The other check valve is behind the plywood(actually its half way through it). When vacuum is applied the tee check valve is open letting sap in from the mainline which connects to the step down side. At that time, the other check valve is sucked closed. When it releases to the tank, the tee check valve gets pushed shut and the other check valve gets pushed open by the out rushing sap. I'll try to get a closer pic if you're still not sure. Let me know. PS. The tank is on the backside of what you see.
Last edited by madmapler; 09-10-2013 at 08:08 PM.
2013-1st year...94 taps,18 gallons syrup. 12x24 sugarhouse, home built evap. Gast 2065 pump with bender
2014-30x36 sugarhouse, 2.5x10 "Jutras" evaporator, 1200+ taps on vacuum, sap brothers RO. 2 sihi 2 stage pumps