A low-cost multisensor system for combustion control based on electrochemical gas sensors has been manufactured and studied. We followed simple technological steps to join three simple planar elements exhibiting complementary sensing properties. The system does not require a reference atmosphere and combines an amperometric module for O-2 measurement and two potentiometric elements for CO and NO2 detection. The working temperature of 600 degrees C was selected as a compromise between the electrochemical response signals and diffusion kinetics of the potentiometric CO- and NO2-sensing modules. We established the response and recovery times for CO, NO2, and oxygen pulses, together with their respective activation energies. For the whole range of gaseous compositions, the electrical measurements provided by the oxygen-sensing module permitted the correction of the oxygen cross-sensitivity for the two potentiometric elements. Principal component analysis has been used to show the feasibility of simultaneous detection of NO2, CO, and O-2 using this low-cost system, which reveals great promise for use in domestic gas boilers. (C) 2007 The Electrochemical Society.