Diagnostic questions & answers for a heating or water heater oil burner won't start or won't keep running:

This article reports common questions & answers for people who are having trouble getting an oil burner to start & run properly.

This article series answers most questions about all types of heating system troubleshooting, inspection, diagnosis, and repairs. We describe how to inspect, troubleshoot and repair heating and air conditioning systems to inform home owners, buyers, and home inspectors and students of heating service methods about common heating system defects. The articles at this website describe how to recognize common oil-fired heating appliance operating or safety defects, and how to save money on home heating costs

Oil Burner Won't Start or Run Properly: Diagnostic Questions & Answers

See OIL BURNER WONT RUN for a flowchart of diagnostic steps for an oil burner that won't start or won't keep running: what to check in what order . This article series explains the inspection, diagnosis, & repair of oil burners used in heating appliances such as hot water boilers, steam boilers, & water heaters. Page top oil burner skech was provided courtesy of Toronto home inspection & education company Carson Dunlop Associates, a Toronto home inspection, education & report writing tool company [ carsondunlop.com ].

On 2017-11-20 by (mod) -

Usually when a burner is having a short and odd on-cycle the problem is traced to a loose electrical connection, a defective control, or poor thermal contact between the primary control's temperature sensor and the wall of the metal well into which its inserted. Some techs omit the thermal-conductive grease, making that problem worse.

If the problem were sludge in the lines you'd be able to see that showing up at the burner as loss of fuel supply and as crud in the oil filter, oil pump strainer, and at the nozzle itself. Ask to see that evidence.

Finally, if the problem is traced to a need to replace the oil lines, the new lines do not have to be run under the slab.

On 2017-11-20 by Eric

My 27 year old Blue Angel Wayne oil burner(on an Utica boiler) started firing up for 10-15 seconds, then shut off for 45 seconds , then fired up again and ran normally until it would cycle off again normally and then the whole on-off-on cycle would start again.The unit is serviced regularly by an oil service company, all filters have been replaced,transformer on top of burner replaced, the pump has been replaced with a larger one to accommodate the 35 foot lines from tank to burner and tank was checked for sludge which was minimal.

The pump replacement has decreased the burner "off" time from 45 seconds to 6 seconds, but no one can figure out why the burner is turning off and then back on. The oil company keeps saying it's sludge in lines and would like to put in another tank closer to the burner ($$$$$!). If it was sludge, wouldn't the filters be clogged (which they never are) and why would the burner turn on again and run fine? The oil lines are literally under the concrete slab of the house so I can not just replace the lines and I can't convince anyone to blow them out! Any help with this would be greatly appreciated!

On 2017-05-28 by Bill

CAD cell or something go wrong with the boiler oil and not shut down and and cause chamber to flood

On 2015-03-29 by (mod) -

Tony you need to shut the system off now. What you describe sounds like an oil leak, maybe at the nozzle adapter. The risk includes a puffback explosion.

On 2015-03-29 by Tony

I have a Weil-Mclain's furnace with a Beckett gun on it. I changed the tip and filter on it. There is a strong oil smell coming from the furnace it. When it is done from a firing cycle there is a small flame around the nozzle. Plus there is excess oil coming out the bottom of the chamber door. I have been doing the service work on my furnace for years an never had this problem before. Any help would be appreciated

On 2018-11-18 by (mod) -

Donald

An oil burner oil delay solenoid uses 120VAC

On 2018-11-17 by Donald

What does the solenoid valve use for voltage? On a normal oil burner

Question: oil burner rumbling noise & smoke at startup or shutdown

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

Reply: things to check when the oil burner smokes or is noisy at startup or shutdown

Jim: see OIL BURNER RUMBLING NOISE

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.

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

Reply:

Tom,

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: 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

Reply:

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: 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

Reply:

Vince,

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.

See OIL BURNER RUMBLING NOISE

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.

See OIL BURNER HUMMING NOISE

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? earlgallant@eastlink.ca - 2/14/12

Reply:

Sounds like a bad control switch, loose wire, dirty nozzle or similar issue.

Question: oil burner won't run, it buzzes

(Feb 5, 2013) Brian said:

My oil furnace cuts off several times a day. As it goes to cut back on, the thermostat will click, and there is a buzzing sound at the furnace. After a few seconds of buzzing, the red button will trip. After I push the red button to reset, it will buzz again, but a light to moderate bump to the top of the igniter will cause the furnace to kick on. I've already replaced the igniter. Any idea what could be the issue? Thanks

Reply:

When the oil burner trips off on safety reset DO NOT keep pushing the reset button. Once is OK. More than once floods the combustion chamber and makes actual service and repair more costly, difficult, and dangerous. Your heating system needs service and repair by a traine service technician. Some typical reasons for oil burner failure are in the article above.

Question: oil burner won't run after sitting for two years

(Oct 11, 2012) Jeff said:

I've been trying to help a friend resolve a beckett oil burner problem. He says it ran fine for years then sat unused for 2 years. When he tried it the first time it fired up and ran fine. But since then it won't ignite. Any insight into what could have went wrong? I tested everything electrical and all seems fine.

I smell fuel after it tries to start (when I open the view door)

Perhaps the flue had a nest in it or something which wasn't obstructing, but after it ran it pulled it down and clogged the air flow? Maybe I can bypass the flue to see if it that resolves it? Could the fuel have gone bad but ran once for a few minutes and now just won't ignite? Any insight would be well appreciated.

