My pump is on the floor.  Pulling out of the inside tank about 5" above the bottom.  The tank is supposed to be full (3' or so) at all times, but if our storage tanks get low it isn't.   That's when stuff starts acting up, especially if it's zero outside.  We removed a couple restrictions in the lines from outside this fall, and that has helped.  Intend to raise the storage tanks 3 feet or so and then I think we will have no more of that trouble as the inside tank will stay full until the storage is completely empty. 

My pump and pressure regulator are not Lanair.    Just a little gear pump and a spring type sprayer regulator. I have double staged regulators on the air.  If I try to run a single regulator I can't keep it from freezing up when cold outside.  Our storage tanks are outdoors, the entire system is in an open door van body...stays 40 or so minimum.  We had doors on it, but it would never run consistantly that way because it had no source of combustion air. 

Abuot 15-20 on air, not sure on oil at the tip because the gauge has been overpressured.  It reads about 6 psi with the pump off, and I run it about the top of it's range.   I'm guessing it is about 10-12.  We are fueling it about 150% of what it is rated to burn.  That's about as far as i can push it and have it run reliably.  Can go to 200% if I'm there to keep an eye on it.