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Problem with Oil Fired swimming pool heater

Bob Chapman
Bob Chapman Member Posts: 11
We have an unusual oil fired swimming pool installation.  550g oil tank is buried on side of house, new single oil line was buried and run 200' to new pool heater and up a hill next to pool.  Vertical height above tank is at least 24'. Contractor put Sundstrand B pump on Beckett Burner and Sid Harvey oil de-aerator. When mechanic uses push pull pump and burner starts, we read 17" vacuum on filter. When pool heater shuts down, we have a check valve at the base of the pool heater, but none at 40yr old buried oil tank. So now the oil drains back down to the tank and on next call for heated water, oil pump goes out on lock out.

     Oil company only has 150' hose so relocating tank, even if homeowner lets him- is not an option.   Originally Teledyne pool heater was no problem until 2 years ago which was the same time NYS started using ultra-low sulfur oil.  New unit is ThermoDynamics OTF1600 2.5gph firing rate.

Does anyone have any suggestions?


  • Bob Chapman
    Bob Chapman Member Posts: 11
    my bad

    bc contractor says I was wrong on vertical height only 12-14 feet
  • icesailor
    icesailor Member Posts: 7,265
    The Big Lift:

    It worked before, and it doesn't after it was changed? What changed?

    You have a suction leak on the oil piping at the new connections. "Sid Harvey Oil De-aerator"? Is that a "Tigerloop? If not, install one. Oil codes require ALL flare connections and no compression fittings. Did the installers use thread seal compound like Gasoila or Rectorseal #5 on the flare union faces or are they straight copper to brass bare ground joints? They can leak is so. Use paste on the union faces.


    If the vacuum leaks don't stop, properly applied QUALITY Teflon pipe tape  (like Blue Monster) CORRECTLY applied to the male threaded joints with Pipe Dope applied to the threads both male and female will stop any stray vacuum leaks. That means no more than 3 wraps and none over the end of the threads!!!.

    Where is the filter and what kind is it? Is it a Spin-On like a Garber (owned by General Filter) with a vacuum gauge on it?

    As a rule, the oil left in a Tigerloop is more than enough to fire off a vacuum leaking pump and line until the Tigerloop can build enough suction to overcome the vacuum leak, vent the air and then fire off the burner.

    Where does the person put his "Push-Pull" Pump? If the fuel filter is connected to the inlet of a Tigerloop and the restriction gauge is also installed on the filter, it should show the suction/vacuum lift (Vacuum when pumping including the vacuum head needed to overcome the restriction) and when it stops, the actual static suction/vacuum lift (lift when not being pumped. Note what the vacuum lift is 1o seconds after the pump stops. Note the suction pressure. It shouldn't drop at all. Especially if it is off for any long period of time.

    Pump shaft seals are sensitive, they can leak. If you use a Tigerloop, the pump by-pass plug must be installed and it becomes a two pipe oil system that develops far more suction pressure than the same pump connected as a single line pump.

    If it worked before, what changed? What has been done differently.

    Around a pool? Landscaping? Irrigation? Are you sure that no one (who are all like little children in denial, (I didn't do it). No one hit the copper root with the shovel when planting the new shrub.
  • icesailor
    icesailor Member Posts: 7,265
    Oil De-aerator:

    Is this what you have?


    That's a re-branded "Tigerloop".

    Is the By-Pass plug installed in the pump?
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,541
    200' horizontal and 12' vertical?

    Way too much lift,I would go with a pressurized system. http://www.suntecpumps.com/PDFs/Installation%20and%20Service%20Manual.pdf

    As a band aid,you could increase the prepurge time to the max on the Genisys,45 seconds. That may buy enough time to reprime the deaerator before the TFI. If that doesn't do it,wire around the primary and see how much time you need to prime. If it less than 120 seconds, a Carlin Promaxx has 120 second prepurge.
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • icesailor
    icesailor Member Posts: 7,265

    Is it the 12' lift or the 200' of oil line that is the problem?

