Beretta NTC sensor TPI50100R

This is an NTC temperature sensor manufactured by Beretta, with catalogue number TPI50100R. It fits Beretta CIAO 24 CSI N and CITY 24 CAI/CSI boilers. The sensor measures water temperature and sends the signal to the boiler control board. The control board uses this reading to modulate the burner output, adjusting the fan speed or gas valve to meet heat demand. Its sensing element is an NTC thermistor.

Temperature sensors of this type are selected by their resistance characteristic, typically 10 kΩ or 12 kΩ at 25 °C, and by the probe form, which may be immersion, clamp-on, or sleeve. Cable length and connector type must also match the existing installation. Before replacing, compare the resistance curve with the original specification, inspect the cable for damage, and ensure a clamp-on probe is in firm thermal contact with the pipe.

An NTC sensor can develop a drifting resistance characteristic, causing the boiler to modulate the burner incorrectly. A break in the cable interrupts the signal, and a clamp-on probe that loses thermal contact with the pipe gives an inaccurate temperature reading. Checks include comparing the resistance curve at ambient temperature, inspecting the cable for damage, and verifying the probe is firmly attached.