From Newsgroup: alt.home.repair

My Beckett burner has begun acting strangely. Basically, it comes on
but before long, it starts to thump or boom. I immediately shut it off.
I think what might be happening is that fuel is entering the chamber,
but not always igniting, so there might be a slight build up causing the booms.

The burner had seen very intermittent use over the last seven years,
maybe used ten hours per winter. This winter though it was used much
more.

First step was to change out the nozzle. Still no change. I'm going to change the oil filter and check the CAD cell next.

Any info welcome.

Thank you,
JR
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From Newsgroup: alt.home.repair

On Sun, 1 Mar 2026 06:52:37 -0500, JR Dolobson <dolob55J@erols.net>
wrote:

My Beckett burner has begun acting strangely. Basically, it comes on
but before long, it starts to thump or boom. I immediately shut it off.
I think what might be happening is that fuel is entering the chamber,
but not always igniting, so there might be a slight build up causing the >booms.
The burner had seen very intermittent use over the last seven years,
maybe used ten hours per winter. This winter though it was used much
more.
First step was to change out the nozzle. Still no change. I'm going to >change the oil filter and check the CAD cell next.
Any info welcome.
Thank you,
JR

Our 20 year old furnace needed to be reset a couple times
at the start of the heating season - had us a little worried -
but when we filled the oil tank it worked fine again ..
We wondered if the oil level float guage was a little off ..
John T.
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From Newsgroup: alt.home.repair

On 3/1/26 8:16 AM, hubops@ccanoemail.com wrote:

On Sun, 1 Mar 2026 06:52:37 -0500, JR Dolobson <dolob55J@erols.net>
wrote:

My Beckett burner has begun acting strangely. Basically, it comes on
but before long, it starts to thump or boom. I immediately shut it off.
I think what might be happening is that fuel is entering the chamber,
but not always igniting, so there might be a slight build up causing the
booms.
The burner had seen very intermittent use over the last seven years,
maybe used ten hours per winter. This winter though it was used much
more.
First step was to change out the nozzle. Still no change. I'm going to
change the oil filter and check the CAD cell next.
Any info welcome.
Thank you,
JR

Our 20 year old furnace needed to be reset a couple times
at the start of the heating season - had us a little worried -
but when we filled the oil tank it worked fine again ..
We wondered if the oil level float guage was a little off ..
John T.

Today finished up with changeout of the oil filter and checking the CAD.
The CAD appeared fine, not cloudy, and the circuit board easily seen.
Primed the system before starting. Oil seemed clean and running. Start
up and within a minute, a smaller boom and then a slightly larger one.
I immediately shut it down once again.

Next steps?
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From Newsgroup: alt.home.repair

On Mon, 2 Mar 2026 01:29:12 -0500, JR Dolobson <dolob55J@erols.net>
wrote:

On 3/1/26 8:16 AM, hubops@ccanoemail.com wrote:

On Sun, 1 Mar 2026 06:52:37 -0500, JR Dolobson <dolob55J@erols.net>
wrote:

My Beckett burner has begun acting strangely. Basically, it comes on
but before long, it starts to thump or boom. I immediately shut it off. >>> I think what might be happening is that fuel is entering the chamber,
but not always igniting, so there might be a slight build up causing the >>> booms.
The burner had seen very intermittent use over the last seven years,
maybe used ten hours per winter. This winter though it was used much
more.
First step was to change out the nozzle. Still no change. I'm going to >>> change the oil filter and check the CAD cell next.
Any info welcome.
Thank you,
JR

Our 20 year old furnace needed to be reset a couple times
at the start of the heating season - had us a little worried -
but when we filled the oil tank it worked fine again ..
We wondered if the oil level float guage was a little off ..
John T.

Today finished up with changeout of the oil filter and checking the CAD.
The CAD appeared fine, not cloudy, and the circuit board easily seen.
Primed the system before starting. Oil seemed clean and running. Start
up and within a minute, a smaller boom and then a slightly larger one.
I immediately shut it down once again.

Next steps?

Dozens of youtube videos out there - perhaps one of them
will provide some help - these are just a few examples :

https://www.youtube.com/watch?v=mGGiOJ3GW6g

https://www.youtube.com/watch?v=Pdqfmc23mNc

https://www.youtube.com/watch?v=AAJXXVgx1MA

John T.
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From Newsgroup: alt.home.repair

On 3/2/26 2:54 AM, hubops@ccanoemail.com wrote:

On Mon, 2 Mar 2026 01:29:12 -0500, JR Dolobson <dolob55J@erols.net>
wrote:

On 3/1/26 8:16 AM, hubops@ccanoemail.com wrote:

On Sun, 1 Mar 2026 06:52:37 -0500, JR Dolobson <dolob55J@erols.net>
wrote:

My Beckett burner has begun acting strangely. Basically, it comes on
but before long, it starts to thump or boom. I immediately shut it off. >>>> I think what might be happening is that fuel is entering the chamber, >>>> but not always igniting, so there might be a slight build up causing the >>>> booms.
The burner had seen very intermittent use over the last seven years,
maybe used ten hours per winter. This winter though it was used much
more.
First step was to change out the nozzle. Still no change. I'm going to >>>> change the oil filter and check the CAD cell next.
Any info welcome.
Thank you,
JR

Our 20 year old furnace needed to be reset a couple times
at the start of the heating season - had us a little worried -
but when we filled the oil tank it worked fine again ..
We wondered if the oil level float guage was a little off ..
John T.

