Technical Guides & Boiler Maintenance Articles

A boiler flow meter is an active electro-mechanical transducer combining an internal radial turbine and a solid-state Hall-effect sensor to measure domestic hot-water velocity. By delivering continuous digital frequency pulses to the printed circuit board, it enables feed-forward gas valve flame modulation. This engineering guide details turbine architectures, failure signs, multimeter voltage diagnostics, and selection standards.

A boiler flow switch is a mechanical fluid-activated switch that confirms domestic hot-water demand via a magnetic reed contact. Limescale accumulation or reed contact degradation prevents burner firing or causes dangerous post-draw overheating. This technical service guide covers magnetic shuttle mechanics, bench multimeter continuity testing, and replacement rules for union-nut, two-way, and three-way configurations.

A boiler NTC sensor is a negative temperature coefficient semiconductor thermistor that monitors primary and sanitary water circuits in combi appliances. As fluid temperature increases, electrical resistance declines along a calibrated logarithmic curve, allowing the printed circuit board to execute feed-forward gas valve flame modulation. This engineering guide details 10K resistance curves, immersion versus surface architectures, failure symptoms, and multimeter diagnostic procedures.