✅ Thermocouple for Saunier Duval water heaters, used as a safety component to monitor burner flame.
✅ Compatible with Saunier Duval Opalia C6 water heaters and other units using the original reference S1203700.
✅ Technical function: when the flame is detected, the thermocouple generates a thermal signal that keeps the gas valve open; if the flame goes out, gas supply is automatically shut off.
✅ Replacement recommended when the heater will not hold the flame, switches off when the control knob is released or shows intermittent ignition issues.