The chattering you hear on a pump start relay is usually caused by insufficient amperage arriving at the relay from the controller.  The first question you should ask yourself is – Did this Relay work for some time before or is this new installation? New …

REL 2 is used to allow multiple controllers to operate the same low-voltage device (Master Valve or Pump Start Relay).  IMPORTANT: REL 2 is NEVER connected to high voltage. It is for 24VAC devices, only. Diagrams listed below: … … … Two Controllers With …