Using a 5 gallon container as a temporary source of heating oil

I have been letting my main tank go without filling in order to empty it for removal. It is down to 25 gallons and the pickup must be loosing contact with the oil. I can't get the new tank setup completed for a week or so, and want hot water in the meantime. I took the fuel line off the burner and put another on with a flexible hose 6 ft in length. I filled a 5 gallon container and dropped the flexible hose into it and fired the burner. Ran fine and drew with no issues. Problem is the consumption is off the charts. I watched 3 gallons burn away in 15 minutes. Seems excessive, very excessive. I ran a screw into the hose to reduce flow and it improved the rate, but I can still watch as the level in the tank drops. Am I doing something wrong? Is there a jet of sorts on the pickup?

Oil usage should be set by the nozzle installed in your burner, I can see no way a residential burner could consume this amount of oil. Does your burner have 2 oil lines going to it or one? If its a two line system, you could be drawing from your 5gal can and returning to your main tank. If this is the case and I suspect it is, take both lines and put them into your 5gal can.

I just recently installed a 12 section cast iron Buderus boiler, dual stage Reillo burner, with a pair of 5.5gal nozzles installed........based on what you typed you are burning more oil an hour then this beast is, and it has 6" supply and return piped to it.

3 gallons in 15 minutes? holy hell! My oil HWH can only burn .65gal/hr... and that's wide open... and it would pop off the T&P... or explode inside of 15 ins...

are you sure that thing isn't leaking somewhere?

It has a two line feed. I figured that was a possibility and released the saftey shutoff on the return line. Between that and the obstruction I put in the line, the flow slowed. Still seems to draw too much.

yeah, you're dumping into your old tank... otherwise you're burning about 1.5 million btu/hr....

You don't want to just shut off your return line, you will most like damage the pump in your burner, there are changes that have to be made to the pump to go from one line to two lines. I highly recommend you get both the supply and return into your 5gal can or you might be soon shopping for a new oil pump!

from two lines to one I should have typed but I am sure you know what I meant, either way get that 2nd line into your 5 gal tank or it's going to cost you one way or another.....either that or remove the plug from your pump to do the one line conversion.

Can you plumb the return line into your 5 gallon container? Then you would close the loop would not be pumping back to your tank, and you would be able to use your burner.