On chillers equipped with a tank level indicator the level switch intermittently indicates tank low when the tank is full or near full.
Pump cavitation can cause excessive air build up within the level switch (located in the tank) and the built in splash preventer that is part of the switch assembly.
Using the proper size hex wrench, turn the switch assembly located at the end of the tank 180 degrees CCW. Let is stay in this position for one minute and then rotate the assembly back into the original position. This procedure will release any air trapped in the switch splash shield.
Also make sure that the arrows molded into the switch assembly hex nut are pointing UP.
All PACT and EST tank model chillers with tank level indicator option.