What Causes The Pilot Light To Go Out On A Hot Water Heater
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The pilot light on a water heater can go out now and then on its own for no particular reason. Pilot lights are designed to work continuously, however, so your pilot light will not keep going out unless you have some sort of mechanical problem. Unfortunately, there are a number of things that could go wrong with a pilot light, and some of them get...
M/F A pilot light is a somewhat outdated way to light a water heater or any other gas burner. A small flame is kept burning all the time. When the water heater needs to turn on, this flame lights a jet of gas on fire, which heats up the water through a heat exchanger. Because pilot lights constantly burn gas even when they are off, modern systems use an electronic ignition system instead.
M/F The thermocouple is at the heart of the circuit that controls the pilot light, and is the most common part to fail. If the pilot light blows out and the gas keeps flowing, it creates a hazard. The gas can build up, causing a fire or asphyxiation. The thermocouple detects the heat from the flame of the pilot light. When the thermocouple is heated, it produces an electric current, which tells the circuit that the pilot light is on. If the thermocouple stops producing this current, the heater knows that the pilot light is off and closes the valve, stopping the gas from flowing.
M/F The thermocouple can malfunction in several ways. Like other electronic equipment, a thermocouple can simply age and burn out. The contacts connecting the thermocouple to the rest of the circuit can also become corroded, preventing current from flowing through. If the thermocouple is not correctly situated, it will also not work properly. The thermocouple bulb has to be directly above the flame, or else it will not register that the pilot is on, and turn it off.
Gas Flow Problems
M/F The pilot light is a flame, and a flame needs the right air supply to keep burning. Oxygen needs to continuously move in and combusted gasses need to flow away from the flame or else they will snuff the flame. If the water heater is in a confined space, there might not be enough airflow to keep the pilot light burning. On the other hand, sudden drafts can blow out the pilot light just like a candle. One of the most serious problems is obstructed exhaust flow. If the chimney is blocked by a bird's nest or soot buildup, the burnt gasses can not flow out. They will build up and extinguish the pilot light.
M/F The gas valve can also cause the pilot light to go out. The gas valve controls the flow of gas into the pilot. If it gets jammed or obstructed, it can stop the gas from flowing in fast enough to keep the pilot light going. It can also cause the gas to come in spurts and sputters, which can also disturb the pilot light.