Oil burner issues?

I have a Beckett Oil burner for my boiler. It hasn't been serviced in a couple years and last week it tripped the reset button. It restarted and ran another three days so I was hoping to make it to my day off and check it. It stopped running twice more and restarted both times. It stopped on Sunday and it would only run a minute or so after restarting. I left it  off and stayed at my girlfriend's. Today I replaced the fuel filter which was pretty dirty, but not the nozzle as I was sent the wrong one and can't get the right one locally until later this afternoon.  I bled it and it still E36 M3s off right away. What else should I be looking at?  

Does it have a thermocouple? If it's bad it may not recognize that the burner is lit and cut fuel. 

Edit to say, I tinkered with one a bunch of years ago that had an optical sensor to tell if the flame was burning. Maybe yours does as well and it needs to be cleaned. 

The capacitor on the motor might be shot (if it has one)

Looks like Beckett uses this guy.

In reply to Toyman! :

It has that, my next step will be swap it out. 

I know just enough about boilers to kill myself.  BUT, when this is over Wally, I would think about a service contract.  In the off season they clean it out, replace the oil spray nozzle (think dirty fuel injector) new oil filter and suck all the dust off the inside.  Furnace runs more efficiently AND as a contracted customer, you go to the top of the list in case of emergency vs someone cruising the yellow pages.

Good luck.

I need to find a different company for one. I got rid of my contract a few years ago, I had a controller go wrong. They came out, replaced it, and it wasn't covered in the contract so it was a $600 emergency call.  They didn't fix the water leak that killed the controller so the new one was burned out my morning. Luckily I figured out what happened and replaced the new one myself for $80. 

In reply to Wally (Forum Supporter) :

The ignition electrodes are a wear item as well, the cad cell that proves the flame to the flame safety control (what's in Toyman's picture) is something I used to replace annually when doing a PM.   The positioning of the electrodes is pretty specific, they put a nice gauge to set them to the proper gap and distance off the nozzle in the kit.   Link below may / may not be for your burner, check the burner nameplate.

Amazon.com: Beckett 5780 Electrode Insulator Assembly : Industrial & Scientific

OK these things are stone simple, typically if it kicks out its due to either a damaged or dirty CAD cell (the little light sensor thingy) or the ignition isnt actually firing consistently or the gap is too big.  Running a worn out nozzle will sometimes not start, and it will soot or burn extra fuel, but unless its totally junk or clogged it should still run with a worn nozzle.  

So first the troubleshooting.  Crack it open, replace the nozzle.  This is just for a PM, not really needed in most instances but nozzles are cheap and its good to have a new one before fixing everything else.  Note that there are different styles of nozzles and its furnace/combustion chamber specific.  RTFM and replace, no guarantees the one you took out is correct.

While its apart, look at the two electrodes that ignite the the fuel.  They should have pointed tips (like a pencil) and be gapped properly.  If they are worn out, replace them.  If you need to "get by" for a weekend, clean them good with brake cleaner and resharpen the tips with a grinder.  But replace them ASAP.  You don't  need need the Beckett gauge.  New electrodes come with the gauge but you can set it by eyeball and using a caliper or a few drill bits if you are handy.  Its just gotta be close, doesnt have to be micrometer-precise.  

To diagnose the CAD cell, jump across the wires and fire up the burner.  If it runs happy as can be and doesn't shut off until the thermostat commands it, you have a loose wire, dirty, or damaged CAD cell.  They rarely die, but it can happen.  You can also have a CAD cell giving a higher resistance if the flame is weak, you can check them with a multimeter.

Lastly, make sure the connections between the electrodes and the igniter are nice and clean.  Occasionally my igniter would fail to start, I would go clean the contact springs up with some brake cleaner and scotchbrite and put it back together and it would run for another year or 2.   

Then when you are all said and done, whip out your manometer and set the draft.

https://falconrme.com/wp-content/uploads/2019/06/Beckett-Diesel-Burner-Manual-English.pdf

https://www.acservicetech.com/post/troubleshooting-a-cad-cell-flame-detector-for-an-oil-burner

I had a similar issue a few years back. It would fire up and almost immediately shut off. Service guy came out, tested things, found the control box was bad, and replaced it (the thing on the right with the digital readout). 



About a month later, the issue resurfaced. After researching a bit online, someone said to check this jumper. 



Turns out, these work better when they are screwed all the way down so they can make constant contact. Who knew? 

It's run good since changing the eye this afternoon and cleaning the electrodes.  They're a little worn looking so I ordered a set and the correct nozzle. I also managed to lose my wallet last night so just going to the plumbing supply place wasn't happening and Home Depot didn't have them in stock.  Can't wait to see what else goes wrong.