I use a 3 hp deep pump strictly for filling a pond used for irrigation. The pond level is controlled by a Ametek 1500-G-L2-S7 liquid controller. It has always been used to stop and start a 24v sprinkler valve. Due to much maintenance I disconnected the pressure tank, pressure switch, and electric valve and now pump straight to the pond. I now use a 24/240 volt contactor. It works fine using the 24 DC transformer. The problem is when you install the Ametek controller between the transformer and the contactor, the contactor chatters, and stops and starts rapidly. Nothing is loose and all connections are tight. Could the contactor be too strong, although it works fine from the 24v trans?