556301 Manopola per termostato 556301 TR2, OEM

This article is listed as a handle thermostat under catalogue number 565.700.900 with manufacturer codes 556301 and 565.700.900. The name indicates it is part of the TR2 series and is marketed as an OEM component. Temperature sensing in a boiler system closes the control loop. NTC sensors report flow, return, cylinder and outdoor temperatures to the control board, while mechanical thermostats and limit switches act directly on the circuit. A handle thermostat of this type typically includes a manual adjustment knob and a switching mechanism that opens or closes contacts at a set temperature. Such thermostats are selected by their switching point, reset type (automatic or manual), and the mechanical configuration of the probe or sensing element. Common failure modes include drifting of the switching characteristic, which causes incorrect boiler modulation, a broken internal cable, or poor thermal contact between the probe and the pipe. When replacing a handle thermostat, verify the switching temperature and reset behaviour match the original. Also check the probe form: immersion, clamp-on, or sleeve type. The cable length and connector type must be compatible with the boiler wiring. If the thermostat is used as a limit or safety device, ensure the reset type (manual or auto) is appropriate for the application. No further technical data for this specific article is available in the source information.