I have an older #2 heating oil furnace for central heating in my home. The pump it uses is a Beckett AFG. Historically it's had to work pretty hard to pull fuel from an underground tank behind the house. Just last year I put a commercial fuel filter and water separator near the pump on the inlet side, along with a one-way valve to help reduce the pump-priming times when I drain any garbage from the water separator.
The underground tank has a leak somewhere and is always filling with water. I've purchased an above ground tank to transfer fuel into and abandon the underground one. My question is, since this will have a gravity-feed affect on the pump, will that cause the pump to just constantly slowly trickle fuel into the furnace 24/7? I've heard rumors of a one-way valve that I'd need that would prevent fuel flow into the pump (spring loaded ball) that the pump could overcome and suck fuel through. I've also read about some sort of solenoid valve (that I don't see an opening for on my current pump).
I'm not very knowledgeable on this stuff so when I started seeing questions like 'is your pump a delay pump?" etc I don't know what they're talking about. I'm fine with paying a local business to come make modifications as needed but I'd like to know what modifications to ask for. If I need a replacement pump with that electric solenoid valve that's fine but I just don't know what I need, if anything.