Vaillant Eco Tec Plus & Pro Main Heat Exchanger Thermal Fuse Sensor (F76 Fault)

📌 What these parts are F76 Thermal Fuse / Thermal Fuse Sensor — a safety device fitted on/near the main heat exchanger on Vaillant Thermal Fuse Sensor Ecotec Plus Main Heat Exchanger and similar parts. It detects overheating and will trigger an F76 fault code if temperatures exceed safe limits to protect the boiler’s heat exchanger. 🛠️ About the F76 error The F76 fault code means the overheating protection on the primary (main) heat exchanger has responded — usually because the thermal fuse has gone open circuit or the heat exchanger has been overheated. Some thermal fuse sensors are sold separately as a replacement part for the wiring/connector component, but in many cases the thermal fuse itself can’t be reset if it has actually blown inside the heat exchanger. If the fuse has blown due to overheating (not just a wiring defect), this often indicates heat exchanger damage, and replacing the heat exchanger — or sometimes the whole boiler — may be necessary. 📍 Common compatibility These thermal fuse sensors are generally listed as compatible with: Vaillant ecoTEC Plus boilers Vaillant ecoTEC Pro boilers (Other related ranges use similar F76 components) However, compatibility can vary by model year and specific heat exchanger design, so always check the boiler’s GC / model reference before buying. ⚠️ Tip F76 faults are relatively serious — often caused by: Blocked system or poor water flow (overheating) Faulty wiring harness to the sensor Actual main heat exchanger overheating or damage A competent Gas Safe engineer should diagnose the root cause before you fit a replacement part.