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Oil burner problem

Jim_18 Member Posts: 1
I have a problem with my oil burner. The problem is that when it shuts off it smokes and rumbles. They call it after burn or drip. A serviceman came and replaced the fuel pump about 2 months ago but its still doing the same thing. I called the oil company yesterday and another serviceman said that I have a suction leak I have an underground tank thats about 8 feet from the burner with 2 oil lines to the burner one supply and one returning to the tank. The second serviceman said that there were air bubbles in the oil and this was causing my problem. Before I have to dig up the oil lines or replace the tank with an above ground tank I want to be sure thats the problem. Any input would be appreciated. Thank You


  • Tony_8
    Tony_8 Member Posts: 608
    save the shovelling

    Never heard of a suction leak causing after-burn. Usually, it's caused by incomplete combustion when running. Leftover fuel in the chamber burns off w/o enough air for proper combustion and rumbles/smokes. Change the nozzle, making sure it's the correct one according to your manual. Check the nozzle line for cracks/leaks. Check the end of the gun to make sure it's all there (no irregularities). Then set it up w/ an instrument in the hands of a qualified serviceman. If it's not a retention head burner, save some fuel and get one.
  • Frank_17
    Frank_17 Member Posts: 107

    I've seen draft cause this. Be sure the draft is set correctly. (often overlooked and under estimated by techs)
    sloenoid valves may be an option if it is the pump , tiger loop may help if it is air.
    DEP still allows an old underground tank ????
  • Firedragon_4
    Firedragon_4 Member Posts: 1,436
    Have them install a solenoid valve on the pump,

    or a Beckett Clean-Cut pump, if that doesn't fix it call another company!
  • Doug Oest
    Doug Oest Member Posts: 34
    Heard of this one plenty

    All these comments are good ones. I have heard the Tiger Loop working very well. If you want to try and isolate the oil delivery system from the burner, try using a 5 gallon bucket for a little bit. In other words, disconnect the oil lines from the buried tank and just leave them there capped off. Then, take a 5 gal bucket and keep it filled. You'll have to convert the pump back to a single pipe arrangement by installing the by-pass plug in the pump.

    If it runs ok this way, you know the problem is in the oil delivery system.

    Another good check is to put a vacuum gage on the pump. There are several checks you can perform to see if the check valve in the pump is doing what it is suppose to do.

    I would consult the burner manufacturer to see what the vacuum readings should be. If your a homeowner, I would say its best to leave this stuff to your heating guy.
  • Tom M.
    Tom M. Member Posts: 237
    a small suction leak can cause afterburn

    Air mixed in with the oil supply is compressed into tiny bubbles at 100 PSI in the nozzle line. When the burner shuts down, there is no longer pressure on the nozzle line and the bubbles expand forcing some oil out of the nozzle. It's just like the first few starts after you change the nozzle except that the air in the nozzle line is replenished over time instead of being gradually eliminated.

    Assuming the tank is nearby and below the burner, another possibility is that the return line goes into the top of the tank but does not extend into the oil. Between cycles, the line can drip and the pump can get air in it through the return line. On startup, more air will be supplied to the nozzle line, continuing the effect described above. This will be more of a problem with the longer off cycles in warmer weather. In the winter, there will be less time for all of the oil to drip out between cycles.

    If either of these is the case, a vacuum test of the supply line and capping the return line and using a Tigerloop should fix the problem and reduce the environmental risk of getting a leak in the return line.

    Tom M.
  • MikeB34
    MikeB34 Member Posts: 155
    All Good

    All these suggestions are good. Change the nozzle would be the 1st thing. solenoid if you don't have 1. retention head burner if you dont have 1 (Beckett Af series comes with a solenoid).Then do a complete set up. overfire and chimney draft check. Smoke test the whole anchelada. Good luck
  • Doug Oest
    Doug Oest Member Posts: 34

    One more thing. I said in my last message that you have to insert the by-pass plug for a single pipe system- WRONG. It's been a while since I fooled with oil burners. I just checked the Suntec Pump manual. You insert the by-pass plug for two pipe systems and remove it for single pipe systems. So, if your gonna do that bucket test, take the by-pass plug out temporary, plug the return port and only use the inlet port. Then, when your done with the test, put it back the way it was for two pipe. Sorry for the confusion. I guess the thing here is if the problem still exists, you know it's in the pump and not in the fuel delivery system. Hope that makes sense!
  • geno_3
    geno_3 Member Posts: 2
    oil tank / air leak

    It may be time to replace the tank any way. Contaminating the soil is now very expensive and involves remediation, which means you dig until it's clean. There's no reason why you couldn't just take the lines off and put them in a bucket as they are. The pump will run and you'll know if that's the problem. If the system and tank are old you may have bad lines, fittings. I've dug up tanks and found some strange stuff. Call another company and see if they'll take a look for free, a second opinion might help solve your problem but if they agree with your present co. stick with them. BEWARE of Salesmen. If the tank is over 10 years you should think about replacing it anyway. These days selling a house is difficult with an in ground tank.
    Good Luck and let us know how you make out.
This discussion has been closed.