How to Diagnose and Fix the Water Heater Thermocouple

Have you ever heard about the thermocouple or have any idea exactly what it is? Do you know that it is one of the important components of your water heater? Sometimes when the thermocouple breaks down you may think that the water heater needs replacement. The good news is that this component is fairly inexpensive and simple to repair.

water heater thermocoupling

Diagnosing the Problem

Before you can actually diagnose and identify that the problem has something to do with the thermocouple, you have to know where it is located. Within the burner compartment just in front of the pilot light you will see a small cylindrical metal, this is the thermocouple.

For gas-powered water heaters, the thermocouple serves as a safety device to detect if the pilot light is burning. When the pilot goes out, this component send a signal to the gas valve to make sure that it remains closed while the pilot light is not yet lit.

This means that if the thermocouple goes bad, there is no way of detecting if the pilot light is burning or not. And when the pilot light goes out, you will not have hot water supply in your plumbing system. To test if the problem is with the thermocouple, try to relight the pilot. If it goes out when you release the button, then the component has worn out.

It is not necessary to remove the burner assembly in order to replace the thermocouple. Professionals can repair the component easily, but, if the burner assembly is removed, it becomes easier to clean out the burner compartment and the burner as well.

If you need to buy a replacement, just head on down to your local home center or hardware store. Before you zip out the door, make sure that you measure the old thermocouple to make sure you get the right sized replacement.

Disconnecting the Thermocouple

Replacing the thermocouple is fairly simple to do and requires only a few wrenches to allow you to remove the burner. A screwdriver will allow you to remove the access cover. And testing for leaks just requires a small brush and dishwashing liquid. However, unless you are capable of doing this, it is better to call for professional help.

Disconnecting the thermocouple would require turning off the gas supply to the unit and turning the temperature valve off. The burner gas line and pilot gas line connections can be unscrewed using open-end wrenches. This allows you to pull down the gas tubes as well as the thermocouple from the gas valve. The burner can be slid out of the unit after disengaging the tab holding it in place.

Replacing the Thermocouple

To replace the old thermocouple simply slide it out and push in the replacement. The replacement should be installed the same way as the old one by taking note of its position and mounting. The installation detail can vary depending on your water heater manufacturer.

The burner can be reinstalled after that by pushing its ends. The thermocouple and pilot tubes should go into the gas valve. The nuts should be hand tightened to ensure that the threads are not stripped. Use the wrench with moderate pressure to completely tighten the nuts.

Testing for Leaks

It is important to make sure that there are no leaks on your water heater after you replace the thermocouple. Open the gas supply to the unit and light the pilot. Reinstall the access covers and slowly turn up the temperature until the burner is lit.

Use the dishwashing liquid solution to check the connections around the pilot light and burner. Make sure that the burner is turned on when you do this test. When you see bubbles, shutoff the gas immediately and tighten the fittings further. If you still detect a leak after doing this, it is time to call a professional service.

As simple as it may sound, you can encounter some problems when replacing the thermocouple. So your safest bet in fixing it properly is to call Scott English Plumbing so that your water heater can be checked thoroughly and request for a water heater replacement.