Irregular lock outs

lib

Oil furnace, 2-line system, buried tank, furnace in crawl space.

I am not a handy woman. 

Furnace locks out periodically. I know only because it gets cold. No odd noises. Happens every few weeks or sometimes not for 3-4 months, almost an entire season. When it runs, runs well and doesn't use more oil than it ever did. Not especially dirty although its oil so...No odd noises when it starts, runs, or stops. 

Have best repair company for oil heat in area but no real solution. Unit is serviced at start of every season. 

Oil company is reputable, no local complaints (that I know of) of "dirty oil." Tank never less than 1/4 full. No water in tank per "gum test" on the stick. No water seen by techs except in Sept 2020 said there was rust in oil filter case. (Very humid here in summer though) Tank gum test negative. 

Replaced CAD cell

Replaced something expensive...maybe the primary ignition?

Replaced nozzle multiple times

Recalibrated, cleaned everything. Multiple times. 

Burner is said to run clean. Reset "flame" multiple times.

Fan seems to run fine. 

After lockout when reset, fires up immediately without tech doing anything but pushing reset. 

One tech said air in lines so hand dig down to tank and replace lines. ($$$$$ with no promises that's the problem) There's never been a need seen to bleed the lines although several techs said they did "just in case."

Another said tiger tail then decided it wasn't likely air.

One said it loses its prime. Thinks maybe air. Another said the problem is ignition maybe not a prime issue. Another said maybe the oil pump. Tech took it apart and cleaned. Reassembled. Ran furnace. Took it apart again. No issues found. 

Any ideas? Thanks so much

Jamie Hall

One key observation (thank you!): "After lockout when reset, fires up immediately without tech doing anything but pushing reset. ". If it starts right up, it's not losing prime (even with a modern control, that could take a minute or two to fire up -- with an older control, you'd have to reprime by hand. Which you don't).

So it's not the oil lines (no need to go digging), nor is it likely to be dirty oil or a dirty filter or water.

Which leaves pretty much a problem with the burner itself or the ignition. The burner is said to run clean, but has it been checked and adjusted with proper measuring devices? Or just "that looks pretty good"? You really need to have the test equipment and know how to use it to do a proper job of it.

STEVEusaPA

Could be any number of things.
All components can be properly checked by a competent tech with the proper tools and skills.
Important to figure out when it is failing.
After the second lockout, the tech could’ve put a modern primary like a Carlin ProMaxx that has plenty of on board diagnostics to help point them in the right direction, if they weren’t skilled enough.

EBEBRATT-Ed

Could very well be an oil line issue with the symptoms your having. Oil likes must be 100% air and vacuum tight.

A classic example of this is a burner that fails more often in the spring and fall when the burner runs less and has a chance to "drop it's prime" yet in cold weather it runs better because it cycles mor often and does not loose prime.

Where is your oil tank elevation wise compared to the burner? How long are the oil likes?

rick in Alaska

My money is on a fuel pump solenoid. I have had quite a few that run just fine, and then they don't. But by the time you get to the call, it has cooled off, and works again. My guess is it has internal electronics in it that gets hot during a run time, overheats, and shuts down. Then when it cools down again, it works again until the next time.
Put a new solenoid coil on it and I bet it will stop the problem.
Rick

lib

EBEBRATT-Ed said:

Could very well be an oil line issue with the symptoms your having. Oil likes must be 100% air and vacuum tight. A classic example of this is a burner that fails more often in the spring and fall when the burner runs less and has a chance to "drop it's prime" yet in cold weather it runs better because it cycles mor often and does not loose prime. Where is your oil tank elevation wise compared to the burner? How long are the oil likes?

It happens when it runs alot when it's unusually cold (one tech thought it was overheating and locking. Changed nozzle to spray less oil. No difference.)

And it happens when it hardly runs at all when it's warm (warm for winter) so another tech thought that's why it was losing its prime. Time between "on times" was so long air got in. But I started it in summer after not running it at all for 6 solid weeks and it started right up. 

The tank is underground. I don't know the elevation but the tank is higher than the furnace for sure given the general layout  The underground lines are pretty long... Maybe 25-30 feet? But they've always been that long and this didn't happen for 15 years. (I lived here) It's only the last 2 years that it's been an issue.. 
Thanks!

lib

Jamie Hall said:

One key observation (thank you!): "After lockout when reset, fires up immediately without tech doing anything but pushing reset. ". If it starts right up, it's not losing prime (even with a modern control, that could take a minute or two to fire up -- with an older control, you'd have to reprime by hand. Which you don't). So it's not the oil lines (no need to go digging), nor is it likely to be dirty oil or a dirty filter or water. Which leaves pretty much a problem with the burner itself or the ignition. The burner is said to run clean, but has it been checked and adjusted with proper measuring devices? Or just "that looks pretty good"? You really need to have the test equipment and know how to use it to do a proper job of it.

