A limit thermostat is a safety device designed to open or break the circuit in high temperature or high current situations. They are rated for both current and temperature.

The liquid level control board is an electronic device designed to automatically fill the brew tank with water when it senses a low level condition. It works in conjunction with the Liquid Level Probe and tank ground. A low AC signal is applied to the probe from this board. Minerals in the water complete the path from the probe to ground. When no ground is present and the machine is “on”, the liquid level board will then send a signal to the refill solenoid to energize. It will de-energize when the probe again senses water.

The liquid level probe is a sensor that monitors the water level in the tank. When water comes in contact with the probe it completes the circuit to ground. Once the circuit is complete the control board knows the take is full and opens the refill circuit shutting off the incoming water supply.