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Air in oil line oil heater

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paulmars
paulmars Member Posts: 87
See pic. That is my current setup that gets air when i bleed it. Less then 1 second of tiny bubbles shortly after i open bleed port. Heater never cycled off for 45 minutes as i bleed it over and over. If the bleed was closed < 20 seconds, then no bubbles, but if it was open >30 seconds, there was tiny bubbles,but for less then 1 second. Several times I had it open for 30 to 45 seconds after bubbles stopped and never saw any more. Until i closed it for 30 or more seconds.

Pic https://ibb.co/h1PHNhH

Ideas?

Comments

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,840
    edited February 19
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    Not quite understanding your question/problem?
    Are you saying that you are performing a test using a bucket of oil. then you are getting some pockets of tiny air bubbles (almost like a batch of micro-bubbles that form a fog in the oil flow) then you get clear oil? for up to 30 seconds then the bubbles again? Does this problem cause a no heat condition when connected to the regular oil line?
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • paulmars
    paulmars Member Posts: 87
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    Problem with air in line. Was going to replace entire line, but 1st i did this and replaced flair fitting on pump too.

    Ignore syphon in fuel bucket. Copper tubing goes into fuel and syphon is not used.

    Bubbles dont start again until i close, then open bleed port again.
  • paulmars
    paulmars Member Posts: 87
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    Im getting heat, but it started sooting. We thought it was pump, but found bubbles and decided to replace entire line, but i did this test 1st
  • Intplm.
    Intplm. Member Posts: 1,961
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    Look to where the fuel is coming from.
    If the suction side is not fully emersed in the fuel, you can get air mixed with the oil.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,840
    edited February 19
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    paulmars said:

    Problem with air in line. Was going to replace entire line, but 1st i did this and replaced flair fitting on pump too.
    Bubbles dont start again until i close, then open bleed port again.

    Bubbles are usually a leak in the fuel line. Rarely they can be caused by excess vacuum.
    Are you still getting the same bubble issue with the test setup as you did with the line from the tank? Looks like the tank fuel line comes from overhead. Is the tank above the burner?

    Is the tank at the same level, or below the burner? From there does the fuel line runs up to the ceiling then comes back down from the ceiling to the burner?
    paulmars said:

    Im getting heat, but it started sooting. We thought it was pump, but found bubbles and decided to replace entire line, but i did this test 1st

    Sooting is rarely an issue related to air in the fuel. Sooting is insufficient combustion air mixing with the atomized fuel droplets in the combustion chamber. Do you have a combustion analyzer and a smoke tester?
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • paulmars
    paulmars Member Posts: 87
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    Problem with air in line. Was going to replace entire line, but 1st i did this and replaced flair fitting on pump too.
    Bubbles dont start again until i close, then open bleed port again.
    Bubbles are usually a leak in the fuel line. Rarely they can be caused by excess vacuum. Are you still getting the same bubble issue with the test setup as you did with the line from the tank? Looks like the tank fuel line comes from overhead. Is the tank above the burner? Is the tank at the same level, or below the burner? From there does the fuel line runs up to the ceiling then comes back down from the ceiling to the burner?
    Im getting heat, but it started sooting. We thought it was pump, but found bubbles and decided to replace entire line, but i did this test 1st
    Sooting is rarely an issue related to air in the fuel. Sooting is insufficient combustion air mixing with the atomized fuel droplets in the combustion chamber. Do you have a combustion analyzer and a smoke tester?
    The Tank is out of the circuit in my test setup. Otherwise line from tank goes up 8', across 24, then down 5'. That test line is off a new purchase 50' roll. Smoke test is 0 to 1 after 20 minutes run time. It's 8 to 10 smoke 5 minutes after startup. 

    For this test I replaced the pump flare fitting with new. Im always reluctant in tightening for fear of over tightening. It is quite tight, but i could get another 1\4 or even 1\2 turn, but if i turn it any more, ill need to do one full complete turn and i fear that would be over tightening and may be even be possible. I did cover threads with dope and let it sit after tightening for 48 hours before turning heater on. If it is pulling in air it only does for under 1 second. Maybe by opening bleed port im reducing the pressure differential and that stops air from being pulled in. Another words it might be pulling in air continually when bleed port is closed.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,840
    edited February 20
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    The Tank is out of the circuit in my test setup. Otherwise line from tank goes up 8', across 24, then down 5'. That test line is off a new purchase 50' roll. Smoke test is 0 to 1 after 20 minutes run time. It's 8 to 10 smoke 5 minutes after startup.


