "normal" noises at an oil burner.
Oil burner noise is that is normal tends to be more smooth and continuous, without rattles, bangs, significant vibration or rumbling or stumbling.
Of these noise components, the oil burner flame or combustion noise is usually the loudest "normal" noise coming from an oil burner.
The electric motor powering the oil burner's blower and fuel unit also may generate some electric motor noise and there may be a bit of vibration that can be transmitted into the building through piping or other heating system components.
The fuel unit pumps
heating oil to 100 psi or higher, then sprays it through an oil burner nozzle where the oil is ignited by electrodes mounted
in the oil burner's tube at the entry to the combustion chamber.
The "roar" that you hear at a normally operating heating system oil burner is usually produced mostly by this combustion process.
Our complete catalog of oil burner noises is at OIL BURNER NOISE / ODOR DIAGNOSTIC INDEX
Here we focus on oil burner rumbling, stumbling, pulsing noises.
Has the oil burner been changed for a new, higher-speed model?
Motor speed affects oil burner noise level. Burner operating noise will be louder at new high-speed oil burners whose motor runs at twice the RPM (3450) as older burners; doubling the burner speed along with concomitant higher oil and combustion chamber pressures increase noise levels.
Careful selection of oil burner nozzle, flame retention head and head settings may reduce this noise a bit.
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Below you will find questions and answers previously posted on this page at its page bottom reader comment box.
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
(Nov 18, 2017) Anonymous said:
We moved up north last year, and not used to oil burners so forgive my ignorance. It is an old unit, and we had a full servicing/cleaning 2 weeks ago. (He said everything was working although it's old)
It's starting to get cold and we just started to turn it on. Now I am noticing whenever the heat kicks on, sometimes there will be a periodic dull/low rumbling we can hear from upstairs. (Not sure if it's related, but the flap of the draft regulator (on the stack) will blow in every time it rumbles).
Last winter we didn't have this problem. Does anyone know what it might be (if it's dangerous) from this limited information? If it's just a noisy heater I can live with that.
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.]
It is fair to say that some causes of bad oil burner operation can be difficult to track down and can be subtle.
A temperature sensor used by the aquastat and improperly installed can, for example, lead to short on cycling and sooty operation that leads to rumbling and bad flame, or a defective or clogged chimney can also cause improper operation - the list is pretty long.
From your note I can't tell if the sound source is improper burner operation, improper blower operation on a furnace air handler, or a duct work problem.
It might help to give a call to your oil heat service company and speak with the service manager. Ask him or her to send an experienced senior technician to review the problem so that your system is not only quiet, but reliable and safe.
Rumbling sounds at the oil burner itself are often a flame adjustment or a less than optimum choice of oil burner nozzle, as we also discuss in the
article OIL BURNER NOISE SMOKE ODORS
Anon,
Some rumbling noises on oil heating systems are normal. That is the oil burner is by no means a silent machine.
However loud noises, or changes in the sound from the way the system was running after your service person had cleaned and adjusted it could be signs of trouble.
And a noise like a freight train or very loud could be a sign of a dangerous chimney fire.
If I were worried about that I would dash outside and look to see if black smoke was coming out of the chimney.
If that were the case I would get people out of the house and call the fire department. So short of a chimney fire or a significant change in the system performance, or black soot or smoke blowing into the occupied space, you're probably not facing an emergency.
I would still ask the service person to check out the oil burner operation, particularly if the noise has changed. Sometimes the tech will simply need to change to an AR nozzle - an anti-rumble oil burner nozzle that can reduce the burner rumbling sound level.
Backfire every time oil furnace shuts off after heating . Not running the furnace fan on continuous just on auto . No odour no spit etc but the backfire after furnace shuts off is that dangerous ?
Yes.
With just a smidgen of information I can only guess that your oil burner is not shutting down correctly and is dribbling some in completely burned fuel into the combustion chamber the end of a heating cycle. That's risking a dangerous puffback explosion.
There could be several causes such as a leak in the oil lines, air in the system, or a fuel shut off valve that doesn't close properly in the oil pump.
You need help from a oil heat service technician.
Watch out: See OIL BURNER SOOT & PUFFBACKS
On 2016-09-03 by (mod) - a mechanics' stethoscope can help
Sometimes a mechanics' stereoscope can help find the noise source: motor vibrations can be transmitted via piping, for example. ALso check for a combustion problem or a chimney hazard. Sounds like a safety concern that merits a service call.
