What Is A Thermocouple

 

A thermocouple is the joint of 2 dissimilar metal strips that produces a voltage related to temperature.

 

 

How Do Central Heating Systems Use Thermocouples?

 

Central heating boilers use thermocouples to tell whether the pilot light is lit.

 

Thermocouples are safety switches that remove the gas supply to a pilot light when the pilot light is not lit.

 

· Thermocouples produce a voltage when hot.

 

· The pilot light, when lit, heats the thermocouple – the thermocouple produces a voltage.

 

· When the pilot light is not lit the thermocouple does not produce a voltage.

 

· The central heating boiler detects that there is no voltage (pilot light is not lit) so either tries to relight the pilot light or turns the gas supply to the pilot light off.

 

 

 

What Can Go Wrong With A Thermocouple

 

What can go wrong with a thermocouple:

 

· The join between the 2 dissimilar metals ‘breaks down’ into one metal.

 

· The voltage output wires break.

 

A thermocouple is cheap, about £5; it not worth repairing a thermocouple.

 

A thermocouple takes about one hour to fit and test.

 

 

 

Links

 

Main Central Heating Web Page

 

Central Heating Timer Problems

 

Thermostats       

 

Central Heating Boiler Problems

 

Hot Radiators Upstairs But Not Downstairs         

 

Central Heating Boilers

 

Central Heating Troubleshooting Tips        

 

Judge Electrical Ltd Central Heating Guideline Prices

This webpage describes:

 

· What a thermocouple is.

 

· How central heating systems use thermocouples.

 

· What can go wrong with a thermocouple.

 

 

 

 

 

 

 

Thermocouple

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