Eliminating a Pressure Tank on a Lake-Fed Irrigation Pump

Switch to a Pump Start Relay for Simpler, Reliable Operation

A pressure tank on an irrigation pump adds complexity and failure points. You can run the pump directly from the controller using a pump start relay (contactor).

How to Convert

1. Remove the pressure switch and tank.
2. Install a pump start relay wired to the controller’s P/MV terminal.
3. When the controller activates a zone, it sends 24 VAC to the relay, which closes the high-voltage circuit to the pump.

Leak Consideration

If the system loses prime after sitting, the existing leak (likely a check valve or pipe joint) must be fixed. Try the shampoo trick: add a cup of shampoo to the pump, run overnight, and look for foam bubbles at the leak site.