    Is this the same result for the smoke test on the original fuel line from the tank AND from the test bucket?
    #8 smoke after 5 minutes of operation, then a clean fire after 20 minutes of operation?

    Sounds like there is fuel finding its way into the chamber during down time. That extra fuel is burning with the fuel from the nozzle. After 20 minutes, all that fuel that leaked in during the burner off time has burned away, leaving only the oil from the nozzle to burn with the proper combustion air mixture from the burner fan.

    For tightening the flare nut on to the flare fitting here is the specifications
    From this publication https://issuu.com/n_anari/docs/refrigeration-flare-fittings-and-copper-tubing. Pipe No sealant or lubrication is needed on this connection because the flare is designed to make the flared copper tubing mate with the male side of the flare fitting with a metal to metal seal that is leak proof.

    Regarding the tapered threads of piping and fittings with the designation of NPT (the side of the fitting that goes into the fuel pump)I found this information:

    As a general rule, fittings with tapered pipe threads (NPT) should not be assembled to a specific torque because the torque required for a reliable joint varies with thread quality, port and fitting materials, sealant used, and other factors. (Source: Parker Hannifin Catalog 4300 Port End Assembly, page T7)

    Leakage path through NPT threads occurs between the very peaks of one thread and the very valley of the opposing thread. No matter how tight you make NPT threads, a leakage path still exists. It is the function of the sealant to block the path between the male and female thread.

    The article goes on the state:

    Most screwed piping is tightened until it feels "right" and the fitting is pointing in the desired direction. What the experienced mechanic is often "feeling" is how the fitting is getting tight. Screw it into until it starts to seat. Then up the force a little by yanking. If each yank gives less movement, you probably have a sound joint. If the movement stops suddenly, you have probably bottomed out. The experienced plumber knows when to stop before he damages the fitting or boss. Caution is advised, tapered pipe fittings into an aluminum boss as excessive torque can crack the boss. This is especially true when using Teflon tape because the low friction of Teflon makes it easy to over-tighten.


    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • paulmars
    paulmars Member Posts: 87
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    I think my single fitting is fine. Ive read a lot on tightening flair and npt. Most sites say different things. Ive never had a leak up until this issue i now have we suspected a joint leak. Now all joints are removed but one and i used all new parts and one of those fancy new type flair tools.

    Yes this is same as before concerning very smoky reducing to a good burn after 15-20 minutes.im sure it is drip. Maybe pump is sucking in air. I open chamber port and much smoke slowly reducing over time. I might tighten npt a bit and if that dont help, what else could it be besides bad pump.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,840
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    What does the inside of the oil burner fan housing look like? The fuel pump shaft seal may be the source of the leak. That test is done with a vacuum gauge.
    1. Make sure the fuel pump has oil in it.
    2. Make sure the bypass in the pump is not plugged. If you have a 2 pipe system, remove the return line and remove the bypass plug and plug the return line port with pipe dope and a 1/4" plug
    3. Install a vacuum gauge in the inlet port of the pump
    4. operate the pump and watch the vacuum gauge drop to 15" Hg when you open the bleeder.
    5. AT 15" Hg vacuum shut off the bleed port. The vacuum should for 10 minutes.
    6. If there is a leak in the gasket of pump seal or any of the other ports on the pump, then vacuum will drop in short order.

    If the oil supply tubing is not leaking, and you cant get a good vacuum test on the pump, you should think about replacing the fuel pump.

