REGELEINRICHTUNG FUER EINE BRENNSTOFFBEHEIZTE WAERMEQUELLE

摘要

A central heating boiler serves a heating system and provides primary water for a domestic hot water calorifier. Its output is controlled by a solenoid valve (12) in the gas supply to give priority to the domestic hot water demand. The water temperature is determined by a variable resistance which forms part of a bridge circuit. The desired valve is set by two branches of the bridge which each contain a variable resistance one of which is connected with the water detecting resistance to a comparator. The comparator controls the current to the solenoid. A network of diodes blocks the signals from the branches of the bridge which are not required in any particular control mode.