Vaillant ecoTEC Plus / Promax Heat Exchanger Thermal Fuse Sensor (F76) – Refurbished

The F76 fault code on a Vaillant ecoTEC Plus or Promax boiler indicates that the main heat exchanger thermal fuse sensor has detected an over-temperature condition — or has failed itself, causing the boiler to lock out as a precaution. This small but critical safety sensor monitors the temperature of the main heat exchanger. When it trips or fails, the boiler shuts down and cannot restart until the fault is resolved. The Vaillant Main Heat Exchanger Thermal Fuse Sensor (F76 Fault) – Refurbished is the correct replacement for the ecoTEC Plus and Vaillant Promax ranges, resolving F76 lockout and restoring safe boiler operation.

This is a professionally refurbished genuine Vaillant component — tested and approved by our engineering team before dispatch. Minor cosmetic marks may be present. Original price: £20.99 — current price: £15.99. Supplied with a full 12-month warranty.

Part Fits

Refurbished. Tested. 12-Month Warranty.

Every refurbished sensor is tested and approved before dispatch. This unit resolves F76 lockout on Vaillant ecoTEC Plus and Promax boilers, restoring safe operation. Supplied with a full 12-month warranty.

Delivery & Returns

Orders placed before 1:00 PM (Mon–Fri) are dispatched the same working day. Standard and next-day delivery available at checkout, including Saturday. Returns accepted within 30 days in original unused condition.

Note: Before ordering, confirm the F76 fault is not caused by an actual overheating condition (e.g. blocked heat exchanger). If overheating is confirmed, the exchanger itself should be serviced first. Must be fitted by a Gas Safe registered engineer.

Product Reference