Riello Flame sensor 20132566 / 3007839

This is a flame sensor from Riello, designed for use in gas boilers. It operates on the ionization sensing principle, using a flame rod as the sensing element. The sensor detects the presence of a flame by measuring the electrical current conducted through ionized combustion gases. This signal allows the boiler control system to verify safe ignition and stable combustion. The SKU is 20132566 / 3007839.

Flame sensors of this type are selected by matching the electrical connection type and the sensing element configuration to the boiler's control board specifications. The ionisation rod must be positioned in the flame path, typically mounted horizontally or at a slight angle into the combustion chamber. Replacement requires noting the exact mounting bracket type and ensuring the electrode gap and resistance characteristics suit the original sensor's ratings. Always verify the connector type and polarity before installation.

When a flame sensor fails or degrades, the boiler typically enters lockout after a few seconds of operation, as the control board detects no flame signal and shuts off the gas valve for safety. Common failure modes include electrode erosion from repeated ignition cycles, fouling from combustion deposits, or electrical discontinuity in the sensing rod. A blocked or misaligned sensor may also fail to establish proper contact with the flame, causing intermittent lockouts or failure to ignite.