Today finished up with changeout of the oil filter and checking the CAD.
The CAD appeared fine, not cloudy, and the circuit board easily seen.
Primed the system before starting. Oil seemed clean and running. Start
up and within a minute, a smaller boom and then a slightly larger one.
I immediately shut it down once again.

Next steps?

Dozens of youtube videos out there - perhaps one of them
will provide some help - these are just a few examples :

https://www.youtube.com/watch?v=mGGiOJ3GW6g

https://www.youtube.com/watch?v=Pdqfmc23mNc

https://www.youtube.com/watch?v=AAJXXVgx1MA

John T.

Thanks. I don't think its the CAD. I decided to start it up again a
little while ago while this time observing the flame. The flame seems
to ignite as it should but then about 30 sec in, I start getting the
booms. Not sure if flame related as I shut the door and immediately
turn off. So, there does appear to be ignition or there'd be no steady
flame for the first 30 sec
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From Newsgroup: alt.home.repair

On Mon, 2 Mar 2026 05:11:17 -0500, JR Dolobson <dolob55J@erols.net>
wrote:

On 3/2/26 2:54 AM, hubops@ccanoemail.com wrote:

On Mon, 2 Mar 2026 01:29:12 -0500, JR Dolobson <dolob55J@erols.net>
wrote:

On 3/1/26 8:16 AM, hubops@ccanoemail.com wrote:

On Sun, 1 Mar 2026 06:52:37 -0500, JR Dolobson <dolob55J@erols.net>
wrote:

My Beckett burner has begun acting strangely. Basically, it comes on >>>>> but before long, it starts to thump or boom. I immediately shut it off. >>>>> I think what might be happening is that fuel is entering the chamber, >>>>> but not always igniting, so there might be a slight build up causing the >>>>> booms.
The burner had seen very intermittent use over the last seven years, >>>>> maybe used ten hours per winter. This winter though it was used much >>>>> more.
First step was to change out the nozzle. Still no change. I'm going to >>>>> change the oil filter and check the CAD cell next.
Any info welcome.
Thank you,
JR

Our 20 year old furnace needed to be reset a couple times
at the start of the heating season - had us a little worried -
but when we filled the oil tank it worked fine again ..
We wondered if the oil level float guage was a little off ..
John T.

Today finished up with changeout of the oil filter and checking the CAD. >>> The CAD appeared fine, not cloudy, and the circuit board easily seen.
Primed the system before starting. Oil seemed clean and running. Start >>> up and within a minute, a smaller boom and then a slightly larger one.
I immediately shut it down once again.

Next steps?

Dozens of youtube videos out there - perhaps one of them
will provide some help - these are just a few examples :

https://www.youtube.com/watch?v=mGGiOJ3GW6g

https://www.youtube.com/watch?v=Pdqfmc23mNc

https://www.youtube.com/watch?v=AAJXXVgx1MA

John T.

Thanks. I don't think its the CAD. I decided to start it up again a
little while ago while this time observing the flame. The flame seems
to ignite as it should but then about 30 sec in, I start getting the
booms. Not sure if flame related as I shut the door and immediately
turn off. So, there does appear to be ignition or there'd be no steady >flame for the first 30 sec

google AI info - use at own risk :-)


A Beckett oil burner that ignites"booms" (rumbling or puffing sound),
and then shuts down is experiencing a safety lockout, often caused by
delayed ignition or improper combustion. The boom sound indicates a
small explosion of accumulated fuel, and the shut-down is a safety
feature (often triggered by the cad cell sensor) to prevent further
danger
.a
Common Causes for "Ignite then Boom/Lockout" on Beckett Burners:
Delayed Ignition (The "Boom"): This is caused by a slight delay
between the oil spray starting and the spark igniting it, allowing oil
vapor to build up in the chamber. When it finally lights, it causes a
"boom" or puff-back.
Ignition System Failure: Electrodes may be worn, dirty, improperly
spaced, or cracked, leading to a weak or delayed spark.
Dirty Nozzle/Burner Components: A clogged or worn nozzle can cause a
poor spray pattern, leading to improper ignition.
Cad Cell Sensor Issue: The flame sensor (cad cell) may be dirty or
failing, causing it to misread the flame and shut down the burner
(lockout).
Contaminated/Air in Oil Line: Air in the pump (needs bleeding) or poor
quality oil can cause unsteady combustion.
Blocked Flue/Chimney: If exhaust cannot escape, it causes pressure
issues.a

Troubleshooting Steps:
1. Reset and Observe: Push the red reset button once to see if it
starts. If it booms and shuts down again, it requires repair.
2. Bleed the Pump: Ensure there is no air in the fuel line (using the
bleed nipple on the pump).
3. Inspect Electrodes: Clean and check electrode settings.
4. Replace Nozzle: A worn nozzle is a very common cause of ignition
problems.
5. Clean Cad Cell: Wipe off the sensor to ensure it detects the flame properly.a
5.
Note: If the burner keeps booming, it is highly recommended to call a professional, as repeated "booms" can damage the heat exchanger and
pose a safety risk.a

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