Integrated electronic control circuit for central heating boilers - has two sections forming static contactor and temperature comparator

摘要

The electronic circuit for the control of a central heating system using hot water, is in two sections (12, 13). Section (12) is a triac regulating the operation, whilst section 13) forms the control circuit. When the thyristor (15) is energised, the voltage between point (18) and (21) is reduced and half periods are fed to the motor (17). The thyristor is energised when the temperature of the water is too low or too high. The control circuit is fed by a Zener diode (35) with a continuous trapezoidal voltage. Changes in temperature are detected by thermistor (24) in the bridge formed by resistances (32, 37, 38, 39). Resistances (38, 39) apply a reference voltage to point (40). If it is less than that at points (41, 42), the circuit trips.