Liquid sensing arrangement for beverage machine

A beverage machine comprising:

• a liquid supply tank configured to hold a liquid for forming a beverage;
• a heater configured to heat the liquid from the liquid supply tank;
• a first conduit fluidly coupled to the liquid supply tank, and a second conduit fluidly coupled to and upstream of the heater, the second conduit being downstream of the first conduit;
• a pump fluidly coupled between the first and second conduits, the pump configured to move liquid from the liquid supply tank to the heater;
• a first sensor configured to detect liquid in the first conduit;
• an optical sensor configured to detect liquid in the second conduit;
• and
• a controller coupled to at least one of the first sensor and the optical sensor and arranged to receive a signal from at least one of the first sensor and the optical sensor, wherein the controller is configured to prohibit at least some beverage machine functions when the at least one of the first sensor and the optical sensor detects absence of liquid at at least one of a level in the first conduit and a level in the second conduit, wherein the controller is arranged to prohibit activation of the pump when the at least one of the first sensor and the optical sensor detects absence of liquid at the at least one of the level in the first conduit and the level in the second conduit.