Fixing an Oil Burner that Won't Run

Oil burner won't start
Oil burner won't keep running
Oil burner cycles on and off rapidly or too often
Oil burner runs when no call for heat
Oil burner fails after service call

Oil Burner Won't Start FAQs

Tip: see the oil burner diagnostic flowchart at OIL BURNER WONT RUN

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

Reply:

John,

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

• Assure that there is electrical power to the burner and controls
• Assure that the TT is calling for heat
• Assure that there is fuel
• Check various reset buttons & switches

My 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.

How to fix an oil burner that won't run after sitting for two years

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. (Oct 11, 2012) Jeff

Reply: by Toni

Jeff: 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, nozzle.

I would check everything in the whole system.

The 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! (Oct 15, 2012) TONI

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.

I repaced the nozzle, but the Beckett oil burner won't run

I replaced my nozzle 075 on my Beckett burner now it will not contunie to run, I think its my cad cell and oil primary control, what
do you think what it is,t hanks (Nov 9, 2012) jessie

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 step by step oil burner diagnostic flowchart

at OIL BURNER WONT RUN

Crown direct vent oil heater with Carlin EZ1 Burner won't restart

I have an oil fired crown direct vent with a Carlin ez-1 burner. The unit is 17 years old. In the last week the boiler shut off and would not restart on its own. The 1st time the circulator was running , the boiler was off and there were no lights on the control unit.

I flipped the emergency-off switch ( just guessing) and the boiler started back up. 4 days later the same thing occurred except this time when I flipped the switch to on, the red light on the control unit was on. I pressed it once and boiler fired up.

I did change the filter and nozzle 2 weeks earlier for maintenance. I’m stumped as to what to check that causes the shut-off condition On 2022-01-27 by Wendell

by Inspectapedia Com Moderator - don't keep pressing that reset button or you risk a puffback explosion

@Wendell,

It sounds as if your burner is not operating properly, possibly needing cleaning or adjustment.

Unfortunately, while it's mechanically easy to change an oil filter and nozzle, with modern high speed oil burners (3450 rpm motors) it is not possible to adjust the system properly without both training and proper equipment to measure smoke, CO2 or O, stack temperature, and draft.

Also, having done so myself, I warn that it's easy to make a small mistake changing a nozzle that leaves an air leak in the piping (and oil leak when the fuel unit is running), or a damaged thread that causes an oil leak, or a bumped or bent electrode that changes the gap or position of the electrode tips.

ANY of such hard-to-spot snafus can result in an improper flame, sooting, and sending the burner off on safety-reset.

Watch out: if you can re-start the burner and it keeps running for a complete heating cycle, then you may limp along while you wait for a service call. But don't keep pressing that reset button or you risk a puffback explosion.

see

OIL BURNER SOOT & PUFFBACKS

by Anonymous - I do my own maintenance on my oil burner

@Inspectapedia Com Moderator,

I understand your concerns. I’m very familiar with this system as I am the installer and have maintained it all these years.

The boiler is shutting down correctly. It just refused to start a few times. And there is no leak ( I’ve been there before also. Wasn’t pretty).

I had the co2 measured and it’s in the correct range. I’m thinking the primary control must be malfunctioning. I just need to know which contacts to check when the problem occurs again.

by Inspectapedia Com Moderator - primary control may be malfunctioning

@Anonymous,

With the apology that it's not possible to be confident in an oil burner diagnosis based on a little text exchange,

if the burner is trying to start - i.e. motor runs - then I don't suspect the primary control as the first defect.

If there is oil delivered but no flame I would look at

- a weak or failing ignition transformer

- improper electrode adjustment position or a cracked, shorting electrode

If the burner motor runs but no oil is delivered I'd look for a blocked nozzle, nozzle adapter, or a problem in the fuel unit itself

A more-orderly flow chart of diagnosing a non-starting oil burner is above on this page. Give that a look and let me know what you find as that'll help others.

Oil burner runs continuously, won't stop, doesn't fire-up

My oil burner, when started up, runs constantly without any change; there is no fire, and there is no attempt to turn off fire or ignition!

Would this be electrodes? (Jan 16, 2013) Burner Runs continuously

Reply: serious safety hazard: turn off the burner immediately!

Watch out: turn off the system immediately. When a fuel unit keeps pumping oil into the combustion chamber without ignition, later ignition can cause a dangerous puffback explosion.

(OIL BURNER SOOT & PUFFBACKS )

It sounds as if your oil burner safety controls are not working or have been bypassed. This is an unsafe heating system that needs repair by a trained service technician.