Reply:

(Oct 15, 2012) TONI said:

I can say is that the system is clogged and due to waxing.Its never good to have it running then to just stop running for two years!I would say it could be the pump,nozzel,I would check everything in the whole system.Thee circuit board,the thermostat,the low water cutoff switch,the blower motor.You need to hire HVAC/R tecnic they are the only ones can better dignosis the problem and fix it!

D Friedman added

Toni,

I agree in part with your diagnosis of Jeff's problem getting an oil-fired heating system working after a prolonged shutdown, but the terms need to be clarified.

WAXING refers to gelling of heating oil - something that occurs at very low temperatures. This is not likely to be Jeff's problem.

But solidified soot and creosote and similar deposits inside the oil burner assembly as well as in the heat exchanger often form when a system is left shut down for a long time, especially so if the system was not thoroughly cleaned promptly at the time it was taken out of service. This is a reason that we recommend that annual oil-fired heating equipment service and cleaing is best performed at the end of the heating season rather than at the start of the next one.

Question: repaced nozzle, oil burner won't run

(Nov 9, 2012) jessie said:

i replace my nozzel 075 on my beckett burner now it will not contunie to run, i thank its my cad cell and oil primary control, what
do you thank what it is,thanks

Reply:

Jessie, if the system was running before you replaced the nozzle and it won't continue to run now, start by reviewing everything you touched to see what was left askew, disconnected, dirty, or improperly adjusted. Try the flowchart above on this page.

Question: oil burner works intermittently, goes off on reset

(Jan 22, 2013) AL-Amin said:

Our Burner is recently serviced by a expert who claimed has changed: nozzle,cad cell, fuel pump and oil filter, and all other things, after a month it is now working intermittently, once reset, it goes until the thermostat switch it off and never come back unless I press to reset it(However it will only start when the heat exchange pipes are not warm).

Now the expert is quoting 5000 dollar to replace my over 20years old peerless (2.5gph, 760sqf steam), and only 8 years old Beckett burner. The chimney were also cleaned a year ago. Please advice!!

Reply:

If your oil burner does not run after having it serviced, call the company's service manager and politely ask for a more experienced service technician.

Do NOT keep pushing the reset button - that can be unsafe.

Questions about oil burner heating service techs and DIY oil burner servicing:

(Jan 27, 2013) Bob said:

Quite a few years ago I used to get qualified service men to do the yearly service on our oil furnace.,
I always ended calling therm back the next day because they always screwed something up. Being a home maintainance person, I look up in my old Popular Mechanics Encyclopedia set from the 1960's. And it is there where I found out how to maintain and do all the service on my oil furnace.

There are five pages on how to service your oil fired furnace.

For the last 15 years at least I have had no problems with my oil furnace by doing my own service work on it. I could never find anything on the internet on how to set up the electrodes for proper ignition etc. over the nozzle, but it tells you there in the Popular Mechanics Encyclopedia.

I also have not replaced the nozzle over the years (I do clean it yearly)and the furnace works fine for a Fifty year old machine.

Reply:

Bob, while we support basic tasks that a homeowner can do, even inspecting for obvious signs of oil burner malfunction such as soot, odors, leaks, noises, without actual training and proper equipment one cannot properly adjust a heating oil burner.

Older oil burners were more tolerant of modest mis-adjustments and would limp along throughout the season. With the shift to modern high-speed 3450 rpm oil burners and higher efficiency heating boilers and furnaces, more accurate adjustment of oil line pressure, combustion air, draft, and more thorough attention to filters, nozzles, electrode adjustments, oil pump fuel strainer, are necessary for proper, safe operation.

In several decades of working around oil fired heating equipment, while I sometimes found an oil burner that had been chugging along unattended for several years, I generally found that oil fired heating equipment really needs an annual cleaning and service to run properly, safely, and reliably.

In short, lucky to have a 50 year old machine that is still fairly simple to tune and adjust, but even then I would not assume you're running the system at its optimum adjustments - which means you risk wasting money on fuel. If it were my system I'd think it's long past time to ask for an inspection, cleaning, and tune-up by a trained heating service tecnician.

Question: crud on the end of the oil burner tube

(Dec 23, 2012) Anonymous said:

I have a oil build up on the end f the blast tube that sealed the end up

Reply:

Anon, you describe a symptom of a system that needs cleaning and service. The turbulator or blades on the end of the oil burner tube are there to give a desired pattern and movement to combustion air as it enters the combustion chamber. A dirty nozzle or burner operation clogs the turbulator, eventually to the point that the burner will fail to ignite and run properly. A heating service tech who fails to inspect and if needed clean the turbulator is not doing his or her job.

Question: how to re start boiler after oil ran out

(Nov 10, 2015) Anonymous said:
need help restarting oil water heater after oil ran out

Reply:

Doubtless you have air in the oil lines, oil filter, and oil burner; those need to be bled - a task for a service technician.

Search InspectApedia for BLEED AIR FROM OIL LINES or see OIL BURNER FUEL UNIT diagnosis and repair guide

...

Continue reading at OIL BURNER WONT RUN - Diagnostic Steps - what to check in what order, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

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OIL BURNER DIAGNOSTIC FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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INDEX to RELATED ARTICLES: ARTICLE INDEX to HEATING OIL, OIL BURNERS, OIL FIRED HEATERS, OIL TANKS

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