two-pipe installations up to 17" hg. vacuum lift or gravity feed applications with 10 psi maximum inlet/return pressure adjustable manual or automatic high/low firing high efficiency burner applications capacities to 23 gph pressure adjustable (100 to 200 psi low fire, 200-300psi high fire) for no. 2 fuel oil. for other fuels, consult factory two-bolt flange mounting in any position exceptupside down. note: rotation (rh = cw) & nozzle location determined by looking at the shaft when unit is oriented with shaft horizontal and decal readable (regulator valve on top). made in the usa .