Sometimes my Beckett Oil Burner Won't Start

Becket Burner not starting under certain conditions. System is oil fire hot water baseboard with an indirect water heater. 3 zone system. I have a Becket AF, L8148A aquastat, R8184G cad cell relay.

Once the burner is started, it will cycle to the high limit and stop, reading 0 volts on C and B terminals of aquastat.

If Thermostat calls for heat and boiler is above 150-160 it will start and run correctly.

If the thermostat calls for heat and the boiler is below below 140 I get 120 volts across B and C terminals, the circulator turns on but the burner does not. If I push the reset button the burner starts, and runs up to temp.

Any suggestions, Aquastat or Cad cell relay? Thanks On 2022-01-18 by Alan

by Inspectapedia Com Moderator - Becket Oil Burner not starting

@Alan,

Start by checking the Aquastat settings to be sure they're correct and not "crossed" (HI too close to or even below the LO)

see AQUASTAT HI LO DIFF SETTINGS

by Alan

@Inspectapedia Com Moderator,

Thanks for the reply. Settings have never changed over 20 years. High is set at 185 and I dont believe there is a low.

I also occasionally get a variation as to what temp it shuts off at. Usually it is around 180-185, but once in a while it will stop at 10 - 150, and this morning shut off at 210. this was the highest I have seen it.

Could it be the aquastat thermocouple or something else?

by Inspectapedia Com Moderator

@Alan,

The temperature sending probe may be in poor thermal contact in the sensor well, or may be failing.

by Alan

@Inspectapedia Com Moderator, Thanks, appreciate the help.

Could the temp probe also cause the burner not to start when the boiler temp is low even though the thermostat calls for heat, the relay pulls in, the circulator is on and the aquastat b terminals read 120v but the burner does not kick on. (a reset start will turn on the burner)

by Inspectapedia Com Moderator - temperature sending probe may be in poor thermal contact

@Alan,

Probably not - though a defective probe could I suppose send a false "high temperature" reading.

The fact that your burner is going off on reset and that you have to push the reset button tells me that cleaning and/or adjustment or repair are needed.

Don't defer that service or you might risk not only loss of heat but a puffback explosion of incompletley-burned oil from sloppy starts or stops of the burner.

by Alan

@Inspectapedia Com Moderator, Thanks, I will go that route first.

Furnace oil burner motor runs but burner won't fire

Furnace motor starts but will not fire On 2021-12-18 by Pete

by Inspectapedia Com Moderator

@Pete,

There could be any of a number of causes of "no flame' at an oil burner, such as more-detailed causes of

• no fuel
• bad igniters or transformer

Step through the diagnostics on the page above and let us know what you find

Watch out: if oil is being delivered DO NOT keep pushing the reset button and trying to restart the oil burner as you could cause a dangerous PUFFBACK explosion

In the Recommended Articles or via our on page search box read OIL BURNER SOOT & PUFFBACKS

Sometimes my Aero oil burner won't re-ignite

I have an Qero burner on my hot water furnace. Starts and runs perfect most of the time.

Every once in a while it will not re-light I press the reset button, it might run perfect for a week or two, then one day it will not light.

I press the reset button again, the burner starts right up and runs perfectly, maybe for two days or two weeks again, then all of a sudden it will not light.

Any suggestions what to look for. - Joe Daye 12/3/11

Reply:

Intermittent problems are hard to track down, I admit, but usually when a system is limping along as yours is described, the operating problem is going to get worse. I'd look for an air leak in the oil piping, a dirty oil burner, a clogging filter, a draft problem.

Joe, take a look at the oil burner diagnostic suggestions beginning

at OIL BURNER INSPECTION.

Our oil burner only ignites if the door is open. What might be wrong.

We have replaced the electrodes and nozzle on the furnace.

It will only light with the door open and stay going after you close the door - seems like it is not getting enough air. What could be the problem? - Simone

Reply: combustion air shortage?

If you mean that the door to the boiler room (or furnace room) has to be open for an oil burner to work, that suggests it's air starved - we need about 1 sq. in. of air intake into a small utility room per 1000 BTUH for oil fired heating equipment - so a 90,000 BTUH oil heater would need 90 sq. in. of unfettered air intake opening. If you add louvers and screening the sq. in. requirement is increased.

Take a look at COMBUSTION AIR REQUIREMENTS

and COMBUSTION AIR for TIGHT BUILDINGS

But lack of combustion air usually leads to sooty operation and the oil burner going off on reset, or worse, loss of heat.

The bit about "... stay going after you close the door " is baffling.

If we don't have enough combustion air to ignite then we shouldn't have enough combustion air to keep going.

