Gas Water Heater Thermocouple Test

Anything under or hovering around the 20 millivolts mark means the thermocouple needs to be replaced.

Gas water heater thermocouple test.

The gas water heater thermocouple is the safety element that is designed to inform a gas control valve is the pilot flame on or off and open or close the gas to the main burner. How to test a thermocouple for a water heater everyone who has owned a gas heater including furnaces or water heaters will know that from to time you have to light the pilot light unless you have the electronic ignition that automatically lights the pilot light. If the thermocouple is working you should be able to measure 30 to 40 millivolts of voltage at the connection end of the tube when the pilot flame is on. You know you have a problem.

How to test a thermocouple with a multimeter. Take the thermocouple to the store and replace if needed. Turn off the gas to the water heater and remove the thermocouple from the water heater. Sometimes when you try to light the pilot it does not want to stay lit.

When it stops working the furnace s pilot light also turns off. The thermocouple will be located right next to the pilot. Right next to the pilot light is a small metallic tube known as a thermocouple. Thermocouples designed for residential gas appliances such as fireplaces water heaters and furnaces are made for 30 millivolts.

This is a safety device whose purpose is to monitor the pilot light and send a signal that shuts the gas burner valve should the pilot. Importantly always make sure the tip of the thermocouple is directly in the pilot flame. If you test the thermocouple with the multimeter and you get a reading above 25 then you have another issue. The thermocouple is part of the pilot assembly where one end is always in contact with the pilot flame while the other side is connected to the gas control valve.

For a basic test attempt to turn on the pilot light. First shut off the gas valve on the water heater and the gas valve on the gas line near the heater. Then unfasten the three nuts that hold the thermocouple and the two gas tubes to the valve. The reading should be between 25 and 30.

How to test a thermocouple. Inside your gas operated water heater is a tiny gas flame called a pilot light whose purpose is to ignite the burner whenever the temperature falls below the thermostat setting. A gas water heater in boise baton rouge buffalo or boston uses a thermocouple that includes a probe attached to a copper tube that screws into a port on the gas valve. Install the new thermocouple turn on the gas and light the pilot.