NOVELTY - The analyzer has a handheld-sized body provided with a handheld sized housing, a display, a keypad or other user interface i.e. touch screen, integral to the display, a gas sample collecting element, an in-line water trap, a filter, and a removable sensor module (350). The removable sensor module is adapted to receive a sensor chip (314). A circuitry (304) is adapted to receive sensing information from the removable sensor module. A separate sensor module replaces the removable sensor module, and senses a different type of sampled gas than the removable sensor module.    USE - Handheld-sized combustion gas sampling analyzer such as Fyrite Bacharach INSIGHT combustion gas analyzer and Testo 330 flue gas analyzer, for use by field HVAC technicians for sampling and analyzing gases in gas sensing applications in a HVAC industry. Uses include but are not limited to sample and analyze nitrogen oxide (NOx), carbon dioxide (CO2), carbon monoxide (CO), nitrogen monoxide (NO), oxygen (O2), methane (CH5) and propane (C3H8).    ADVANTAGE - The analyzer minimizes a number of sensors requiring periodic re-calibration so as to reduce cost of operation/cost of ownership. The sensor modules are utilized on the analyzer so as to test and measure different types of gas depending upon the particular sensor module installed in the analyzer. The sensor modules are configured and equipped with different sensor technologies, so that the field technician can choose the sensor modules for particular applications, compare sensor measurements using different types of sensor technologies, and easily verify sampled gas test and measurement data. The analyzer enables software to automatically interact with the calibration circuitry if the software installed in the analyzer unit so as to detect the replaced sensor module and automatically prepare the analyzer for use without user interaction beyond plugging in the replacement sensor module.    DETAILED DESCRIPTION - The sensor chip is formed as a solid state/semiconductor type gas sensing integrated circuit/chip. An INDEPENDENT CLAIM is also included for a method for utilizing a sampled gas combustion analyzer.    DESCRIPTION OF DRAWING(S) - The drawing shows an exploded perspective view of a sensor module with an associated sensor cap.    Circuit board (302)    Circuitry (304)    Sensor chip (314)    Removable sensor module (350)    Sensor cap (352)