Abstract :
The use of gas sensors in two prototype boiler combustion control systems is described. The first control utilising a semiconductor tin dioxide sensor is aimed at the combination or `combi´ boiler market, in which two markedly different heat outputs are required from a single appliance. The lower heat output primarily serving conventional space heating with radiators and the higher heat output serving instantaneous hot water generation, thus obviating the need for a storage hot water cylinder. The second control is intended for future designs of boiler, where load matching to the heat demands imposed b the dwelling and its occupants is met in a more closely controlled manner than is current practice. The control matches the boiler heat output to that demanded by turning down or modulating the burner. In addition, the air supply to the burner is dynamically controlled, thus allowing the effective use of low emission combustion systems and significantly increased heating system operating efficiency. In this system an amperometric zirconia oxygen sensor is employed