On 2016-09-03 by Jeff
Tankless oil burner used to heat the house and provide hot water. It is summer, so no heating.
When we call for hot water, the burner sounds normal when right at the burner, but there is a loud, continuous rumbling noise that you can really only hear upstairs in one of the bedrooms.
Getting complaints from the occupant! My daughter. Been doing this for years. I keep looking around but coming up empty. Any ideas?
On 2016-03-14 by (mod) re: noisy oil burner startup - rumbling burner
Todd
You may have a combustion air problem, the wrong nozzle pattern or size, or another mis-adjustmen
t. Unfortunately it's no longer possible to properly set up an oil burner by eye and spit - a bit of training and use of CO2, stack temperature, and smoke measurements are also needed.
On 2016-03-13 by todd
burner rumbles on initial firing then quiets down. i have a new nozzle and filed electrodes to a sharp point and adjusted .On 2015-03-20 by Rumbling noise
Same spec nozzle - sure.
AR - don't know, probably not, he just keep replacing nozzles like a gloves.
Tracking - combustion chamber, some kind of misfiring.
Stethoscope will render you effectively deaf, half of the house vibrating and can be heard all the way from across the street.
And it is sporadic, thus cycling power does not really lead to constant replication of malfunction, usually turning power off and then back on solves the problem. I'm not taking chances and trying to shut it off as soon as possible.
On 2015-03-19 by (mod) -
Rumble
Was the nozzle replaced with the same spec as original? Did the service tech try an AR (anti rumble) nozzle?
Has the noise been tracked down at all?
Try a mechanic's stethoscope on the external parts when the burner is starting up: motor, blower, fuel unit, side of boiler, flue.
On 2015-03-19 by Rumbling noise
Well, going back to rumbling noise. Nozzle was replaced so far three times, filter cleaned, etc.
Still sporadically upon start up burner trying to take off like a helicopter, in fact it does sounds like a helicopter in the basement, after few seconds of operation it does quiet itself and going to normal sounds of burning flames, or if I'm fast enough - cycling power will restart burner properly.
Yesterday, it began "warming up" engines ;-) before tech even left driveway. I'm not going to pay third time for service call, since apparently he is unable to resolve the issue.
High speed oil burners noises: older traditional oil burners used on heating boilers and furnaces were driven by an electric
motor spinning at 1725 rpm.
Modern "high speed" heating system oil burners usually run at 3450 rpm. The higher speed permits
more air flow and greater oil burner efficiency.
But in buildings where an older low-speed oil burner is swapped out for a
new "high speed" oil burner unit, the occupants are often surprised to hear that the new equipment is noticeably noisier than
the old unit.
This is normal, and your heating installer would have been smart to tell you to expect this change so you don't
think something's wrong with the new heating system. You're tolerating more noise for lower heating system operating costs.
George Lanthier (Fuel Oil News) reported on customer complaints about the increase in noise when new, more energy efficient but noisier oil burners are installed.
In a 2006 article in that publication he offered several suggestions of which his first is that oil companies should "scare the dickens out of the customer" meaning that the vendor should prepare the client for an increase in heating system noise level.
I changed the oil burner nozzle, now it smokes when firing;
Our oil fired furnace is smoking - do I need a repair?
Oil burner making a rumbling noise at shutdown;
Riello F3 oil burner is producing black smoke out of the chimney at startup
Whoomph sound at oil burner startup
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
Jim:
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,
Try installing a quick stop valve at the oil burner. Search inspectApedia for OIL LINE QUICK STOP VALVE to read details.
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.
On 2012-02-07 by (mod) -
Jane, it sounds as if you are describing a water heater (used to make domestic hot water for washing and bathing) - if the noise is coming from the tank it may have a problem with internal scale formation. Search InspectApedia for water heater tank scale
If the noise is coming from the oil or gas burner the system may be operating improperly, even unsafely, and you need a service call.
In the article links at RECOMMENDED ARTICLES see
NOISE CONTROL for HEATING SYSTEMS
or if it's a water heater you're asking about see
NOISES COMING FROM WATER HEATEr
On 2012-02-06 by jane
why is my tank in my loft making a rumbling noise, we have our heating and water timer to come on in the morning and we can hear this noise from the loft
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