Watch out: I figure you need a service call from an expert heating service tech who will check the condition of the burner, combustion air setting, cleanliness of the flue vent connector and chimney, the draft, and a few other parameters.

Oil Burner Rapid Cycling blamed on Thermostat?

HVAC contractor says it the thermostat, not the furnace, but the thermostat folks say nothings wrong

Hi, I have an unusual and intermittent problem. The HVAC contractor says it the thermostat, not the furnace, but the thermostat folks say nothings wrong. I have oil burner with hot air heat and an eccobee 3 lite.

This has happened 2 nights in the past few week. The oil burner will come on and cycle off when the room temp is several degrees above the set point. The fan will not come on. Typically the fan will come on before the burner.

Last night while the thermostat was set to 60F and it was 64F in house, the oil burner started and stopped every 7-8 minutes.

When I moved the set point up above the temperature, everything worked fine, air handler came on and then the burner and heat worked fine.

Later in the night the program turned the thermostat back down to 60F and it started calling the burner in again when the temp was several degrees above the setting.

I turned the heat off on the eccobe and the burner still tried to turn on every 7-10 minutes with the heat off on the thermostat.

To summarize, the heat and fan seem to work fine when the temp is below the thermostat setting and the heat is supposed to come on.

The air handler always comes on first then the burner kicks in. However, sometimes when the room temp is several degrees above the thermostat set point and the heat should not come on, the oil burner is called, starts and runs for about 30 seconds.The air handler does not come on.

Last night this happened even when I turn the heat off on the eccobee thermostat. Thanks. On 2021-02-03 by Frank

Reply by (mod) -

Frank

That is an interesting problem involving the ecobee smart thermostat.

I'm not sure If I'm on the right track but certainly one thing I would want to eliminate would be a problem with the thermostat wires themselves such as an intermittent short or a loose or poor connection.

When you turn off heater thermostat and your heating system still turns itself on, it's entirely possible that that's because the thermostat wires are touching somewhere en route.

by Frank

Thanks. Shortly after I posed this question on here I pulled the eccobee thermostat and reset it and it did not happen again until today.

Same thing, but we came on several times when it wasnt supposed to and when I moved the call point up ot can on as it was supposed to. So frustrating. Guess I'll have to get HVAC folks out. Again.

Reply by (mod) -

@Frank,

Is the burner turning back on after it has shut off shortly after the thermostat was calling for heat?

If so then look for blocked air flow, dirty air filter, clogged heat exchanger, etc.

Oil Burner Short Cycling FAQs

Tip: see the oil burner diagnostic flowchart at OIL BURNER WONT RUN

Oil Furnace short cycles - I suspect the stack relay

Oil furnace short cycles for a bit, then will kick on as normal for a bit, then go back to short cycling.

Been through everything with this "A Christmas Story" type furnace, just hoping it's something simple that I'm overlooking.

It has an oil primary stack mount control, which looks ok. Thanks in advance. On 2020-12-09 by John

Reply by (mod) -

Watch the limit control dial - if the furnace is shutting off on the HI LIMIT then it's overheating - possibly a dirty air filter, blocked air flow in ductwork, even a bad sensor.

by John

Upon further review, it's starts and stops before the blower ever gets going... Would that still be a filter issue... Also, if it is the stack box, is there a quick fix there... Those things are hard to find and very expensive... Thanks again for the help! It's a Honeywell RA117A

by (mod) -

John

Probably not.

I was looking for the case in which the burner runs, plenum heats up, fan starts, air flow is too weak, plenum gets too hot, system shuts down.

your case is probably a burner cleaning and adjustment issue, or potentially a bad wire, connection, relay, or control board.

By "Stack box" and by your identification of your primary control as the Honeywell RA117A, you're referring to what I call a stack relay - a primary control that monitors temperature in the flue vent connector, detailed at

STACK RELAY SWITCH

You will want to take a look at that article because it describes re-stepping the relay control - it an be a bit finicky. Sometimes that's all that's needed to get the oil burner running properly again.

See

• STACK RELAY RESET BUTTON OPERATION
• STACK RELAY INTERNAL RE-STEPPING the CONTACTS

A stack relay is less reliable than a modern cad cell primary control, and can usually be replaced by a cad cell relay. There's a bit more to do - adding a cad cell eye and bracket in the burner assembly but any oil heat service tech ought to be able to do that.

Do me a favor and post a sharp photo of your stack relay as installed, and in a separate comment (one image per comment) a photo of the control with its cover removed.

Be sure to see the warnings and details in the article I cited above.

What to do if the 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.

