oil pump

fortsaine

Why might you use a 2-stage, 2-line fuel oil pump?

Jean-David Beyer

Why I did, not necessarily why I should.

I had a 1000 gallon in-ground oil tank about 40 or 50 feet from my boiler (at ground level). When they put that tank in, they had a one-stage oil pump (Beckett burner at the time) that just did not manage to get enough oil in cold weather. IIRC, it took too long to get oil, so it failed to start. They replaced it with a 2-pipe system, and that worked.



Years later, the pump developed a leak inside (no oil leaked out, but when the boiler stopped firing, oil ran bact to the tank so it had trouble starting because too much air in the lines. The tech figured this out and said the pump needed to be replaced. All he had on the truck was a 2-stage pump, so he put that in. That worked fine, of course.

Big Ed_4

Two Stage Pump

Gasses come out of solution under a vacuum . Gasses start to pull out of oil above 5" Vacuum. When the gasses enter a single stage pump it causes cavitation and loss of power . On a two stage pump the second stage of the pump blows the gasses past the pump on a two pipe system . Many ways to drop the vacuum too .. Any hight between the level of oil and oil pump over 12 feet (and that could be a stretch ) a lift pump is needed . Added note , Any oil supply 12' above pump an Oil Safety Valve is needed ....



I think this is a two part question....The two pipe system is used to keep the oil system primed . If a one pipe system is used , any air that enters the lines would have to be taken out manually ...