Knowledge of Thermocouple

The electromotive force is caused if the point of the thermocouple is heated with the burner, and the current flows to the coil of the magnet unit. 

Under such a condition, the contact pole piece of the magnet unit is pressed against the magnet by the push rod and it absorbs the magnet by magnetism. 

Even if release the push rod the gas passage will keep opening. Under such a condition, the thermocouple point gets cold when the flame disappears, and the electromotive force is not caused. The valve doesn't adsorb contact pole piece by magnet, and the gas passage is intercepted by valve returned with the elasticity of spring.

If bears of high importance to use correct inethod for installation and maintenance of the thermocouple these type of thermocouples are used in various appliances such as gas stoves space heaters water heaters and central heating systems therefore installation and maintence should be correctly observed.

A: Thermocouple set should not be critically twisted and bent which would create breakage in parts Maximum radius in bending should not be less than 15mm.

B: Distance between thermocouple and burner must be such that only 5mm of the tip, hot junction area to be placed into the effective flame.

C: If the flame moved far from the Hot Junction and close to the Cold Junction If would create less temperature difference between the two points resulting less effective EMF and lowering efficiency of the system.

D: Installing thermocouple tip parallel to two flame is not recommended, but if should be placed at the center of the flame as (a) below.