Water Heater Thermocouple Tester

Measure the current by using the multimeter device set on millivolts.

Water heater thermocouple tester.

Once it is removed you will need a multimeter that needs to have the ability to read millivolts and a source of fire. Acceptable range for most water heat. Discretion should be used if the reading is between 21 and 25. 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.

How to test a thermocouple. Usually a lighter will suffice for the test. To make certain the thermocouple is bad you have to test it. Light the pilot by pressing and holding the pilot light button on the gas control valve.

Thermocouple thermometer 50 300 degree industrial temperature meter j k t e n r s type thermocouple dual channel temperature meter tester lcd backlight 3 9 out of 5 stars 7 22 99 22. Here s how to test a suspected thermocouple in a gas operated water heater. 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. For testing a thermocouple you first have to remove it from the furnace water heater or gas appliance where it is installed.

In the early 1900s honeywell applied it to the safety gas valve. 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 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. Thomas seeback discovered it in 1821.

A faulty thermopile may be at fault. If the pilot light doesn t stay lit check the gas water heater thermocouple by keeping the pilot button depressed. The reading should be between 25 and 30. One probe of the meter should be connected to the copper sheath of the thermocouple and the other to the gas valve.

Anything under or hovering around the 20 millivolts mark means the thermocouple needs to be replaced. 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. How to test a thermopile s voltage using a multimeter. Thermocouples designed for residential gas appliances such as fireplaces water heaters and furnaces are made for 30 millivolts.