The W-TC4 is a microprocessor based digital controller specifically designed for refrigeration systems. It is particularly suited for medium or low temperature ventilated refrigeration units. The temperature control is always subject to a positive temperature differential (make on rise); the compressor stops when set-point is reached and start again upon reaching the set-point temperature plus the differential. It is provided with NTC thermostatic probe input and two relay outputs for compressor and light. It is easily to calibrate sensor from –5 to +5oc. The defrost cycles can be controlled at time intervals. The value of the probe’s reading is viewed on a display by 3 digits and a minus sign