Central heating system with thermostatic control of gas to burners - feeds high current through series resistor for thermal switch with relay

摘要

The central heating system has a temperature regulator which consists of a thermostatic switch and a series resistor to control the gas supplied to the burner of the boiler. The resistance is variable and is thermally coupled to the switch of the thermostat. The thermostat is incorporated in a control circuit(4) and the switch(2) controls the switching element(5) which controls the gas supply valve (6). When the switch is closed, the current through the regulating circuit and through the series resistance is high to generate heat in the resistance which will affect the thermostat switch. The control circuit has a separate voltage source (7). A switching element consists of a relay (11) in series with the thermostat.