New Roth oil tank - weird problem during first fill

chapchap70_2

A ventalarm has a narrow tube that sticks into the tank about six inches. When the oil (usually foam) reaches the tube, the whistle stops whistling and you will hear a gurgling sound. If the tube has not been cut, the tank usually can be filled for about 10 seconds without it filling up the vent. Conscientious drivers will shut the flow of oil as soon as the whistle stops.

If the tank pipe connections are not tight and sealed, they will leak with only slight pressure. A new properly installed tank should not be able to build enough pressure while filling with a standard oil truck for oil to burp out when a driver disconnects the hose from the fill pipe.

I delivered to an outside Roth tank with a silver OEM ventalarm. I did not realize that the manufacturer's name was branded where it can not be seen unless the ventalarm is lifted out of the tank. Since it was outside and all the vent piping wasn't there, I unscrewed the ventalarm for the delivery and watched the oil level from the gauge and through the top of the tank. The ventalarm was not working properly and I would have had to fill the tank more slowly if I left it alone for the tank not to build up more pressure than I like.

Pete_18

I had to have a new oil tank installed a couple of weeks ago because my old Steel tank crapped out. We had our first fill today with our new Roth tank and something very strange happened during the fill. I wanted to run it by you guys for thoughts.

During the fill, the vent whistle was going. At the end, I began to hear gurgling/whistle change and immediately the oil delivery man stopped filling. When he took off the fill hose after stopping, a couple seconds later, maybe about a 1/4 - 1/2 cup of oil spurted out at him through the fill pipe (Not the vent pipe).

In addition, a very small amount of oil leaked out of the fill connection on top of the Roth that was not tightened properly. (I am not sure if this came out at the same time or during the fill because I didn't notice it until after the fill was complete)

Here are some facts:

1. The plastic rings on top of the Roth were not tightened properly by the installer. This has now been corrected.

2. Tank is pitched pretty even, but unfortunately ever so slightly towards the fill hole and away from the vent.

3. Order of holes are: Fill, Filter/Burner, Vent, Oil Gauge

4. Fill pipe is pitched slightly towards the tank

5. Fill pipe is fairly short -- maybe 4-5 ft (I didn't measure it) -- it's many feet shorter than my old fill pipe

6. Vent pipe is a few feet longer and a little taller than the fill hole.

7. No oil is backed up in to the fill line.

8. After the tank was filled, the gauge is reading half way between 7/8 and Full.

Anyone have any thoughts what could have caused the oil to explode back? I am worried about the next delivery.

chapchap70_2

Pressure

It seems that their was a restriction in the vent causing the tank to have pressure. I have found that the ventalarm (whistle) float sticks to the seat in the newer OEM/King ventalarms which would mean the air only has an about an 1/8" hole to escape through. I can tell by the (higher) pitch of the whistle if there is a restriction and reduce the flow of oil when delivering. My guess is this pressure would only be around 2 psig, which would seem to be enough to burp back out through the fill pipe.

I have heard a Scully (209 I think) ventalarm is better.

Charlie Masone

Roth tanks can be over pressurized by trucks that pump too fast, the Roth tank will bow out during that kind of fill and I guess that as the tank came back to shape it "squeezed" out some oil, check with Roth about the maximum fill rate for you're tank.

Pete_18

Thanks for the replies.

Is there any way to determine if my vent alarm is restricting air venting too much or if the truck pumping too fast caused the issue? I have asked the oil company to pump slower in the future, but this pumping speed is what they use for everyone else and it doesn't seem to be causing a problem for anyone else. I'd like to just make sure that whatever caused this over pressurization problem doesn't happen again.

chapchap70_2

If there is no restriction, there is no increase in pressure. Since air can be compressed more easily than liquid, only a severe restriction can cause any significant increase in pressure no matter how fast oil goes into a tank. For example, 2" opening going in the fill and 1/8" opening coming out the vent. Assuming the tank is new and installed correctly, I think the culprit is the ventalarm. If the tank happens to be overfilled, the liquid should push up the sticking float which would increase the opening.

If it were me, I would tell the oil company to replace the King (silver I think) or OEM (blue) ventalarm, (I believe they merged) with a Scully (209?). The King/OEM ventalarms are more common because they are cheaper. You should be able to read the manufacturer stamp on the ventalarm located on top of the tank where the vent pipe firsts connects.

Al Corelli_2

Vent

What size piping is on the vent?

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Pete_18

It's the same size as the fill, which I believe is 2".

I can't see any information on the vent, but it appears to be silver in color.

Paul Fredricks_3

You have to, HAVE TO!!! use a Roth vent alarm on Roth tanks. They sit lower than other vent alarms so they stop whistling sooner. We had a major problem due to an installer who used OEM vent alarms. The result was an over filled tank, oil in the basement, and a freaked out customer who went to the hospital due to the fumes.

chapchap70_2

Were all the tanks with OEM ventalarms overfilled or just the one? If it was just the one, it would seem that the driver waited too long after the whistle stopped to turn off the nozzle.

Pete_18

Looks like the top for both the vent and fill has a bushing which takes it down to 1 1/4 and it stays that way all the way outside.

Is it normal for there to be a small amount of expansion of the metal on one side of the tank? It's barely noticeable, but it does appear the over pressurization (unclear what caused it so far) did cause a little expansion of the metal outer tank.

Paul Fredricks_5

Here's what happened. This is with 2 Roth's twinned together and using their crossover assembly. The crossover doesn't equalize the tanks while the units are running. The OEM vent alarm doesn't reach into the tank as far which allows the tank to be filled to a higher level. Our guess is that right after the tank was filled the units started running. Due to the design of the crossover the return line only goes to one tank. We assume the tank was very full, then the units running caused the first tank to overfill, causing the leak.

I have no idea if this has anything to do with the original issue in this thread. I'm still half asleep and don't want to think that hard.

chapchap70_2

Pete,

You seemed too concerned about this. The Roth is a tank within a tank. The outer (metal) part that you see wouldn't have been pressurized unless there was a breach in the inner tank. As little as 0.5 psig could have caused what you described. There should be a little green cover you can see in with a float disc inside. If that disc is on the bottom, there is no oil in the outer tank. I doubt this could have happened going by the info you gave unless the tank was defective from the factory.

By the way, the burp outside will happen when any tank is slightly pressurized, not just the Roth. If the ventalarm is not the one specified in the manufacturers instructions, tell the company to replace it with the one that is.

Pete_18

Thanks for the additional information. It was just a little concerning that after my first fill I found oil coming out the top of the tank (fill connection) such that I had to manually clean it out and that i had to go outside and clean up oil that had burped in to my garden. I want to do everything possible to ensure that this does not happen again in the future.

If a gurgling noise is heard at the end of the fill, does that mean that the tank has been overfilled and a little oil is making its way up the vent pipe?

freesoul

Filling a single tank?

I have a single Roth tank and am not sure about how to fill it- I was pumping some fuel in yesterday and I had to go really slow as it was backing up the 2" fill pipe. The fill fitting where it goes into the tank is very small. What am I missing?