Roth Oil Tanks

Billduffy

I have a dual Roth oil tank system-two 275 gallon tanks that fill simultaneously. However, only one tank is sucking oil. The other remains on full. What is the problem?

Intplm.

They might be piped so that one tank favors the other. I would post some picture here of the supply piping to the oil burner from the tanks. Some close ups and further away.

EBEBRATT-Ed

If the suction lines coming out of each tank are tied together the tanks should equalize. Is you burner hooked up 1 pipe or two pipe? Pictures will help

EdTheHeaterMan

One of the fuel lines to the burner(s) has air in it. You need to create a syphon in the tank to tank fuel line so the fuel will be at the same level as one tank level gets lower the other tank syphons over to the other tank.

If one of the tanks ever runs out of fuel and the surface falls below the pickup lone of the syphon, then air will get in and break the syphon. You will need to reestablish the syphon again if that ever happens again. Sounds like you have to reestablish the syphon.

Can you take a picture of the top piping of both tanks so we can see how the Fill pipe, The vent pipe and the fuel lines are connected together?

Illustration to follow

EdTheHeaterMan

Is the supply fuel piping from the tank to the burner(s) installed properly?  Are all the fittings air tight?  Since you need to draw from the bottom of the tanks, both supply pipes need to go to the bottom of the tank, and the Tee fitting where both pick-up lines connect and proceed to the burner(s) must be as close to centered as practicable.  See this illustration and figure 5.4 from the installation manual. 

You may have a leaking fitting on the supply intake of one of the tanks. That will cause the tank without the leaking fitting to bull more fuel during burner operation and will break the syphon when the burners are off so the tanks do not have a chance to equalize

mrcoder

A picture or some more detail on how the tanks are plumbed would be helpful. Without more info, any answer would be just a wild guess. E.g. How do these tanks "fill simultaneously"?
Do they have a connecting pipe at the bottom?

For example, I have a similar setup, with 2 separate fills and whistles, and 2 x 1/2" strait copper tube uptakes. These are run into a Y joint, into a 3/8 line, and finally into a tigerloop next to the burner. In this case care was taken to make sure that the lines going into the y joint are of equal length and diameter.
If you have a similar setup, one of your uptakes could be plugged. If so, I would blow it out w compressed air, but make sure you do not have a check valve first. If you have an air leak somewhere, you would have periodic lockouts, which you are not complaining about. Is this a new install, or the problem developed later?

Big Ed_4

The one suction line inlet is plugged with algae growth ..

mrcoder

@Big_ed_4:
We dont know for sure, but perhaps the op has overhead uptakes?

The one inlet for an overhead line would be a few inches above the bottom (and any water accumulated in the tank). Without water, I expect there could not be algae growth, right?

HydronicMike

This needs to be corrected and tank levels need to be equal before your next delivery or could potentially have a disaster on your hands.

This is why when I install two Roth tanks they get separate fills. Vents can be twinned, but not fills, for this very reason.