Intermittant air in oil furnace line


  #1  
Old 02-06-19, 08:08 AM
D
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Intermittant air in oil furnace line

Hi all, Hope someone can please help me. Beckett forced air gun furnace in mobile home. Will run fine for days, even weeks, then wont fire, find there is no fuel do to air in the line. I bleed it and its ok again for who knows how long, and its driving me nuts. New transformer, nozzle, and pump screen last year.
I don't dare go away in the winter for any length of time, because I don't know when it will act up again.
No visible leaks in the line going outside to tank. Its a one line system going down through the top of the tank couple inches off the bottom, and yes, tank is mostly full.
Praying someone else has experienced this and has been able to tell me what to do. Thank you
 
  #2  
Old 02-06-19, 12:16 PM
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D,
You are losing your prime which is no big news to you. The only way to lose your prime is through an air leak which breaks the vacuum and lets the oil run back into the tank. Oil delivery system needs vacuum to work. It's like filling a straw with water and covering the top with your finger which creates vacuum to hold the water in the straw. When you remove your finger, you break the vacuum and lose the water. That's what is happening to your oil so you must find the cause.

The air leak does not have to be big enough to leak oil but enough to break the vacuum and never see any oil dripping.

If you have an compression fittings change them to flair fittings. The ferrule in the compression fittings can cause leaks that are hard to detect. Another possibility is you pump gears might be worn.

Bottom line is you have an air leak from the tank to the pump somewhere. Check your oil filter and make sure everything is tight, check your filter gasket.

You can install a check valve or a tiger loop. A tiger loop would bleed the air from the line automatically but find the cause is best.

https://www.supplyhouse.com/sh/contr...il+de-aerators

Hope this helps a little.
 
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Old 02-07-19, 04:20 AM
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Spott, Thank you. So Its possible to have an air leak at the fitting yet not see oil? There is one splice, its flared. Also, where the line goes into the top of the tank, it goes through a compression fitting to secure it to the entry point. I saw where another person had an issue where as the fitting over time through vibration or whatever, caused a pinhole where he was losing prime.
And, its possible the pump could be bad, is that right? I see Amazon has a pump for like $80.00
Really appreciate the advice, thanks again. D
 
  #4  
Old 02-07-19, 07:30 AM
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Chasing such a small & intermittent leak will drive you absolutely crazy.
Check valves should never be installed in a single line system due to the potential of over pressurizing the line in hot weather & blowing the pump shaft seal.
The idea of a Tigerloop is great if there is room outside of the furnace cabinet which in a mobile home isn't too likely.
 
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Old 02-07-19, 11:29 AM
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Thanks Grady. But no check valve or outside filter in the line, just have the line 2-3 inches from the bottom of the tank. Run straight kero. so its not like dirty fuel oil.
 
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Old 02-08-19, 10:57 AM
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There's always the option of running a return line. I don't like 2 line systems but with straight kero, it pretty much eliminates the sludge problem. If you do opt to do the return line, run it into the tank at or near the same depth as the suction line.
 
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Old 02-09-19, 06:34 AM
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Thanks. Think Im going to call the man and see if he can check out my pump, as it sounds like that could be a possible cause?
 
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Old 02-09-19, 10:56 AM
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It could be the pump but not real likely.
 
 

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