Friday, Sep 14, 2018 at 15:35
Dave - No, a thermocouple is not a thermostat. A thermostat governs the temperature of an appliance.
A gas oven thermocouple is basically a safety switch for the gas supply.
It sits in the flame and shuts off the gas supply if the flame goes out for any reason.
A thermocouple contains a heat-operated switch (usually a simple bi-metallic switch) that keeps the gas supply open when it's being heated.
If it cools off substantially, the bi-metallic switch closes, and shuts off the gas supply, preventing gas explosions.
A thermocouple can be damaged, or fail internally, and not function properly. Usually when a thermocouple fails, the gas burner won't stay lit.
A thermocouple can simply become faulty and restrict the gas flow, so the flow doesn't reach the designated flow rate.
The gas supply line to the thermocouple can become damaged too - something else to
check on.
Another thing to look for, is whether there is some other physical restriction in the gas flow, that would stop the burner from reaching its full heat capacity.
Gas lines can become kinked or squashed - and the old mud-dauber wasps are a notorious enemy of gas systems, blocking or restricting them - where a line has been left open, even just for a short time.
Cheers, Ron.
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