No prime on fuel pump

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  #1  
Old 10-19-18, 06:43 PM
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No prime on fuel pump

Ran out of fuel on my boiler with a beckett burner that has a danfoss bfph unit 071n1151. Always primed ok in the past. Replaced unit with a A2VA-7116. Same problem. Blew out line about 35' back to 500 gallon buried tank outside. Hooked up an 12 volt electric fuel pump and got great flow. Put line back on at filter, opened the small screw on outlet of filter and had gravity flow at that point. Filter to pump pipe is 5". Still would not prime. Checked to see if shaft was turning, it was.
Stumped!
 
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  #2  
Old 10-20-18, 03:16 AM
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Check the Screen in the Pump . . . . it's typically clogged up when you've sucked the debris and paraffin up from the bottom of the Tank. Often, the gun Tube down to the Nozzle is also clogged.

How long has the same Nozzle been in there ?

Here's one of those Strainer/Screens for the Suntec A2VA-7116 so you know what they look like.

https://www.ebay.com/itm/SSC-109-3715101-RS939-A2VA-7116-A2EA-6520-A1VA-7112-A-pump-screen/331881940623?epid=1200219522&hash=item4d45b4868f:g:rW0AAOxytdlQ~4bd:rk:2f:0

The screen can be cleaned with an old toothbrush. You may find that the tube down stream to the Nozzle is also clogged, along with the Nozzle. This Screen is often neglected even by the "Professionals" around here (they'll often opt to change out the entire pump).

October is a good time to have this problem.
 
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Old 10-20-18, 03:45 AM
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If you have an underground oil storage tank as you stated, you should have a 2 pipe oil supply, 1 pipe for supply and 1 pipe for return oil back to the tank. If that is the case, did you follow the instructions that should have come with the pump and install the "bypass plug" as the directions would have stated. The bypass plug is usually in a small plastic bag shipped in the box with the pump. If not, you will not get the pump to prime. Also, opening the small screw on the oil filter will not give you gravity flow on a buried oil tank.If you have a single pipe oil supply disregard the previous statements.
 
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Old 10-20-18, 03:34 PM
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It has a one line system. It has worked fine for 42 years. Before putting the new pump on checked and cleaned the screen in danfos pump, clean.
the extension drive tube seemed to be turning, but maybe slippiny on the pump shaft? Doesn't seem possible it would do that.
Earlier today before I had to leave, I pulled the plug out on top where you would put a pressure gauge and fuel ran out of that on it's own. I thought the drive tube fits in only one position?
dirt and sludge would have to get by the wool filter. The old filter and nozzle were about 7-8 months old.
is there a metal clip suppose to be on that drive tube?
will loosen joint on exit port that enters into burner to see if there is any pressure. On the old one I did until it used up the fuel and lost prime.
 
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Old 10-20-18, 04:52 PM
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It has a one line system. It has worked fine for 42 years. Before putting the new pump on checked and cleaned the screen in danfos pump, clean.
the extension drive tube seemed to be turning, but maybe slippiny on the pump shaft? Doesn't seem possible it would do that.
Earlier today before I had to leave, I pulled the plug out on top where you would put a pressure gauge and fuel ran out of that on it's own. I thought the drive tube fits in only one position?
dirt and sludge would have to get by the wool filter. The old filter and nozzle were about 7-8 months old.
is there a metal clip suppose to be on that drive tube?
will loosen joint on exit port that enters into burner to see if there is any pressure. On the old one I did until it used up the fuel and lost prime.
 
  #6  
Old 10-20-18, 07:26 PM
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D,
With the limited info just a couple thoughts. Pics would be good of the pump and coupling at least.

It doesn't sound like it's the pump and by changing it out you seem to have proven that.

Have you checked the coupling between the motor and the pump. That coupling is what operates the pump when the motor is powered.

If that coupling is loose or defective and cannot turn the pump shaft you will not get any oil.

When you had oil at the pump when you pulled the plug that is telling me it's getting there from the tank so the line must be clear. Because the pump shaft is not turning it does not create any pressure to be delivered to the nozzle.

