Fuel oil furnace won't pull fuel through line.

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Old 02-04-19, 02:58 PM
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Fuel oil furnace won't pull fuel through line.

I have a two line Beckett fuel oil furnace. It has been out for over a week after it had a minor puffback. I cleaned the whole system of soot, vacuumed everything out and inspected it all for damage, there was none but I decided it would be best to replace the components anyway. I Just finished replacing pretty much everything in the whole system, blew out the lines to remove any sludge and upon putting it all back together i find that there isn't any fuel coming from the line. I have isolated the problem to the main fuel line because I can force air in to pressurise the tank but I can't suck any fuel out. my question is, what would cause this? And before you ask it isn't the pump, I am using alternate means to apply pressure and vacuum to the line. Thank you in advance for any help you can provide.
 
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Old 02-04-19, 03:00 PM
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What is the suction reading the pump pills while running?
What parts did you replace?
Is the pump strainer clean? Can you prime the system via the bleeder port?
 
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Old 02-04-19, 03:11 PM
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It's rated to 140psi. Pump is new, electrodes, ignitor, nozzle, and filters as well. Everything on that end is good. I have the main fuel line disconnected and have blown pressurised air back to the tank and i can hear bubbles. I know the tank is holding pressure because when i open the return line ( which is also currently disconnected) then air comes out, but if I open the main line there's nothing, even though that is the line I pushed air in. I have even tried pushing air through the return to the tank with the main opened and still nothing comes out. I'm stumped as to what would cause this.
 
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Old 02-04-19, 03:28 PM
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Usually when you can't suck fuel out or a suction won't start.... you have a leak.
Do you have any compression fittings in the suction line ?
 
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Old 02-04-19, 03:37 PM
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Your tank should NOT hold pressure. The tank must be vented to the atmosphere.

How are you pulling a vacuum on the suction line other than with the fuel pump?
 
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Old 02-04-19, 03:40 PM
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I have inspected the whole length for leaks and there are no compression fittings and I can't hear any air coming out of the line when it's under pressure. Is there anything else that would cause air to still go up that line and pressurise the tank without fuel coming back out?
 
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Old 02-04-19, 03:43 PM
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Do you have a vacuum gauge?
 
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Old 02-04-19, 03:45 PM
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The tank is only holding pressure because I have everything capped off right now so I could test for leaks. The tank was vented when i blew out the lines. I am currently using compressed air at low pressure.
 
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Old 02-04-19, 03:51 PM
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I do not have a vacuum gauge. I had a pressure gauge connected to the return temporarily to make sure the tank was holding pressure but that's it.
 
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Old 02-04-19, 04:58 PM
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Just a thought from reading your post. You said blowing air through you supply to the tank you can hear bubbles.

What is your oil level and how far from the bottom is your supply line. Your tank may show oil but too low to pull.

You can try getting a separate container of oil or kerosene and run a temp line to see if all your components are working or try filling your tank. Your supply line if coming from the top is usually about 6" from the bottom so you don't pick up sludge. The downside to that is that leaves quite a bit of unused oil before you need oil.
 
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Old 02-04-19, 05:28 PM
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The tank is in ground so I'm not sure where it draws from but there's about 16 inches of fuel in the tank, I'm pretty sure it's a 500 gal tank.
 
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Old 02-04-19, 05:40 PM
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Without knowing how far down from the bottom your supply line is you're flying blind. You should have a straight shot to the bottom where you stick your tank to put a temp line down to a couple inches from the bottom where you know there is oil and see if you can pump oil from there. If so your oil might be just too for your supply line.

You said you changed the pump. Did you put the bypass plug in the new pump for 2 pipe systems.
 
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Old 02-04-19, 05:47 PM
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Yes, I installed the bypass plug in the return port. And I've been able to run at as low as around 5 inches left in the tank. Is it possible that part of the line in the tank has failed? I just can't figure out why I can push air through both lines to the tank just fine but not get any fuel out anything back when I put a vacuum pump to it. Shouldn't I at least get air?
 
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Old 02-04-19, 05:53 PM
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It is possible something has happened to the supply. If you run a temp line and see if you can get oil that would narrow it down I would think.
 
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Old 02-04-19, 05:59 PM
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I mean I'm pretty sure i have it narrowed to the supply already, I'm just trying to figure out why I can push air through the supply to the tank and hear bubbles but not be able to suck anything out. Even using a separate vacuum pump that is not part of the furnace, nothing comes out like it's clogged.
 
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Old 02-04-19, 06:05 PM
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Is it a copper line or steel line inside the tank for your supply. If your line is in the oil and hooked up to some kind of transfer pump it has to come up. If not and the temp line does it's the line but why, who knows. Has it ever happened before.
 