    Was that not your first question on your other post anyway?
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • paulmars
    paulmars Member Posts: 87
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    Yes we almost replaced pump cuz some thought shutoff pressure didn't hold properly so I was getting after drip. Suntec and rw beckett said it was ok, so it was then  suggested to see if air was getting in on low side which it was. So I might need a new pump but for a different reason.
  • paulmars
    paulmars Member Posts: 87
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  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,840
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    Seems like you have been wrestling with problem for some time. And you are going the DIY route. With this in mind, Would you be interested in what I would do in your situation? Since I would do it myself in my own home... and I have the experience of solving many customer problems.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • paulmars
    paulmars Member Posts: 87
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    Well ive been reading your replies and taking some of your advice so far. So yes. Also look at that nozzle line as i rcvd it from supply house. That dont look good to me. I have not used it yet.
  • paulmars
    paulmars Member Posts: 87
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    I did buy that nozzle line along with a new pump and 50' of copper, new flair tool, and more fittings. I figured that if the new line & fillings dont work, it must be pump. And if I didn't need pump, ill hold it in case i ever do. No heat suks.
  • paulmars
    paulmars Member Posts: 87
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    Btw that beckett fan. It is very easy to turn by hand,but no matter how fast i spin it, it stops immediately when i let go. Should it free spin at all?
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,840
    edited February 20
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    Tiger Loop Ultra will eliminate air in the fuel, and has a 10 Micron filter
    Tiger Loop flex hose for the pump to tiger loop connection
    New A2VA 3006B Fuel pump
    the necessary fittings to connect to same.



    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    Jon_blaney
  • paulmars
    paulmars Member Posts: 87
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    I shouldn't try and find the cause? It's work fine since i bought house in 1986.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,840
    edited February 21
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    @paulmars, When I have a suspicion that a nozzle line may have an after drip, I connect it to the high pressure line out of the burner. I place it in a downward orientation with a glass jar (like a pickle jar) so I can watch the nozzle spray and look for drips leaking form a source other than the nozzle orifice. then I operate the burner. Sometimes I see the after drip only. Sometimes I see a drip from the threaded connection between the nozzle and the nozzle adaptor. Sometimes I see the drip from the 1/8" pipe the the nozzle adaptor. Sometimes I see the flare connection leak at the 3/16" copper to the 1/8" pipe.
    That may be the next step.

    In business, you have to make executive decisions sometimes to get the customer happy. After 3 visits with no resolution, I will install the parts that the customer says they can't afford, Just to prove my point. Then I will return in a week to see how the repairs went. At that point I will ask the customer if they want to pay for the repairs (including the parts and labor) or do they want me to take my parts back that they can't afford and leave them operating with the original problem parts. Never has anyone refused to pay for the needed repairs.

    They just didn't want to pay for ANOTHER unsuccessful repair. (Sometimes I was the third guy in, sometimes I was the one with the three failed attempts.). I was confident that the repair would solve the problem so I took the chance that the customer would not stiff me for the repairs and not let me back after the successful repair.

    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • Grallert
    Grallert Member Posts: 644
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    That looks like a double flare? You shouldn't need to do that. Check the pump shaft seal. Does sound like there is fuel, excess fuel getting into the system. Bubbles: I'd have to see them to decide if I was worried about them or if They are the cause of the high smoke numbers.
    Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,840
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    This looks like a leaker



    I don't think it is the tool

    I think it is the prep.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    Grallert
  • paulmars
    paulmars Member Posts: 87
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    Yea. Supplyhouse sent that.  rw beckett nozzle p\n 5394. I ordered it, but didnt think it would look like that. 
  • paulmars
    paulmars Member Posts: 87
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    Supply house sending another nozzle line 5394. I bought that and a pump but haven't used either yet.

    Today I tightened fitting more. Now running for 30 seconds with no bubbles, then his for a few seconds. Then bubbles stopped (2nd pic), then bubbles again.

  • paulmars
    paulmars Member Posts: 87
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    "Sooting is rarely an issue related to air in the fuel. "

    I thought i was told that air in line would make after drip. Well i do have both.

    "Leakage path through NPT threads occurs between the very peaks of one thread and the very valley of the opposing thread. No matter how tight you make NPT threads, a leakage path still exists. It is the function of the sealant to block the path between the male and female thread."

    Ive read the opposite many times. That dope is not to seal, it is to make tightening easier.

