Sucking air

Big Ed

I agree get rid of the old oil lines. New unit , new lines is good practice...... The old ones seem to be plugged if your running 7" vacuum on one pipe..... 90 year old house ? Iron pipe for ol lines comming out of the wall ? Could be a plugged foot valve......Put a new tank in the basement...

Big Johnson_2

Sucking Air

I've just installed a new oil furnace and it seems I'm sucking air somewhere before the burner pump. I've installed a Tigerloop and I'm getting a solid 7 inches of vacuum. However, the oil in the tigerloop is very foamy and the burner thuds and chugs from the fuel loss. I've gone through all of my flare fittings and pipe connections.
Is there a way to find the leak? I thought of wrapping electrical tape around each fitting one by one and see if that takes care of it by process of elimination. I have no means of pressurizing the system without digging up my tank.

Thanks

EBEBRATT-Ed

This is a tough one. There really isn't any practicle way to leak test this without disconnecting and pressure testing.

You mention digging up the oil tank. Did you install new oil lines?? I would suggest repiping the underground section witn new tubing. By using double tapped fittings with "slide through" compression fittings you can get the tubing from the bottom of the tank to inside the building with no joints in the tubing (usually). Run both the suction and return lines to within about 3-4" of the tank bottom. Then use all flare fittings on the rest of the joints. (the comp. fittings on top of the tank are not sealing an oil joint the tubing runs straight through). Then you know the underground is good.

Then you can pressure test the indoor section. Use a bicycle pump to build some pressure if you have nothing else (co2. air compressor or nitrogen).

I'm sure this is what you don't want to here but foam in the oil is a dead giveaway of a suction leak if the vacuum is normal. The only time foam is "normal" is with a really high vacuum and that means a restriction or to much lift.


ED

Big Johnson_2

Thanks Ed

I connected my new lines to the old ones where they came up from under the house. The system I replaced was 43 years old so I think it would be a good idea to dig it up. This has been quite a porject. I do industrial heating and refrigeration for a living and had no idea what I was getting into with a 90 year old house and all that comes with it.

Eddy

New Tank

The tank is under ground, beside the house. I have a feeling the copper lines were buried and then they punch through under the house, post and pillar with a dirt crawl space. I'm considering a new tank above ground. I don't think the tank is a problem, yet. It doesn't leak and I don't seem to have any water problems. If I get a new tank, it will be above ground, for sure.

Steamhead (in transit)

It might have to be above ground anyway

many local governments now prohibit new underground tanks, and some insurance companies won't insure them any more.

Go ahead and get a new tank, and have the old one "abandoned in place" if that's permitted in your area.

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Ken_40

Mistaken dbl post

Ken_40

Hang on a minute...

There are multiple things you can try before throwing in the towel.

First, you CAN pressurize either line easily with air! By simply putting a small amount of air pressure on the line, a soap-bubble test can be done on all parts of the lines and fittings above ground. The pressure required to push the oil out and have air enter the tank bottom (where the lines end) would induce roughly 2# of test pressure (assuming the tank is near filled; 1# of pressure if half full; PLUS THE RESISTENCE TO AIR PRESSURE FROM THE SMALL DIAMETER OF THE TUBING AS WELL!

Do not assume only fittings need to be tested. Soap the entire suction/feed line.

If that shows no leaks, consider switching the return line to the supply! Presuming the lines were installed properly, the return line would be a few inches above the supply, but still well near the tank bottom and merely make your 550 (or whatever size it is) "miss" the bottom few inches the supply would commonly suck from.

Sure beats digging up the world or a new 275 in the basement, right?

Of course, if neither of those tricks works, you have few other choices. The Tiger loop would also work a lot better if the fuel unit bypass plug were removed, and the return outlet port plugged. This would minimize foaming, since the volume of the Tiger loop would see is only what your firing rate is. Or did you already do that when installing the TL?

Big Ed

Tank

You never can tell if a old buried tank is leaking a little . Most find out when it leaks a lot. "Gee , I just had the tank filled last week.I couldn't have burnt it all in April ?Maybe the oil driver ripped me off !! Grrrrrr" It could be leaking a 100 gallons a year and you wouldn't know....



90 year old house.I love them grand old ladies... You first have to fall in love..Then you better be rich or young and stuped to buy it..


I am sure your the fir$t type mentioned..

Eddy

Well, Ken,

I installed the Tigerloop according to directions ( I know, real men don't read the directions). I left the return by-pass plug in and piped it back to the "Loop." At this point I think that digging up my lines might not be a bad idea. The depth and length of run appears to be managable with only hand tools.

Eddy

None of the above Ed,

I'm neither rich nor young, just married and maybe a little stupid.

Ken_40

Well,

You obviously did the right thing in reading the destructions (:-o)

Just don't lose hope of finding the air leak. The easy digging sounds like the ultimate solution.

And, it would not be the first time somebody turned the soil near the flower beds and stabbed the oil line with a spade tip...