burner shut-down

plazo

I had trouble with my oiler burner at the end of last season - the burn reset kept opening. Over the summer, I replaced the oil filter and pump screen, happy that it ran trouble free for a month so far this season. But it’s happening again…

Burner always starts up great when the reset is pushed - seems no problem with transformer or electrodes, or fuel supply, so I sat with it this time. It sounded like a good, normal burn for about 10 minutes until the reset button popped for no apparent reason and shut it down again.

What would cause a burner reset in the middle of a normal burn? I thought the primary control/cad cell only operated to verify initial ignition…could the primary be faulty?

Appreciate thoughts and advice...

ChasMan

Sorry wrong thread...

Steamhead

Oil burners don't have internal fuses.

They do, however, have photoelectric "cad cells" to detect the presence of a flame. It's possible the cell is going bad, or the socket it plugs into is not making contact.

These parts aren't readily available, and one would need to make sure that's actually the problem. Time to call a pro. Where are you located?

Jamie Hall

And to clarify the OP's confusion -- it is a continuous sensing, not just at ignition. If the Cad cell is going, or the socket, and it decides there isn't any flame, it's going to shut the pump down to avoiding flooding the boiler with oil, which is never good...

HVACNUT

Can you post a pic of the primary control?
Cad cell eye is clean and tight connections? Are you able to ohm out the eye?
Where's the oil tank? Top fed? Bottom fed gravity?
It's possible the oil line is restricted and the longer the burner runs, it increases the vacuum to the point where it's out of the cad cell ohm range.

plazo

thanks for the insights -
- I did wipe off the cad cell, but didn’t test it (makes sense that it always needs to see the flame-I didn't realize until mentioned!)
- oil feed is from the bottom, tanks are indoors, about 10’ away.
- filter, body are new (I read here last year to check the filter - despite 20yrs of annual services, nobody noticed the body was installed backwards and with compression fittings … I can’t imagine the filter element was ever changed because the bleeder was on the wrong side...)
- fuel line is covered in cement on its run from tanks, so it's hard to see any potential damage
- when firing, flame looks good (boiler sounds like it always has … which might not be a scientific description!). I sat with it ... no sputtering, just it's normal, healthy roar until 10mins in, when the red button popped up...
- no puff-back or smoky smells on initial fire up, so I assume no unburned fuel is ever in the chamber
- earlier this season, it ran a month like a champion - no problems until today...
- Primary control is Honewell, but about 20 years old - here's a pic:

HVACNUT

Try this. Shut it down. Close the firomatic valve near the fuel pump. Remove the pump cover, with something under to catch the oil. Open the firomatic valve. Oil should flow out of the pump cover like Niagara falls. If it's just a trickle, the oil line is clogged.
That's also a 45 second safety intermittent primary and old tar ignition transformer. Intermittent meaning there's spark the whole time the burner runs.
Look into a 15 second safety interrupted ignition primary and a 14,000 volt solid state igniter. Once flame is established, the igniter drops out of the circuit as its not needed for the duration of the burner run time.

plazo

Thanks HVACNUT -

(I accidentally did part 1 already, but by disconnecting fuel line from the pump cover… thinking the fire valve was off….but yes a fuel fountain!) Pump screen is new … the bled-out fuel looks clean.

I will look into installing a more modern igniter, as you suggested.

HVACNUT

> @plazo said:
> Thanks HVACNUT -
>
> I will look into installing a more modern igniter, as you suggested.

And 15 second interrupted ignition primary. Maybe you should call a pro so a proper combustion analysis can be done. Try the "Find a contractor in my area" link at the top of the page.