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Pressure held for 24 hours, then I removed gauge.

Suntec a2va-7116 says pressure will drop then hold when burner is shut off. "Cut off pressure could be less then 80%. The important operation is that it drops to some level and stops." "If pressure drops to zero the unit should be replaced."

So mine dropped from 100 to 63, then slowly continued to drop and was at 45 after 24 hours.

I asked Beckett and they said it should hold for 10 minutes.

Then they said that I should replace my pump. Ive asked twice and they wont explain why I should replace it.

Thoughts?

Thanks, Paul   

Paul Mars
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  • It depends on what holds the pressure. If the pump, then the seals are leaking. A solenoid tend the valve is leaking. The pump might be able to be rebuilt, but usually takes a few days without heat. – crip659 Jan 18 '24 at 20:45

1 Answers1

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Based on a previous question, you have a smoky flame, a gosh-awful mess in the firebox and the nozzle drips when not running. There is currently no fuel oil cutoff solenoid, as you said that the pump output goes directly to the nozzle. The pump produces 100 psi when running, which you say is within spec.

Replacing the pump may improve the situation. The dripping at the nozzle is probably due to the pump being worn and allowing fuel oil to seep through the space between the gear pump's "teeth" and the walls of the pump chamber. Since the fuel oil level in the tank is higher than the nozzle, there's a small head pressure and over time a significant amount of oil can get through.

It would be much less expensive than pump replacement to add an aftermarket electric solenoid fuel oil valve as a positive cutoff when the pump and blower are not running. This seems a reasonable alternative, since the pump is producing adequate pressure. If this is available, the only fuel that can dribble out after a flame cycle is a drop or two due to expansion as cold fuel oil in the nozzle assembly heats up by being in a hot firebox after the flame goes out.

If you have air in the fuel, you can actually get a little stream of oil after the flame goes out due to the air bubbles expanding as the pressure drops.

Air bubbles in the fuel oil can also cause an unstable, smoky flame. Air can be introduced by a loose or poorly made-up flare fitting in the fuel line on the suction side, an imperfect seal on the fuel filter housing, etc.

Can a worn pump introduce air? What if the shaft seal on the gear pump is worn? Could that pull air through the seal on the suction side and be the cause of all of the problems? It's possible, but I can't say how likely this scenario is.

If you could hook up clear tubing to the pump output and run the fuel oil into a container, you'd be able to see any bubbles. There shouldn't be any. If you do get bubbles and all connections are tight, you need a new pump. If you get no bubbles, I think your best approach is to add the electric valve.

FreeMan
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MTA
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  • No worries! That's what edits are for. ;) – FreeMan Jan 19 '24 at 14:33
  • The pump has internal shutoff which appears to be working properly. The pump is higher then the tank. The line goes up about 9' then across about 25, then down about 5' to pump. It is now running again with zero smoke. Although its like a 3 or 4 for the 1st few minutes. – Paul Mars Jan 19 '24 at 21:59
  • @PaulMars If it starts smoking again, you'll want to check for air bubbles on the high pressure side of the pump coming from a source on the low pressure side. Filter gasket? That's a long run of tubing, so any place where there's a joint is suspect. – MTA Jan 20 '24 at 02:24
  • Early in 2023, but after my jan smoke test I changed the filter housing. My 2a 700a started leaking and i replaced it with an F20 Westwood. So last night I decided to disassemble & reassemble that to make sure no leaks. Then I started to wonder if that housing being smaller is an issue. – Paul Mars Jan 23 '24 at 13:21
  • @PaulMars You can eliminate any guesswork about leaks by checking for bubbles on the high pressure side. Even if you can't find suitable clear tubing, you can just make a short length of copper tubing from the pump run into a coffee can. With the end of the tubing submerged in fuel oil, you should have fuel flow but no bubbles. Any bubbles at all suggest an air leak on the suction side or a seal failure in the pump. – MTA Jan 23 '24 at 17:25
  • So I still wouldn't know if it's pump or line leak. Why does this site take a carriage return as a post comment command? I guess it don't like paragraphs. The f20 filter is much smaller but it's still like 13 gph so i dont think but im not sure if that is an issue – Paul Mars Jan 23 '24 at 17:44
  • @PaulMars A 13 gph filter is plenty big. If you get no bubbles at all, line leaks and pump wear are eliminated as possible causes of air bubbles that cause a smoky flame. If you do get bubbles, you can turn off the valve at the tank and attach a Mityvac or another hand-operated vacuum pump+gauge combo at the end of the line at the pump. If you pump it down as far as it will go and it holds vacuum, the line is intact. Then it must be the fuel pump in that case. – MTA Jan 23 '24 at 19:34
  • Replaced oil filter fittings and tank fittings. Bleed the bubbles out as i always do. But then i remembered recently I saw on beckett site says bleed for 15 seconds with no bubbles. Ive never done that long. So, i tried that today. Every time i open the bleed valve it runs w\no bubbles for 13 seconds, then off & on bubbles. Never more then 4 sec w\o bubbles. – Paul Mars Feb 02 '24 at 21:27
  • Too long by 197 characters – Paul Mars Feb 02 '24 at 21:27
  • Continues like that until i close valve to empty my container (20-30 seconds). Then when open again it runs w\o bubbles for 13 seconds and repeats bubbles as above. Did that 7 times w\heater on the whole time (never cycled off). 7th time tried a larger container and after about 45 sec w\bleed open, heater cycled off.

