Thermocouple LF L3440034

A thermocouple pilot probe converts heat from a gas flame into a small electrical current that holds the gas valve open. When the flame fails, the current stops and the valve closes automatically, cutting the gas supply to prevent leaks. This safety device is fitted to gas fryers, grills, hobs and other catering appliances that rely on a standing pilot light to ignite the main burner.

The probe threads into the appliance and extends into the pilot flame. Heat at the junction of two dissimilar metals generates a voltage that keeps the gas solenoid energised. If the flame goes out, the voltage drops and the solenoid shuts off the gas within seconds. The operator does not intervene; the system is self-monitoring and fails safe.

To install, the engineer removes the old probe, threads the new M9x1 fitting into the gas valve body, and routes the 500 mm lead to the pilot assembly. The probe tip must sit directly in the flame path without touching the burner. Once secured, the appliance is relit and the pilot flame checked for steady, blue combustion. The thermocouple is not adjustable; its position relative to the flame determines the signal strength.

The probe is a single stainless-steel rod with a threaded brass fitting at one end and the thermocouple junction at the other. The 500 mm length allows it to reach from the gas valve, mounted low in the appliance, up to the pilot burner at the top of the chassis.

The M9x1 thread matches the standardised pilot valve ports used across the listed brands. The 500 mm length suits the internal routing of fryers, grills and hobs where the valve sits below the cooking surface and the pilot is mounted above it.

Cleaning is limited to brushing off carbon deposits from the probe tip during routine burner maintenance. The probe itself is not serviced; when the signal weakens or the junction fails, the unit is replaced.

This LF article L3440034 is a direct replacement pilot thermocouple for the gas appliances named in the compatibility list. It is stocked in the catering spares section under gas safety controls.