Thermopile Troubleshooting Tips

2 min read

Firstly, you have to know what the thermopile is – it is the electronic device that transform the heat energy turns into electrical energy. This device also includes some thermocouples in series or parallel arrangements.

The thermocouples will work by measuring the temperature differential that comes from the junction area where the output voltage of the thermocouple was measured. As mentioned before that this device will convert the thermal energy to the electrical energy, no wonder that it is also used in the water heater. Sometimes, people ask around thermopile voltage low on water heater. 

How thermocouples work

You have to know that the pilot lights will heat the thermopile and thermocouple which produce the small millivolt of electricity that moves to the gas control valve. You should know that the currents from the thermocouple will control the pillow tube in the hollow copper with the wires inside.

The currents from that travel will go through two cables that passing tco then moves to the gas control. If you find that the light just off, the less power supply will cause shutting down all the gas to your water heater. The ordinary function will be restored after the pilot light turns on back.

The old model of water heater needs a bit more adjustments and patience to light up the pilot, while the newer water heater machines have sealed the combustion area and using that spark which made by the special device to re-light your pilot. 

Thermopile Voltage Low on Water Heater

As mentioned before that there is a special device that can create the spark to relight the pilot. Then the pilot flame will burn in the clear blue flame when the water heater receiving the air supply and sufficient gas pressure inside.

The pilot lights will perform some jobs such as heating the thermocouple or thermopile which creates a small electrical current that gives the power on the gas control operation as well. Then it gives the essential signals to the gas control valve that pilot was turned on and turning the gas when it released down. 

You should know that the thermopile is basically some thermocouples which been united together. The thermopile can cause more currents rather than thermocouples. The thermopile will produce sufficient currents for the power circuit board inside your electronic gas, thus it can complicate the states of heater operation, releasing the error codes through led light status and control the operation. Thermocouples also produce a small current for the mechanical gas valve, but it does not enough for the circuit board on your electronic gas control. 

Honeywell Thermopile Voltage Low Fix

Thermopile Troubleshooting Tips
Thermopile Troubleshooting Tips

Open the open circuit thermopile testing 

You need to follow the instruction lighting labels on your water heater, then you can continue to turn on the pilot and let it operates for around three minutes. If your pilot still cannot lit, then you have to hold the pilot button – spin the gas control knob to the pilot position, and you need to push and hold it – you need to perform this step during the testing.

You can use the multimeter which can measure the millivolts, put one lead in the left side of the wire harness and put the second lead on the right side of the wire harness. If your meter reads 300 millivolts or even higher, then your thermophile is okay. But if it reads under 300 millivolts, then you need to replace that pillow assembled now. 

Try the closed-circuit thermophile test 

You have to release the red and white pilot cables from the gas control. You can use the multimeter which can measure the millivolt, connect one lead to the red wire and second lead to the white wire. Always following the lighting instructions on your heater, then start to turn on the pilot and let the heater operates around three minutes.

It is necessary to hold your gas control knob in the pilot position, repeat this test. If it reads more than 400 millivolts, then it shows you with a good thermophile output for your device. If you see the result is under 400 millivolts, then it shows you with a poor thermopile. 

Thermopile Voltage Low Rheem

You water heater may not work and the gas control valve blinked with the two lights – means that you have voltage thermopile. There are many sources that tell you about thermopile voltage low on water heater.

As an example like video below about Water Heater Pilot Light & Thermopile Troubleshooting :