    I saw a drop of oil still in the fitting when i removed it in Dec 2023. Then i replaced the fitting and still get afterdrip.
  • paulmars
    paulmars Member Posts: 87
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    That the taper is to seal ive read.
  • HVACNUT
    HVACNUT Member Posts: 5,841
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    Get an inline vacuum gauge and you can see what's going on while the burner is running. 
  • paulmars
    paulmars Member Posts: 87
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    What might that tell me?
  • pell
    pell Member Posts: 22
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    Just looking at your picture of the open burner it clearly shows one of the cover bolts not fully tightened, hopefully you have corrected this. You pointed out that never had a problem since 1986, assuming you bought the home new this is 38 years old. As Ed suggested do the vacuum test. Chances are fittings/piping and or filter assembly are having wear. Do you have a manual type shut-off valve on the tank along with a firematic shut-off? This could be pulling in air. Also oil line from tank to burner should be blown out to remove any type of restriction that could be there. If it was me I would replace everything from tank to the fuel unit, with tiger loop. Then install new pump with solenoid and new primary control to give you the ability to control the pump and add pre/post purge.
  • paulmars
    paulmars Member Posts: 87
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    pell said:
    Just looking at your picture of the open burner it clearly shows one of the cover bolts not fully tightened, hopefully you have corrected this. You pointed out that never had a problem since 1986, assuming you bought the home new this is 38 years old. As Ed suggested do the vacuum test. Chances are fittings/piping and or filter assembly are having wear. Do you have a manual type shut-off valve on the tank along with a firematic shut-off? This could be pulling in air. Also oil line from tank to burner should be blown out to remove any type of restriction that could be there. If it was me I would replace everything from tank to the fuel unit, with tiger loop. Then install new pump with solenoid and new primary control to give you the ability to control the pump and add pre/post purge.
    one of the cover bolts not fully tightened?

    All fittings and pipes tank & filter & valves removed for this test
  • pell
    pell Member Posts: 22
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    Yes looking at your third pic (one with the ignitor opened up) clearly shows the top right pump cover screw hanging out about 1/8 of an Inch.
    EdTheHeaterMan
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,840
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    pell said:

    Yes looking at your third pic (one with the ignitor opened up) clearly shows the top right pump cover screw hanging out about 1/8 of an Inch.


    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,840
    edited February 23
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    I find this discussion [along with your other discussion about when to replace oil furnace shutoff solenoid ? which is basically about the same thing], is never going to get to a satisfactory conclusion.
    paulmars said:
    Problem with air in line. Was going to replace entire line, but 1st i did this and replaced flair fitting on pump too.

    paulmars said:
    Yes we almost replaced pump

    paulmars said:
    "Sooting is rarely an issue related to air in the fuel. "

    I thought i was told that air in line would make after drip. Well i do have both.

    "Leakage path through NPT threads occurs between the very peaks of one thread and the very valley of the opposing thread. No matter how tight you make NPT threads, a leakage path still exists. It is the function of the sealant to block the path between the male and female thread."

    Ive read the opposite many times. That dope is not to seal, it is to make tightening easier.

    I saw a drop of oil still in the fitting when i removed it in Dec 2023. Then i replaced the fitting and still get afterdrip.

    paulmars said:
    What might that tell me?

    paulmars said:
    one of the cover bolts not fully tightened?

    ...are just a few of the comments that indicate that your would rather run tests than actually fix the issue.
    If you want to really put this to bed, install that pump you purchased, install the fuel line you purchased,
    and follow the things that I would do in one of my previous comments that you replied to with:
    paulmars said:
    I shouldn't try and find the cause? It's work fine since i bought house in 1986.



    Well it is obviously not working now and from what I can see... You almost have the answer you are looking for... So be like Nike. Just do it!
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    GrallertIntplm.
  • paulmars
    paulmars Member Posts: 87
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    Yes looking at your third pic (one with the ignitor opened up) clearly shows the top right pump cover screw hanging out about 1/8 of an Inch.
    Yes looking at your toptical illusion hird pic (one with the ignitor opened up) clearly shows the top right pump cover screw hanging out about 1/8 of an Inch.
    Optical illusion. It is tight.
  • paulmars
    paulmars Member Posts: 87
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    Well it is obviously not working now and from what I can see... You almost have the answer you are looking for... So be like Nike. Just do it!
    Ive started, but waiting on shipment of 2 fittings.