Control apparatus for gas burning appliance

摘要

A control apparatus for a fanned, gaseous fuel-burning appliance, such as a water boiler for a domestic central heating system; the control apparatus includes electrical circuitry comprising first and second changeover switches each having a normally-closed pair of contacts and a third, normally-open contact, and a third switch; the switches are connected in a particular way to actuate gas valves and the fan of the appliance in a manner which provides improved safety features.