Linear central heating control system - includes linearity compensating system with outdoors and feed water temp. sensors

摘要

The central heating system has a temperature sensor (19) in the supply line (14) from the four way mixer valve (13) to the equipment being heated, the return line (16) being connected also to the valve (13). This sensor is connected to a linearising network (21), an adder (25), a linearity compensating device (36) and a differential amplifier (37) to a stepping motor (39) for the valve. A second temperature sensor (20) responding to temperatures outdoors is similarly connected by a linearising network (22), adder (26), an inverter (33) and a mutual conductance unit (34) to the differential amplifier (37). Between the two adders is connected a room temperature adjusting switch (30) between two variable resistances (31, 32). The system ensures a linear control of the flow of hot water to the radiators.