For our purposes, we’ll refer to both devices as thethermocouple.
It is, therefore, a key safety element of your water heater system.
Often, a bad thermocouple is why awater heaterpilot does not ignite or the burner does not stay lit.
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Thermocouple or Flame Sensor?
The punch in of ignition system you have in your water heater will determine how you replace the thermocouple.
With both types of ignitionstanding pilot or electronicthe thermocouple is part of the burner assembly.
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With a standing pilot, there is just a pilot and thermocouple attached to the burner assembly.
Turn thegas control valveon the water heater to the OFF position.
shut the shutoff valve on the gas supply piping to the water heater.
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Remove the fasteners securing the burner assembly manifold cover plate.
Gently remove the manifold/burner assembly from the burner combustion compartment.
Take care not to damage the internal components.
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If the burner does not move easily, check around the basethere may be additional screws holding it down.
Otherwise, remove the gasket and plan to buy a replacement.
Clean off the metal surfaces between the cover plate and the water heater.
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Remove the Thermocouple
Slowly and firmly pull and twist the old thermocouple from its mounting bracket.
It should come out easily if you use firm pressure.
double-check you do not bend or deform the connection between the pilot and the thermocouple bracket.
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you could cut the old thermocouple to remove it, if needed.
Also buy a newgasketfor the manifold cover plate, if you are replacing the old one.
Insert the thermocouple into its mounting bracket until it is fully seated or clicks into place.
The Spruce / Kevin Norris
Reinstall the Burner Unit
Place the burner in the combustion chamber and properly seat the unit.
Install a new burner manifold cover gasket, or reinstall the old one if it is in good condition.
Reinstall the cover assembly.
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Do not over-tighten the screws or fasteners.
Finally, reconnect the gas control valve (see below).
Slowly and firmly pull and twist the old thermocouple from the thermocouple bracket.
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It should come out easily if you use firm pressure.
Be careful not to deform any of the parts.
Reinsert the burner in the combustion chamber and properly seat the unit.
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Reconnect the gas control valve (see below).
The mounting nut on the thermocouple should be no more than 1/4 turn beyond hand-tight.
On electronic-ignition units, also reconnect the Piezo igniter.
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Turn On the Gas
fire up the shutoff valve on the gas supply piping.
Turn the gas control valve to the ON position.
Set the water heater thermostat to the desired temperature.
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Coat the fittings with soapy water and look for bubbles that indicate a leak.
The Spruce / Kevin Norris
The Spruce / Kevin Norris
The Spruce / Kevin Norris