I would check your coupling before changing any other parts. Although your nozzle could be plugged or need changing that is a moot point at this time when you can't even bleed your pump.

First things first, also make sure all your fittings are tight so as not to break the vacuum in the line between the tank and the pump.

Hope this helps.
 
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Old 10-20-18, 08:17 PM
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Will remove unit and hook up to an electric drill and check plasti drive shaft.
 
  #8  
Old 10-20-18, 08:20 PM
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There are different size ends on that coupling to accommodate different size shafts.

If you lift up your transformer you can spin the fan with your hand and check to see the condition.
 
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Old 10-20-18, 09:11 PM
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The plastic drive was spinning when I reset as seen through air adjustmen, but could not see if it was turning the shaft or not. Pulling unit off and hooking it to the drill will confirm the unit making pressure and inspect the drive.
 
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Old 10-21-18, 07:18 AM
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You could also get a gallon or two of diesel fuel at the gas station and then take a small plastic tube and connect it to the input port on your fuel pump. Take the other end of the tube and put it in the fuel container. If your pump runs and your burner runs then the problem is with your fuel line somewhere. Maybe like a vacuum break as spott suggests.

If the pump still does not prime you know the problem is definitely at the pump – somehow.
 
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Old 10-21-18, 07:28 AM
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Already tried drawing fuel but wouldn't. I have fuel in the pump, that leads me to believe it is not turning.
 
  #12  
Old 10-21-18, 07:37 AM
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I see what you are saying. Then it seems like the problem must be at the pump. I just changed my fuel pump about 2 weeks ago, same as yours: danfoss bfph 071n1151. But I replaced with the identical unit.

It seems to me, and I might be out in left field, but I don'e see how you could get things back together if the coupling wasn't properly on the pump shaft and motor shaft. It just seems to me no way could you tighten things up.

Could it be just a defective pump? Too bad you don't have a pressure/vacuum gauge.

Well just thought more. Is there a way to get it all together without the coupling connected properly? It doesn't seems so. But maybe if the coupling got pushed down the motor shaft too far the pump shaft would not be connected to anything. I don't know if that's possible - my mechanical visualizing skills stink!!
 
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Old 10-21-18, 08:56 AM
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I well understand that the fuel line from the Tank to the Pump has been thoroughly cleared; but I'm still not so confident that the fuel line from the Pump down the gun tube to the Nozzle has been deemed innocent.

Because the OP says he changed the Nozzle recently, I will assume that the Tube was cleaned at that time, so I won't mention it again.
 
  #14  
Old 10-21-18, 10:25 AM
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But would a blockage there stop the pump from priming?
 
  #15  
Old 10-21-18, 11:00 AM
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Originally Posted by ZoesDad
". . . But would a blockage there stop the pump from priming? . . ."
I'm not Clark Kent . . . . but I suspect that a blockage there would inhibit the Pump from being able to complete the priming process and vacate the Tube of Air and Sludge out through the Nozzle (which won't happen) so that clean Fuel Oil can enter.

But I don't know.
 
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Old 10-21-18, 11:10 AM
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A nozzle or tube blockage, although possible, would in no way prevent oil coming from the pump when bleeding because when that bleeder is opened up it does not allow oil to flow to the nozzle.

He must first figure out what the bleeding problem is the deal with the firing of the boiler.

Just my thoughts.
 
  #17  
Old 10-21-18, 02:48 PM
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I bet your first thoughts about the coupling are on target. Hope we find out - and the problem gets resolved of course.
 
  #18  
Old 10-21-18, 03:15 PM
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I'm don't think I'm confusing "bleeding" the Oil Line as being the same thing as "priming" the Pump in preparation for firing it up. The OP labeled the Thread as No Prime on Fuel Pump only after he had successfully bled the Oil Line from the Tank, so I never thought he was having a problem bleeding.

In my mind, the Pump may be nicely filled with Fuel Oil and all ready to go . . . . but it has no place to go because it can't first displace whatever is inside the Gun Tube.

