Gas Hot Water Heater Thermocouple Troubleshooting

Common problems and how to fix them.

Gas hot water heater thermocouple troubleshooting.

When the thermocouple does not sense flame it prevents the gas valve from delivering gas to the burner. 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 diagnose and repair a faulty atmospherically vented gas fired water heater. A general troubleshooting discussion is provide in the article identifying and repairing water heater problems.

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. Example tank is a john wood 40 gallo. The thermoucouple is a simple replaceable part on your hot water heater. Troubleshooting a water heater thermocouple.

You will not have hot water supply in your plumbing system. Building mechanical systems oil gas heating water heaters gas burner flame safety water mild chemicals gases dry areas engines hospitals food industry. A thermocouple or flame sensor is a device used to control gas flow in gas water heaters on older style heaters with standing pilot lights the device is typically called a thermocouple while on newer units with electronic ignition the same or virtually the same device is called a flame sensor for our purposes we ll refer to both devices as the thermocouple. Gas hot water heater troubleshooting guide will assume that the gas unit was correctly sized professionally installed per codes and manufacturers.

There are no adjustments or parts that can be repaired or replaced. Type k chromel alumel are the most widely used general purpose thermocouple 200 c to 1350 c 330 f to 2460 f. The thermocouple found in older water heaters that have permanently lit pilot lights or the flame sensor found in newer water heaters is a simple device that senses the heat in the pilot light flame. For gas powered water heaters the thermocouple serves as a safety device to detect if the pilot light is burning.

The danger with a gas hot water heater is the gas itself. 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. Troubleshooting low performance insufficient hot water pilot light problems improper gas combustion issues with the pilot light thermocouple gas burner venting and other common issues. If it is not behaving as it should replacing it is the only option.

To test if the problem. 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.