Gas Water Heater Thermocouple Test

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.

Gas water heater thermocouple test. The thermocouple is a vital safety feature for many gas appliances. How to test a thermocouple. The water heater thermocouple is a device that monitors temperatures in the water heater to determine whether it needs to heat up or turn off the heat. A thermocouple is a safety device that helps control the gas supply in gas heated furnaces.

For a basic test attempt to turn on the pilot light again. Once it is removed you will need a multimeter that needs to have the ability to read millivolts and a source of fire. With the leads apart you will read infinity. It is comprised of two different types of metal which react differently to heat and expand at different rates signaling to the water heater when to turn on or off.

First remove the thermocouple. Use a small flame source to test a thermocouple with a multimeter. Multimeter thermocouple test procedure. Then unfasten the three nuts that hold the thermocouple and the two gas tubes to the valve.

You can test this yourself using a multimeter but you may need a helper to keep the pilot flame burning while you do it. Gas appliance thermocouples have a standard design. 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. If you re still unsure or don t have a working pilot light test the thermocouple with a multimeter.

Finally now turn the meter to volts. If you can t light the pilot the problem most likely lies with the gas control valve or the gas flow itself not the thermocouple. Usually a lighter will suffice for the test. Light the pilot by pressing and holding the pilot light button on the gas control valve.

That is simply a test to check the meter for continuity. Here s how to test a suspected thermocouple in a gas operated water heater. Secondly turn on the meter and set it to ohms. One probe of the meter should be connected to the copper sheath of the thermocouple and the other to the gas valve.

Touch the two leads together from the meter and you should get a reading close to zero. Diy hot water heater repair. When it stops working the furnace s pilot light also turns off. First shut off the gas valve on the water heater and the gas valve on the gas line near the heater.

For testing a thermocouple you first have to remove it from the furnace water heater or gas appliance where it is installed. The burner typically sits loosely or under clips in the burning chamber and just slides out.