If you own a gas water heater then you have probably experienced a water heater thermocouple failure. Are you wondering what a water heater thermocouple really is? Basically, more often than not, you might have seen that the gas pilot light switches off or doesn’t stay lit. When this happens it means that the thermocouple is not working. This is quite a common problem faced by all those who own a gas water heater and the good news is that it is actually quite easy to fix this problem. All you have to do is replace the existing water heater thermocouple and it is not an expensive affair at all.

So let us follow a step by step method of replacing the old thermocouple and installing the new one. One of the important aspects to remember is that the thermocouple assembly should be correctly or properly installed as this will ensure that the water heater operation is perfect. If you have even the slightest doubt about performing this operation then it would be better to get help from qualified water heater service technician.

How to Install a Water Heater Thermocouple

Step#1: The first step is to turn off the gas supply to your water heater. This can be done with the help of the gas shut-off valve, which is situated on the side of the water heater. The position for shut off will be marked.

Step#2: There is a combination gas control valve/thermostat situated on the lower front of the heater. Depress it and hold the lock tab situated right under the gas control knob. Rotate the gas control knob clockwise until it is aligned with the “OFF” mark etched at the front of the gas valve. Now the gas supply has been shut off and you can now remove the outer door.

: You can use a screw driver or a nut driver (1/4”) to loosen the screws that are securing the manifold door assembly. One of the things to remember here is that you should not lose the screws or the plastic retainer washers as they will be required to attach the manifold door back to its place post replacement of the water heater thermocouple.

Step#4: Now you need to disconnect the thermocouple, pilot tube, manifold tube, and igniter wire from the combination gas control valve. You will need to use a 7/16” wrench to disconnect the thermocouple as well as the pilot tube. You will need to use a 3/4” wrench to disconnect the manifold tube. Once the thermocouple, pilot tube, and manifold tube have been disconnected, carefully pull out the igniter wire from the button.

Step#5: Now you need to hold the manifold tube and gradually push down a little so that the manifold tube, thermocouple, and pilot tube are free from the combination gas control valve. You need to now remove the manifold assembly from the burner compartment but follow caution so that other internal parts are not damaged.

Step#6: Once you have removed the manifold assembly, use a brush for cleaning the top and bottom of the flame arrestor. It is always recommended to clean the flame arrestor inside and out.

Step#7: Now locate the retainer clip that secures the two-piece wire connector to the manifold door. Use a large flat head screwdriver to separate the clip from the two-piece wire connector.

Step#8: Now push the two-piece wire connector very carefully through the manifold door. You can slide the connector one piece at a time. Keep aside the two piece wire connector as well as retainer clip for re-installation.

: Now slowly and carefully reinstall the new two-piece wire connector. You need to ensure that the igniter wire is seated right above the thermocouple within the two-piece wire connector. Insert the connector one side at a time. Once both sides of the connector are in place, insert the retainer clip to secure it.

: Now reconnect the new thermocouple using a 7/16” wrench and the manifold tube using a 3/4” wrench. One of the important things to remember is that you need to tighten the thermocouple by hand as a wrench will be able to tighten it only one-quarter of a turn.

Step#11: Now insert the manifold assembly carefully into the combustion chamber. Once inserted, ensure that there is no fiberglass insulation between the combustion chamber and the gasket. Securely tighten the screws that hold the manifold door assembly.

Step#12: Turn on the gas supply and check the gas pilot light.

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