Oil burner keeps cycling on and off

I had a oil condensing boiler installed end of March 2013.

It seems very sore on fuel, constantly cycling 3 minutes 'off' and 6 minutes 'on'

Is this normal? I will have burned 2800 lts of fuel in one year and I am only using my heating very sparlingly. i.e. average 8 hours a day. 5 single and 4 double radiators in small semi-detatched bungalow.

Would appreciate any advice. Bernard. (Feb 24, 2014) Bernard Mc Carron said:

Reply:

Bernard, I can't be very precise without knowing the installation, but the complaint you cite is surely worth investigating.

First, if the system were installed and working properly it would be very odd to cycle on and off indefinitely at a regular cycle as you describe. But we don't know if the problem is:

- a bad thermostat or other control

- a building with horrible heat loss

- a heating distribution system problem - not getting heat where it's wanted

It would make sense to call your service company, talk calmly with the service manager, and ask for a senior, experienced technician to inspect, test, and diagnose the system.

Oil Burner Trouble After a Service Call FAQs

Our oil burner ran fine until we had a service call

Our furnace was working fine until we had it cleaned. Now it runs fine for about 6 hours and then it shuts down. Furnace repair person has put on a new cycle controller but it still shuts down after 6 hours.

What do I do now ? On 2016-12-21 by Reuben A. Larson

by (mod) re: ask the oil heat service company for an experienced tech

Reuben

I'd call the service manager and politely ask for a senior, experienced service tech to diagnose what has gone wrong.

 

Oil Burner Runs When There is No Call for Heat

Oil furnace comes on even when room temperature is above the thermostat setting

My fuel oil furnace works with thermostat but will come on even when temp is above the setting.

The burner and pump run for 60 seconds a few times an hour even when not needed.

I put on a new filter, nozzle and flushed the oil lines. Still does it, any ideas? On 2015-12-23 by Jeremy

Reply by (mod): step by step diagnostics for a boiler or furnace that comes on when there is no call for heat.

Jeremy,

A failing control, temperature sensor at the heater or even shorting thermostat wires can cause intermittent boiler or furnace operation,.

The things you repaired are good to do but don't address the controls for the system.

If what you're calling a furnace (forced warm air heat) is actually a hot water heating boiler (hydronic heating) then

I'd start by reviewing the aquastat settings at AQUASTAT HI LO DIFF SETTINGS.

Then look more thoroughly at your boiler and your domestic hot water system. If your heating boiler is also being used to provide domestic hot water, say via tankless coil or by an indirect water heater, those uses can also cause the oil burner to run even though there's no call for heat.

Also review the diagnostics at CIRCULATOR PUMP RUNS INTERMITTENTLY. 

If your heat is truly a furnace (warm air heat), then see the step by step diagnostics

at DIAGNOSE & FIX FURNACE PROBLEMS 

Have to press the oil burner reset button once a week - techs can't find the problem

About once a week the burner shuts off and the reset has to be pressed. Burner will be good for about a week or so then same situation. Repair specialists can't seem to find the problem....any suggestions? On 2015-02-07 by Frank

Reply by (mod):

Frank I can't be smarter than the on-site repair people as they can see things that you or I don't.

But you might check for

- dirt, debris, water in the oil tank or piping or filter or pump screen

- a loose electrical connection

- a failing cad-cell sensor or relay

- an improper oil burner nozzle choice or oil leaks around the nozzle adapter

- an air leak in the system or any other operating problem that causes sooting at the burner nozzle assembly

IN short, when the system has shut down it'd be instructive to inspect it with care at that time as well as when the re-start is attempted.

Watch out: the problem you describe can lead to a dangerous puffback explosion if unburned fuel accumulates in the combustion chamber.

Keep me posted on what you find.

What causes oil flow to the oil burner to be intermittent?

my oil fired boiler has intermittent oil flow. I found this out when bleeding the line to the boiler the flow would be strong then stop with no sound of air passing through

. I have replaced the nozzle, pump, and motor I also have a hot water tank that shares the same oil line and it works just fine. Any ideas what this might be? On 2014-03-22 by Luis

by (mod) -

Luis when I see intermittent oil flow I

First check for a dirty oil filter or filter screen at the fuel unit

Next check that oil flows freely from the oil tank to the fuel unit - if not I blow out or replace the oil line and if needed the valve.

If the oil tank has a lot of sludge and especially if the oil line pickup is off of the bottom of the tank, then intermittent clogging will be recurrent.

I sometimes get past this by installing a new larger diameter oil line and doubled or larger capacity oil filters at the oil burner, or better, by re-piping to pick up oil coming in from the top of the oil tank.