Shurflo Vaccuum ircuit

[toothfairy050]

I am working on vacuum system and wondered if I installed one normally open and one normally closed solenoid valves on the tree side of the Shurflo pump so that when the temp controller shut the pump off it would close the N/O valve and open the N/C valve to create an automatic transfer allowing gravity to take over?

[SeanD]

Yes, that works and it's the principle behind the S3 controller system Mountain Maple makes. You'll only need one valve, though. If you put the pump on the bypass branch and the valve on the direct line to the tank below or past the branch, it will open and drain to the tank on gravity or close and the pump will pull the sap up into the bypass line and then dump into the tank.