Thermal cut off, or sometimes referred to as TCO, is a fuse that acts in the same way as a limit thermostat. If the temperature reaches a certain level the TCO fuse will blow just the same as any other fuse, cutting power to the tank heater. The TCO is also current sensitive.

A thermistor is a temperature sensitive resistor used to monitor temperatures. It changes value as it cools or heats. NTC (Negative Temperature Coefficient) thermistors will decrease in ohms value as it heats, and are commonly used in temperature sensing. PTC (Positive Temperature Coefficient) thermistors increase in ohms value and are generally used in protective circuits by monitoring over current conditions.

A thermoelectric cooler (TEC) is a small cooling device that relies on a Peltier junction. Composed of two conductors made of different materials, a Peltier junction acts as a heat pump which can cool or warm when current is passed through it. For example as current passes through one side is hot and the other is cold. This device is used to chill, (approximately 20º from ambient air temperature), but not refrigerate concentrate product.

BUNN offers a full line of vacuum-insulated servers and brewers that brew directly into these servers that keep coffee at optimal flavor for hours and save on energy consumption and by not requiring warming plates.

The timer board is designed to provide the voltage to a specific device in order to energize it. It can energize a relay, inlet solenoid, pump, dump valve or other device for brewing or can energize a motor to grind coffee, to name a few.

The board consists of an inferred LED and a photo transistor which monitor the auger shaft and motor pin distance. The microprocessor will determine the shut off point of the refrigerant solenoid in relation to the thickness (distance) setting in the function menu.

Total dissolved solids, or TDS, is the total weight of the solids that are dissolved in the water, given in ppm per unit volume of water.

A transformer is a device used to step a voltage up or down and isolate circuits. It consists of two sets of windings (lengths of coated wires), which have no electrical connection to each other. An AC voltage is applied to the primary winding, which generates a field of flux. This action causes the secondary of the transformer to generate a stepped-down AC voltage. In BUNN equipment, 12 volt and 24 volt step down transformers are most common.

A triac is a solid-state device that performs the same function as a relay, without the moving parts. Its construction is T-1 (terminal), T-2, and a gate. Normal state of a triac is “open” between T-1 and T-2. Applying a small AC voltage to the gate activates it, which then “shorts” or closes the two terminals and allows current to pass. Because there are no moving parts, a triac has no contacts and will not “pit” and wear out like a relay can.