I'm still confused about how this happens, but I talked to CAT technical support and they said that it is possible. My pump stands are about 20 years old and were made by Magic Wand. There is gravity feed from the rinse tank for rinse,
soap and wax. There is also a fitting/connection for city water that runs to/through the rinse solenoid. In trying to figure out this problem I realized that the rinse solenoid is not wired to anything in the pump stand electrical box. This is true for every pump. The wires from the rinse solenoid are terminated with a wire nut. Any thought to why this might have been done?