De Dietrich 88014711 limit thermostat 80C

This limit thermostat, rated at 80°C, belongs to the category of mechanical safety devices that interrupt the electrical circuit when the temperature at the sensing point exceeds the set threshold. Unlike NTC sensors which send a variable signal to the control board, limit thermostats act directly: they open or close a contact, typically breaking the burner power supply or the pump circuit to prevent overheating. Such thermostats are usually fitted on the boiler flow pipe or inside the heat exchanger casing, and they often have a manual or automatic reset function depending on the design. When selecting a replacement for a limit thermostat of this type, key parameters are the switching temperature (here 80°C), the reset mode — manual reset devices require a technician to physically press the button after the fault is cleared, while auto-reset types re-close once the temperature drops below a differential — and the mounting form (immersion stem, clamp-on, or surface-mount). The electrical rating (voltage and current) and the number of poles (normally closed or normally open) must match the original application. Typical failure modes include welded contacts (stuck closed) or loss of switching accuracy over time, which can lead to insufficient safety margin. Always verify that the new thermostat’s switching point and reset type are identical to the defective part before installation.