Check valve on SP-11 vacuum pump

[jwalker]

Where's a good place to go to get a check valve for the vacuum line? I have a 1'' vacuum line and want to prevent sap from backing up into pump. Will the check valves at the local hardware store work? I would think the vacuum would just pull it shut? Does it need to be a special vacuum check valve?

Thanks

[mapleack]

No checkvalves won't work to do what you want to do. The easiest thing for you to do is get a whole house water filter housing, put a racquet ball in it. Be sure to pay attention to the "in" and "out" sides, you want the the hole in the middle to be going to the pump. If sap back s up the ball floats until it seals off the port to the vacuum pump.