Duplex oil tanks not filling equally

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  #1  
Old 01-27-13, 03:02 PM
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Duplex oil tanks not filling equally

I have a pair of Roth oil tanks which don't fill equally. I got a 400 gallon order today on a nearly empty pair (2 x 275) and the meters show about 7/8ths on one and a little over 1/4 on the other. (hmm, should I wonder if the delivery was actually 400 gallons, 1 + 1/8th x 275?? I didn't use our regular oil dealer ...)

I think the piping was done correctly and the installation is level enough that I don't think there is a leveling issue. They're a few years old, and I havent' had them serviced. I recall the last time they were filled (this was a limit order) , they also were uneven though not as much. I wasn't in the basement when the deliveries were made so I have not listened for the whistles, guess I should do that if I want to narrow down what happens better. Another minor issue, when the tanks are filled, there tends to be an oil smell and a little bit of apparent leaking around the top of the tank - not a lot, just a few drops and I suspect that is because one tank is under full fill-rate pressure when the oil flows into the back tank.

The tanks do seem to be piped like the duplex in the diagram a the link below, except as Roth tanks, the pipe to the furnace comes out of the top of the tank. But the fill value looks like the one in the illustration.

http://inspectapedia.com/oiltanks/Au...de122-DJFs.jpg

Is it normal for tanks in a duplex arrangement not to fill evenly, particularly with a partial fill? Should the furnace, which is a fairly recent Thermo-pride that has two oil lines going in, one from each tank, be eventually able to equalize the tanks?

Thanks for any pointers,

Charlie
 

Last edited by Chaz; 01-27-13 at 03:04 PM. Reason: (Added comment about delivery volume)
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Old 01-27-13, 04:20 PM
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Are your shut off valves both open? If so, they should equalize. Which direction is the three way valve pointed?
 
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Old 01-27-13, 04:26 PM
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Two lines will equalize the tanks but it could take a long time with only a 3/8" line.
 
  #4  
Old 01-28-13, 03:07 PM
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Roth has kits for multiple tanks which are designed to ensure proper even filling. I'm pretty sure I remember during training the Roth rep said their system was engineered to fill up to a 16 (or some other ridiculous number) tanks evenly with one supply and vent line. If you have the proper kit then perhaps a blockage in one tank's vent/fill...

Here is a link to the installation manual
http://www.roth-canada.com/cae/pdf/D...7-07_Final.pdf

Here is a pic of the proper kit/setup for multiple tanks, about 1/3 down the page.
Fabco, Inc. - Environmental and Utility Contractors. Long Branch, New Jersey
 
  #5  
Old 01-28-13, 07:56 PM
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Every time I've installed multiple Roth tanks, I've used separate fills since the fill pressure & flow rate is so critical. You never know what the flow rate or pressure is from delivery company to delivery company or even from driver to driver.

I also belive that diagram from inspectapedia to be in conflict with NFPA 31, the code regualting installation of oil burning equpment & oil storage tanks. Not being from MA, I'm not certain about their codes but they tend to be some of the most strict in the country.

Short answer: I believe the unequal fills to be a result of a partial. The tanks may eventually equalize but it will take quite a while, if ever.
 
  #6  
Old 03-14-14, 06:42 AM
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Followup

OK, so it is more than a year later. I figured out that one of the two meters seems to be sticky, by tapping on the meter and seeing it jump to approximately the same level as the other tank.

Fast forward to now, when I need to fill again this spring with high oil prices so I'm trying to get the last few days out of my fill before ordering. Saved 10 cents today! So the question for this winter is, now I see one meter which is well down in the reserve area, while the other is measuring closer to a quarter full, on a pair of Roth tanks. I'm not positive if these are installed as recommended, but what I see is two supply lines feeding to a Y that is on one side of the oil filter. So the question for today is, do I need to fill when the first tank is showing close to the end of the reserve area, or can I go until the second one is below an eighth full? Looking at the pipes, I'm imagining that it will start sucking air from the empty side rather than continuing to draw more or less evenly.

Thanks for any help if anyone sees this.

Charlie
 
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Old 03-14-14, 11:40 AM
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I'm imagining that it will start sucking air from the empty side rather than continuing to draw more or less evenly.
I'd have to agree with that conclusion too.
 
  #8  
Old 03-14-14, 04:37 PM
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Chaz,
Hot and Cold: Roth Oil Tanks - YouTube
This is a YouTube clip on installing 2 tanks with the special kit you need.
You might find it interesting.

Good Luck,
 
  #9  
Old 03-14-14, 06:53 PM
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I wonder how much Roth paid that guy for that commercial. Why anyone would want to store two years plus of oil is beyond me. The longer you store it, the more bacterial contamination you are going to have. Unless Roth has changed, if you have a failure & have used any kind of fuel treatment, your "warranty" isn't worth the paper upon which it is written. I've seen it happen.

Charlie, If it were myself, I'd eliminate one of the tanks.
 
  #10  
Old 01-22-16, 12:28 PM
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And another followup

It seems one of the two meters is busted. Perhaps the float string got tangled up, or something like that.
 
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