I think that was my first experience with a clogged screen which had ruptured and allowed a build up of crud beyond the Pump inside the Gun Tube.

I took so much crud out of that Tube, it was simply amazing that the Becket Burner had tolerated it and kept on functioning right up until the Nozzle itself closed up shop . . . . What a Trooper !

And all because the Suntec Screen had been neglected for over 15 years !

But, maybe I'm the only one who ever had crud the consistency of toothpaste inside my Gun Tube ?
 
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Old 10-21-18, 03:39 PM
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V,
Bleeding and priming the pump are the same thing just different terminology. I'm just use to saying "bleeding" but it means the same thing.

I have never seen a tube as you described but no doubt they exist but in this case the tube being downstream from the pump and does not come into play until the pump is primed and removed of air it is a moot point.

The air trapped in the pump if that's what it is, prevents the oil from getting to the tube and nozzle so even if the tube were plugged, at this point it wouldn't make a difference.

Personally, I leaning towards a defective coupling but it wouldn't be the first time I was wrong.

GO SOX!!!
 
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Old 10-21-18, 07:06 PM
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Opening the line to the nozzle has no pressured fuel coming out.
The pups are interchangeable a d both have been used on beckett burners.
know more tomorrow after I remove unit from burner. There is no way dirt or sludge are going to get through a filter.
 
  #21  
Old 10-22-18, 04:56 AM
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Originally Posted by Duroc
". . . There is no way dirt or sludge are going to get through a filter . . ."
If logic were to always prevail, I would have to agree . . . . and maybe climate has something to do with it; but here's another explanation I can draw from my own experience:

Back in the 1980s, when I bought this Farm, the prior Owners didn't know that there would be a Fuel Adjustment at Closing, so they chose to run the oil tank dry, and we moved in in April to a cold house with no oil . . . . just an empty Oil Tank.

The Old Timer who delivered oil stayed around to prime the Burner (the predecessor to my current Becket AGF) and get us re-started; but the system had sat in a well chilled basement for multiple days (or maybe even weeks) . He explained that the paraffin suspended in the fuel oil had coagulated in the Nozzle Tube and turned into wax. We don't have the benefit of such skilled Oil Deliverymen (who are also Owners) anymore.

To get us going, I watched him disassemble the Burner and clean the blocked Nozzle Tube. He did not have to clean or change the Screen/Strainer at that time . . . . I don't even know if that old Burner's Oil Pump had a replaceable screen. I replaced it in the early 1990s.

Maybe this belongs in Ripley's "Believe it or Not"; but strange things happen when we run out of fuel . . . . maybe more so here in Vermont than in warmer places; but that suspended paraffin is always present in Number 2 Heating Oil; and under the right conditions, the congealed wax will adhere to microscopic particles brought in from the bottom of the Oil Tank.

Call me paranoid, but these experiences have led me to never letting my Oil Tank fall below Ľ Full, and tolerating the inefficiencies of my tankless DHW Coil by requiring my Burner to fire up throughout the Summer (which also serves to minimize condensation) so that the paraffin never cools down so much as to start coagulating.

So that's how some things like the paraffin can sometimes come from the refinery still in suspense and make it through all of our fancy filters and screens and then still chill and harden into wax before they get down to the Nozzle.

The coldest winters we've had here have reached -48°F, and I prefer to not have heating problems at that time, when I usually have more pressing things to keep me awake at night. But that's my story; serious problems often start when we run out of Oil.
 
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Old 10-22-18, 01:42 PM
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I was only out of fuel for less than 24 hours.
 
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Old 10-22-18, 01:45 PM
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Many times I've seen the pump end of the coupling stripped. With the pump not bleeding/priming, my money's on a bad coupling.
 
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Old 10-22-18, 03:32 PM
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Removed pump. Pump shaft has stripped out on coupling and turning on shaft. Motor end cap looks ok. The cap on pump end outside spline looks ok, but will get the whole coupling.
 
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