Paul -
The gear relays are activated by applying a small current to the relay coil
terminals. That pulls the main contacts closed against a strong spring. When
you remove power the spring pulls the main contacts apart. There is a known
failure mode where the main contacts weld themselves together. When that
happens the relay will remain in the "on" state regardless of what the
pressure switches are doing.

-Adam
-----Original Message-----
From: Paul Miller [mailto:pjdmiller@gmail.com]

Adam, I don't understand how this happens unless the pressure switches on
the pump aren't shutting down.

Paul