Leaking black iron oil tank fill pipe


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Old 03-06-21, 11:05 AM
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Leaking black iron oil tank fill pipe

Good Afternoon,

My oil-fired heating system is supplied by two 330- gallon tanks piped together, each with its own fill. One of the fill-pipe joints on a horizontal run leaks slightly--nuisance amount. It drips onto a paper towel draped on the tank, under the leak, such that if the paper towel is not changed every few months, the side of the tank will get a sheen on it, which I wipe down every few months, leaving that area of the tank looking shiny and new.

Are there any sealants that might fix it? I don't really want to pull all the pipes apart, although I suppose putting a cup of sorts under the leak might do.

Thanks.





 
  #2  
Old 03-06-21, 12:07 PM
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With that piping configuration, it would be a real pain to take pipes apart. Trying to seal threads already put together is nearly a wasted effort. The only thing I know of that MIGHT work is J B Weld but the joint would have to be absolutely clean & dry.
I would use a can with some oil dry in it then hang the can with a wire handle under the elbow.
 
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Old 03-06-21, 02:31 PM
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Thanks Grady.

I kind of thought I might try what you suggest, but am concerned that a good cleaning with something like brake-cleaner might make the leak worse if whatever I use to attempt a seal doesn't work. I guess the can and wire idea is the next best thing for now.
 
  #4  
Old 03-06-21, 05:27 PM
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KOTs joint likely leaks only during fuel oil fill. At most times in that spot there is no oil, pressure or leak.

A simple, quick fix would be to coat joint with high quality sealant, then wrap area with gasket material and use worm gear hose clamp around it.

Would not use ordinary pipe thread sealants. Here is one that should work:

https://www.supplyhouse.com/Supco-HS...h-Top-Jar-4-oz
 
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Old 03-06-21, 05:53 PM
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I would not worry if that was all it leaked as long as the fill pipes slope uphill all the way to the outside fill. If you do decide to take it apart to repair leak I would pipe it properly.
 
  #6  
Old 03-06-21, 09:15 PM
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Which ever way that pipe slopes, oil will drain into one tank or the other. Fill is usually not to top of tanks.

Since the only pressure is during delivery there appears to be little problem.

Quick fix may be over kill but that is KOTs call.
 
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Old 03-07-21, 04:00 AM
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I think I'll try some of the suggested Leak Lock, but not wrap it. I'd rather be able to keep an eye on what it's doing, so a can and wire seems to be the thing. And who knows--I might get lucky with it.

Four-plus years here, and I'm finally giving it a little attention.

Thanks folks.

KoT
 
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Old 03-07-21, 10:27 AM
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Leak Lock is a pipe joint compound. In order for it to work the pipes have to be taken apart. If I were going to go to that troube, I would use Permatex pipe joint compound or #2 Permatex. I've used these products for over thirty years & have found nothing which works as well for pipes in a fuel oil system.
You likely have a little puddle of oil sitting in that 90* elbow & slowly weeping out. Rbeck's mention of slope is spot on. Forty five degree turns instead of the 90* ells are far less subject to leakage since there is a constant slope.
 
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Old 03-07-21, 06:32 PM
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Many ordinary pipe thread sealants have issues with fuel oil so recommended Leak Lock which does not. For exsisting pipe connections, with zero or low pressure, it can be coated on outside of joint to seal.

DH as many sealants, including 3 kinds of Permatex. To simplify things recommended most approriate for KOT's issue.

Leak Lock is a state-of-the-art high strength, pipe joint sealant consisting of chemically resistant film formers, plasticizers, reinforcing fillers and solvents, useable on all clean metal or plastic surfaces.
 
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Old 03-19-21, 10:14 PM
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Isn't that the vent line? Why is there diesel in it?

A bead of RTV around the joint would likely fix the leak.
 
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Old 03-20-21, 06:03 AM
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Hard to tell if it is the vent or the fill to the left tank.
 
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Old 03-20-21, 12:29 PM
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SB,
You are absolutely right. According to the pics that pipe is connected to the vent/gauge fitting. The question I would ask also id why is there oil in that line at all.

If you were to take that union apart and remove the pipe from the tank you would see a round disc which is connected to a metal tube which is your whistle. That tube lets the air out of the tank as the oil is being pump in which makes the whistle sound the delivery person hears and lets him know when the tank is full.. When the whistle stops the oil has reached the tube and the tank is full.

There is no way that oil should be in that line unless vents are not working and the tank is getting over filled and leaks from that joint until the oil drops below that point. I would worry more about how the oil got there than the leak itself.

Below is a pic of what you have. There are more variations but this is an example. I'll post both so you can see what is available. There are different sizes for different sizes for different tanks.

https://www.supplyhouse.com/Beckett-...auge-36-Length

https://www.supplyhouse.com/sh/contr...%2Falarm+gauge

Hope this helps a little.
 
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Old 03-21-21, 05:38 AM
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Maybe the tank was over filled. Happens sometimes.
 
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Old 03-22-21, 02:34 PM
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The red block with the guage us a combo overfill preventer and vent.

There's a a disc and it causes the air exiting the tank to make a whistling noise when being filled. When the diesel gets to the disc, it stops whistling, letting the guy filling know it's full. Usually gives around 10% head room to allow for expansion with plenty of safety factor.

If the vent is leaking fuel, the tank is massively overfilled or they are filling from the wrong pipe.

May be worth having a plumber look at it to see what's going on. Something isn't right.
 
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Old 03-23-21, 07:09 AM
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Sumb.. When the diesel gets to the disc, it stops whistling, letting the guy filling know it's ful
Great theory. but if fill guy does not hear sound or is distracted bad things happen.

DH lives on road with a lot of traffic noise. Sound at best is hard to hear. Check outside vent cap regularly to make sure is clear.
 
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Old 03-23-21, 06:00 PM
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The oil in the line is probably due to improper piping and the way the oil flows new full. The proper way to pipe two tanks is fill one tank, use a crossover pipe between the two tanks and vent the second tank. All this should be done in 2" black iron pipe. Slope the fill and vent pipe uphill all the wat to outside termination.
Any pipe dope OK for petroleum products is OK to use. More often it is not the pipe dope that fails as it is the fittings. Use good quality fittings, not cheap imports. The taper is not consistently within spec as a good Ward fitting for example..
 
 

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