Thank you!  I thought it probably couldn't be a prime issue as it "recovered" immediately. But they said if there was air in the line, the oil could have close to where it needed to be but it didn't get **quite*" close enough to avoid shut down for safety reasons from (I think) the limit switch. But it was SO close, it would start up next time.

I think they've checked the burner and adjusted it with equipment but I will check.

Any chance if an intermittantly bad limit switch? Or whatever it is that locks it down? 

Thank you. 

lib

rick in Alaska said:

My money is on a fuel pump solenoid. I have had quite a few that run just fine, and then they don't. But by the time you get to the call, it has cooled off, and works again. My guess is it has internal electronics in it that gets hot during a run time, overheats, and shuts down. Then when it cools down again, it works again until the next time. Put a new solenoid coil on it and I bet it will stop the problem. Rick

Thank you! It doesn't only happen when it's really cold. Also happens when it's warm for winter. But I guess it may not take much for a pump to get hot. Thanks again. I'll suggest that. 

lib

STEVEusaPA said:

Could be any number of things. All components can be properly checked by a competent tech with the proper tools and skills. Important to figure out when it is failing. After the second lockout, the tech could’ve put a modern primary like a Carlin ProMaxx that has plenty of on board diagnostics to help point them in the right direction, if they weren’t skilled enough.

Thanks! After over 10 lockouts, I'd welcome the help of a "cheater" instrument for diagnosis. I'll try to suggest that.

lib

rick in Alaska said:

My money is on a fuel pump solenoid. I have had quite a few that run just fine, and then they don't. But by the time you get to the call, it has cooled off, and works again. My guess is it has internal electronics in it that gets hot during a run time, overheats, and shuts down. Then when it cools down again, it works again until the next time. Put a new solenoid coil on it and I bet it will stop the problem. Rick

Thanks! Answer is below for some reason. 

Big Ed_4

Ignition and oil line problems would be easy to spot . Fuel pump can be checked by increasing pump pressure when running . Flame would drop out . Primary and eye are new . Could be a solenoid if the burner has one or the older split phase motor could hold a dead spot . That can be checked with a OHM meter with the motor pulled off the chassis . Post a few photos of the burner , lets see what equipment is on site ...

SuperTech

Have the technician remove the capacitor from the burner motor and test it with a multimeter.  I have fixed a few intermittent oil burner problems by replacing the capacitor.  The Beckett motor usually uses a 20 microfarad capacitor,  I have found some that test at less than 10 MFD and the motor usually starts the majority of the time. Yesterday I replaced a Carlin burner motor that used a 16 MFD capacitor,  it tested at 9.6 MFD. Usually these capacitors should test out within 5 or 6 percent of the microfarad rating. 

EdTheHeaterMan

I hate when that happens!

If you were my customer, after the third time with no obvious solution I would install the Carlin ProMaxx suggested by @STEVEusaPA. I have been in your contractor's situation several times. The diagnostic controls were very helpful in resolving the issue. Once I discovered a low electric current condition at the ignition. Even though the ignitor tested fine every time I was there. The control found the problem after 456 cycles and again after 345 cycles. The customer was able to reset and get the heat back on while the error was stored in the control's memory. I replaced the ignitor and the problem was solved. I even offered to buy back the Carlin Primary control (since that was not the original problem) but the customer liked the digital display and elected to keep it.

This next part is a bit technical for the homeowner but will be interesting for the technical observers.

I did have one problem that was unable to be solved that we finally determined was what I called "Dirty Electricity." The problem was the electricity that was feeding the burner was experiencing "micro outages" That is the only explanation I could come up with. To resolve a different problem I replaced an analog primary control with a digital control. Soon after, there were nuisance lockouts. We looked at the above-ground fuel tank/Cold oil as the cause, then the fuel pump, finally I installed a Diagnostic Primary control. (Honeywell had just introduced one). For 2 years I could not figure out the problem. There were at least 10 nuisance lockouts over that time with no obvious cause. Even an electrician was called to check the home's electrical system. of course he found no issue with the electrical circuit

There were no other electronic issues in the home. No computer, alarm clocks, or microwave flashing any indication that the power failed. They even have a VCR that would flash "12:00" if the power went out. So no other electrical appliance in the home was indicating a power interruption. The diagnostic control was however showing the reason for the lockout. I can't remember what the reason was today but one of the causes for that code was a brief power outage. By brief, I mean less than a second. An analog control would have just kept running but the digital control recorded that as a reason to shut down the burner. If that happened three times during a call for heat cycle the burner would lockout.