    The pool was existing as I understand it? The tank was existing? Or is it a new tank?

    Its my understanding that the oil line is what is new. Even if the new oil line is too small, it won't loose its prime. It will show a correct vacuum pressure for when it is at reat. It will have excessively high vacuum when running. As soon as the pump stops, the vacuum will drop to the correct vacuum. If you are getting foaming in the top of the Tigerloop, when the pump/burner starts, the prime was lost. If you are getting the slightest amount of foaming in the Tigerloop when it is running, there's a problem.

    You KNOW that if the 200' oil line is too big, the oil will release gas and it will act like air bubbles and collect on top of the pipe. It shouldn't be larger than 1/2" OD, 5/8" at the largest. How many GPH is this burner fired at? Is this oil line in a sleeve? It should be. If it is leaking into the ground as a weeping copper root, the owner isn't wealthy enough to do the EPA required cleanup. If said buried oil line was in Massachusetts, they'd be digging it up and sleeving it.

    Unless someone special ordered a 200' length of copper tube, there are joints. Are they flared? Were the union faces lubricated?  Was a double tapped bushing used at the tank with a continuous sleeve or is it 2- adapters with flare nuts? Were the union faces lubricated? Was the flaring tool one of those cheap Smoosh the tubing down with the plunger type flaring tool or the much more ratchet type that the plunger rolls around and rolls out the flare for a perfect flare every time regardless whether you ream the tube first or not?

    Did UPI personally do the installation or are you asking because no one can figure out why this problem is occurring?

    Are you VERY sure that no one has been gigging around and hit the copper root? What size is the pipe?

    You need a vacuum gauge at the inlet of the filter, before the Tigerloop, where you can isolate the line and see if the vacuum drops. You wouldn't do a service call on an electrical problem without a "Wiggy" or a Multi-tester, you shouldn't be doing Oil Burner troubleshooting without a Vacuum Gauge.

    To prove my points, take a 5 gallon container of fuel oil and connect the burner to the container. Leave the system off fore the same amount of time that you do when the problem occurs. Turn on the burner. If it fires right up and runs until the container is empty, you have a suction leak.
  • icesailor
    icesailor Member Posts: 7,265
    Suntec Manual/PDF


    That must be a new manual that Suntec put out after Danfoss bought them out. All that new stuff certainly wasn't in my older Suntec Manuals. Stuff like waste oil pumps.

    There needs to be more history on this. If it worked before, and nothing was moved, but just changed where is, what else has changed? If it is old, they didn't have Tigerloops. Someone has been playing trial and mechanic on this problem. Suntec doesn't want you to go more than 100' on a suction line and 5/8 OD is the maximum. Reading between the lines, it is the vacuum/suction pressure that is the deciding factor. Good part about oversized lines.

    But I always get back to "If it worked before, why doesn't it work now? What changed?

  • icesailor
    icesailor Member Posts: 7,265
    Full of Gas/Check Valves:

    The system can be as tight as a crabs @$$ and that's watertight. According to someone I once worked with. But oil will "Outgas" and create gas bubbles. They act and appear just like air.

    Check Valves in an oil system just mask the symptoms of a bigger problem and create their own set of problems. Far worse than the problem they are supposed to solve. #1 being that they had large amounts of vacuum pressure to the system in the form of restriction. Which then add to outgassing. That appears to be a vacuum leak when it actually isn't.
  • billtwocase
    billtwocase Member Posts: 2,385

    If there is actually 17" vacuum, I would say you don't have an air leak. More or a line that is kinked, plugged, or undersized. How far down is this tank? 12 feet lift, unless the boiler is above ground level, don't seem right. That is a long run, but the lift is actually more of a culprit in most cases. installing the 2 stage pump won't help here. Was the pump a clean-cut, or does it have a solenoid? I agree with Rob on a long pre-purge. Sounds like the tank settled, and the line underground pinched