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Old 02-04-19, 06:11 PM
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You will never get any oil from the return because they usually just put that a few inches into the tank. I understand you're saying your supply is clear with air being able to go through so that just means it's not in contact or enough contact with the oil for some reason. Not much you can do except run another line or dig up the tank.
 
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Old 02-04-19, 06:13 PM
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It has never happened before to my knowledge but it's an old system that has been in 45+ years. So if it is the line then what are my options for repair? I apologise for all the questions, I am no furnace repair man by any means but I am mechanically inclined and have to make due because there aren't any technicians for 100 miles. I have torn everything apart and replaced all the components and aligned everything to spec. Now I'm just stuck because i can't get fuel from the tank.
 
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Old 02-04-19, 06:17 PM
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I wwasn' trying to pull from the return, I eventually had capped off the whole system because it wasn't drawing and tried to push air in the return while the supply was open ( disconnected and over a bucket), all that did was build pressure in the tank and nothing came out the supply. The same if I shut off the return and push air into the supply, the tank became pressurised and still nothing came back out the supply, not even air.
 
  #20  
Old 02-04-19, 06:27 PM
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Not a lot of options except to pump the oil out and into a temporary barrel and run a new line from that to the burner or use pipe that you use to stick your tank and install another line and connect it to your burner. You can install an indoor tank. Don't know what your situation is.

What we used to do is get a pipe or anything rigid and tie a garden hose to it and put it in the tank and attach it to a transfer pump to remove the oil when changing tanks. If there's oil in there you just need a hose and pump and a container to put it in. Just a lot of transferring until warm weather comes.

Don't know if it would help but are pics possible. If you could get some oil inside you only need 1 line to the burner.
 
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Old 02-05-19, 05:26 AM
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Hi, you might have plugged a foot valve in your suction. I have done it before on a bigger tank. That's why after only used a push pull pump.
 
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Old 02-05-19, 05:57 AM
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I’m not one of the experts here – and that’s for sure. So this might be out in left field. But is it possible there is some kind of blockage in the tank at the entrance to the supply pipe. Like maybe some kind of sludge-ball or something like that.

When you force air in the supply line towards the tank, the sludge-ball is dislodged and air makes it into the tank and you hear bubbling. But as soon as the air flow stops the sludge-ball drops back into place blocking the supply line again. Action is almost something like a check valve.

Hence sucking oil from the tank towards the burner can’t happen.

Just a thought.

Well I should have read guyold's previous post more closely. Guess the foot valve addresses all of that.
 
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Old 02-05-19, 08:25 AM
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Squidbillysean's story rang some bells.

I have in ground 560 gallon tank. Bottom 45 gallons, below 14.5" can not be used.
Years ago sucked oil out of line until fuel flow ended. Then measured level to find start of usable gallons of oil.

Profile of oil line from tank to burner is "U" shaped. Every few years it acts like a trap and develops blockage. Blow it out with compressed air.

Have shut off valve in tank line before filter with tee for air fitting. Did not want 100 psi on filter or pump.

Put vacuum gage on filter out to monitor filter status. After changing filters, if vacuum is still high, time to blow out line.
 

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  #24  
Old 02-05-19, 10:02 AM
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That actually sounds pretty close. I've normally been able to go down to 5 or 6 inches of fuel before it stopped pulling ( there'st about 16 inches in now).how much vacuum is usually required to pull fuel from the tank?
 
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Old 02-05-19, 10:39 AM
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My 2 line system has about 30 feet of 3/8 copper.

With clean filters is about 2 psi vacuum. At 12 psi change filters.

Since your are drawing from near bottom of tank would suggest sludge removal as outlined in my post #14 below. Every time you get fill it stirs up that sludge.

https://www.doityourself.com/forum/b...oil-tank.html?
 
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Old 02-06-19, 07:59 AM
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If you can hear bubbles when blowing back thru the return line, that says the return goes down into the oil. If that's the case, try switching supply & return lines. There could be a pin hole in the suction which won't allow you to pull a vacuum but not large enough to allow all the air to escape when being pressurized.
 
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Old 02-06-19, 11:43 AM
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Grady,
He said he heard air bubbles from the supply only. When he put air to the return he said no air came back from the supply as it did from the return which would tell me that the supply is most likely in the oil but to your point about the pin hole which is a possibility, could be a definite cause which could be proven with an oil delivery to get the pin hole into the oil unless it's at the very top.

If the pin hole is above the oil it could prevent the vacuum which would explain the problem but if the oil was at a higher level where the pin hole would be in the oil then the pin hole would be a moot point because that would eliminate the vacuum problem and he should be able to pull oil.
 
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Old 02-07-19, 06:55 AM
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A vac gauge would be a huge help in trying to figure out his problem.
 
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Old 02-09-19, 07:00 PM
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Vacuum leaks are often hard to locate. Carefully blowing line with compressed air might expose leak. It could also cause mess.
 
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