    Smoke kept varying from 2 to 5 between each bleed. Why no air bubbles for 13 sec each time? Is this a bad pump?

     – Paul Mars Feb 02 '24 at 21:28
  • @PaulMars Replaced fittings does not mean leak free fittings. Either the pump or the line or the filter housing or the fittings are leaking air, and until you pump it down as described above, you don't know which. If you replace the pump and the bubbles stop, it was the pump. If you still get bubbles, it's the line or fittings or filter housing. If you get a Mityvac or another source of vacuum with a gauge you can test and diagnose instead of replacing parts on a hunch. I can't explain the 13-second bubble effect. – MTA Feb 03 '24 at 01:55
  • If Mityvac shows a leak, where is it? Which fitting, or maybe filter, or tank valve? – Paul Mars Feb 04 '24 at 11:16
  • @PaulMars It all depends on which part of the system you are connected to. If there are several components connected and all are possible candidates for a leak, disconnect components until the leak stops. The last component disconnected is the one that's leaking. And if everything before the pump shows no leaks on the first attempt, it's therefore the pump that's leaking. – MTA Feb 04 '24 at 12:39
  • My oil line has a leak and it is not at the tank\filter area. Some of this line might be as old as the house (1952).

    Im replacing the entire line. Do i need to use copper pipe?

    Can someone recommend one of those flaring tools for under 100$.

    What is the best filter to use? Im not sure I like this F25.

     – Paul Mars Feb 06 '24 at 19:55
  • @PaulMars You can check with your local building department to see what kind of tubing is allowed, but as far as I know almost everyone uses 3/8" soft copper tubing. This is also available as 3/8" copper with an orange polyethylene jacket, fuel rated, if copper corrosion is a problem in your area. Been using the same flaring tool for 30 years, so can't help you there. (A new question on this site to find a good flaring tool or fuel oil filter will be closed as an off-topic shopping question; sorry I'm not up on current flare tool or filter brands.) – MTA Feb 06 '24 at 20:23
  • Copper tubing labeled for refrigerant is the most economical. Some label it as M and I think that would be thick enough. – Paul Mars Feb 07 '24 at 12:14
  • @PaulMars Type M has the thinnest wall, lowest strength but lowest resistance to flow because of its larger bore. Yes, it is commonly used for fuel oil nation-wide, but the only way to know if it is allowed in your jurisdiction is to check with the local building department. Some locations require type L or better. I would use M if it's not prohibited. – MTA Feb 07 '24 at 14:09
  • Still aur with new tubing. I started bew thread titled – Paul Mars Feb 19 '24 at 21:10
  • What the f am i doing wrong, this site keeps posting befire im finished – Paul Mars Feb 19 '24 at 21:12
  • Still air in tubing. I replaced it all. I started new thread titled Air in oil line oil heater – Paul Mars Feb 19 '24 at 21:13
  • @PaulMars I embedded your image within your new question. Many won't go off-site to view an image. You can use the mountains icon to add an image to a post. – MTA Feb 19 '24 at 21:18