I put the analog control back on and the lockouts stopped but the original issue (odors I believe) returned. Then I remembered that a Riello burner control operates on the "BACK EMF" electricity generated by the operation of the burner motor. That would isolate the digital electronics of the Riello control from the "DIRTY ELECTRIC" that was supplying the other controls. I installed the Riello burner for the customer with the explanation that if it did not solve the problem I would not charge him for the new burner, and put the original burner back. It has been 4 years since the Riello was installed and no nuisance lockouts.

Just to add insult to injury, the burner did lockout about 2 weeks after I installed it. Come to find there was no oil in the tank. We just had to laugh about that one.

For the homeowner, If you print this out and give it to the next technician who arrives to find the problem after they install a Carlin Pro Max, try a new pump solenoid and check the motor capacitor, This may be an option.


Hopefully, they won't be insulted and take the information from one of my experiences, and use it as another tool in resolving the oil burner problems.

Respectfully submitted,
Mr.Ed

EdTheHeaterMan

Big Ed_4 said:

Ignition and oil line problems would be easy to spot . Fuel pump can be checked by increasing pump pressure when running . Flame would drop out . Primary and eye are new . Could be a solenoid if the burner has one or the older split phase motor could hold a dead spot . That can be checked with a OHM meter with the motor pulled off the chassis . Post a few photos of the burner , lets see what equipment is on site ...

I'm thinking this homeowner is not going to crawl under the house to take some pictures.

STEVEusaPA

SuperTech said:

Have the technician remove the capacitor from the burner motor and test it with a multimeter.  I have fixed a few intermittent oil burner problems by replacing the capacitor.  The Beckett motor usually uses a 20 microfarad capacitor,  I have found some that test at less than 10 MFD and the motor usually starts the majority of the time. Yesterday I replaced a Carlin burner motor that used a 16 MFD capacitor,  it tested at 9.6 MFD. Usually these capacitors should test out within 5 or 6 percent of the microfarad rating. 

Are you able to source actual OEM capacitors, or just using off the shelf? RE Michel & Sids don't stock them.

Jon_blaney

It is the oil burner electrodes. Something happens when the get very hot. It only happens when the burner is in heavy use, cold weather.

lib

Big Ed_4 said:

Ignition and oil line problems would be easy to spot . Fuel pump can be checked by increasing pump pressure when running . Flame would drop out . Primary and eye are new . Could be a solenoid if the burner has one or the older split phase motor could hold a dead spot . That can be checked with a OHM meter with the motor pulled off the chassis . Post a few photos of the burner , lets see what equipment is on site ...

Unfortunately as @EdTheHeaterMan guessed, I'm not really able to take pictures. It's not just a matter of crawling under the house. There's a heavy lid to take off and then you drop down into a hole (a fairly deep hole you have to be able to get out of later like getting out of a pool without water) then crawl. I HAVE been under there. But not very recently. Now I'm in my late 60's and a wimp. But thanks for trying to help! I'll pass along your ideas.

lib

EdTheHeaterMan said:

Ignition and oil line problems would be easy to spot . Fuel pump can be checked by increasing pump pressure when running . Flame would drop out . Primary and eye are new . Could be a solenoid if the burner has one or the older split phase motor could hold a dead spot . That can be checked with a OHM meter with the motor pulled off the chassis . Post a few photos of the burner , lets see what equipment is on site ...

I'm thinking this homeowner is not going to crawl under the house to take some pictures.

Unfortunately you are right! ☺️

lib

Jon_blaney said:

It is the oil burner electrodes. Something happens when the get very hot. It only happens when the burner is in heavy use, cold weather.

Thank you. 

Could be. And of course, the furnace runs only in cold weather. But (fortunately) it doesn't seem to happen more often when it's unseasonably cold. (I'm in NC. Unseasonably cold means a string of nights in teens or low twenties vs 30s-40s.) Sometimes it happens when it's pretty warm-- like 50s daytime when it would be expected to run only every 3-4 hrs to keep it 69 inside. One tech thought it could be overheating and put a smaller nozzle in thinking it would get less hot. But that was last year and made no difference. 

lib

EdTheHeaterMan said:

I hate when that happens! If you were my customer, after the third time with no obvious solution I would install the Carlin ProMaxx suggested by @STEVEusaPA. I have been in your contractor's situation several times. The diagnostic controls were very helpful in resolving the issue. Once I discovered a low electric current condition at the ignition. Even though the ignitor tested fine every time I was there. The control found the problem after 456 cycles and again after 345 cycles. The customer was able to reset and get the heat back on while the error was stored in the control's memory. I replaced the ignitor and the problem was solved. I even offered to buy back the Carlin Primary control (since that was not the original problem) but the customer liked the digital display and elected to keep it. This next part is a bit technical for the homeowner but will be interesting for the technical observers. I did have one problem that was unable to be solved that we finally determined was what I called "Dirty Electricity." The problem was the electricity that was feeding the burner was experiencing "micro outages" That is the only explanation I could come up with. To resolve a different problem I replaced an analog primary control with a digital control. Soon after, there were nuisance lockouts. We looked at the above-ground fuel tank/Cold oil as the cause, then the fuel pump, finally I installed a Diagnostic Primary control. (Honeywell had just introduced one). For 2 years I could not figure out the problem. There were at least 10 nuisance lockouts over that time with no obvious cause. Even an electrician was called to check the home's electrical system. of course he found no issue with the electrical circuit There were no other electronic issues in the home. No computer, alarm clocks, or microwave flashing any indication that the power failed. They even have a VCR that would flash "12:00" if the power went out. So no other electrical appliance in the home was indicating a power interruption. The diagnostic control was however showing the reason for the lockout. I can't remember what the reason was today but one of the causes for that code was a brief power outage. By brief, I mean less than a second. An analog control would have just kept running but the digital control recorded that as a reason to shut down the burner. If that happened three times during a call for heat cycle the burner would lockout. I put the analog control back on and the lockouts stopped but the original issue (odors I believe) returned. Then I remembered that a Riello burner control operates on the "BACK EMF" electricity generated by the operation of the burner motor. That would isolate the digital electronics of the Riello control from the "DIRTY ELECTRIC" that was supplying the other controls. I installed the Riello burner for the customer with the explanation the if it did not solve the problem I would not charge him for the new burner, and put the original burner back. It has been 4 years since the Riello was installed and no nuisance lockouts. Just to add insult to injury, the burner did lockout about 2 weeks after I installed it. Come to find there was no oil in the tank. We just had to laugh about that one. For the homeowner, If you print this out and give it to the next technician who arrives to find the problem after they install a Carlin Pro Max, try a new pump solenoid and check the motor capacitor, This may be an option. Hopefully, they won't be insulted and take the information from one of my experiences, and use it as another tool in resolving the oil burner problems. Respectfully submitted, Mr.Ed

Hmmm. Could be. Lots of pines here and lots of above-ground power lines.. Lots of outages and blinks. However, never has happened with an outage and isn't related to "blinks" that would cause clocks/cable box to have to be reset. 

I understand you are talking about micro-outages. Undetectable except by the method you've described. But would micro-outages be a possible cause if actual outages and noticeable blinks aren't? 

Thanks!

lib

SuperTech said:

Have the technician remove the capacitor from the burner motor and test it with a multimeter.  I have fixed a few intermittent oil burner problems by replacing the capacitor.  The Beckett motor usually uses a 20 microfarad capacitor,  I have found some that test at less than 10 MFD and the motor usually starts the majority of the time. Yesterday I replaced a Carlin burner motor that used a 16 MFD capacitor,  it tested at 9.6 MFD. Usually these capacitors should test out within 5 or 6 percent of the microfarad rating. 

Will do. Thanks!

EdTheHeaterMan

@lib, I only shared that long story as a last resort. That "Dirty Electric" failure also depends on the type of primary control you have. And I don't expect you to know. Unless the part number was on an invoice or work order the only way to see is if one looked at it. My guess is that you don't have that problem. The Electronic ignition (or Ignition transformer) or the motor capacitor or the oil valve are all more likely. The Pro Maxx diagnostic control can help narrow it down.

Best wishes on your system.

Mr.Ed

lib

Thanks Mr. Ed!

EdTheHeaterMan

I'm wondering if this problem from last year was ever resolved?

STEVEusaPA

EdTheHeaterMan said:

I'm wondering if this problem from last year was ever resolved?

Why?

SuperTech

STEVEusaPA said:

Have the technician remove the capacitor from the burner motor and test it with a multimeter.  I have fixed a few intermittent oil burner problems by replacing the capacitor.  The Beckett motor usually uses a 20 microfarad capacitor,  I have found some that test at less than 10 MFD and the motor usually starts the majority of the time. Yesterday I replaced a Carlin burner motor that used a 16 MFD capacitor,  it tested at 9.6 MFD. Usually these capacitors should test out within 5 or 6 percent of the microfarad rating. 

Are you able to source actual OEM capacitors, or just using off the shelf? RE Michel & Sids don't stock them.

The only source of OEM capacitors I have are good ones taken off bad motors. I have a few of each from a flood recently that took out quite a few burner motors. I have used non OEM capacitors in a pinch in the past. It looks awkward but functions fine.