Why Does the Gas Water Heater Keep Turning on and Off?

It is perfectly normal for a gas water heater to turn on and off every day. However, if the thermocouple is dirty, damaged or bent, the pilot tube is dirty, the air valve is faulty, or the air inlet is blocked, the unit may shut down prematurely. A stuck flow switch will cause the tankless unit to open more often than necessary.

Usually, the water heater doesn't actually turn off. While some devices may actually only be on for about 5-6 hours a day, that doesn't mean they're off the rest of the time.

When you are not using hot water, the appliance remains in standby mode. This fact ensures that you have hot water whenever you need it.

If you're going on vacation, you can turn off the water heater manually. For example, there are also special timers that allow the device to turn on an hour before you wake up.

The unit will only operate when someone is actually using the hot water. After that, the water heater will automatically turn off - you don't need to turn off the unit manually.

Once the device turns itself off, it goes into standby mode. While some models with a tank will continue to maintain the water temperature, tankless water heaters do not use electricity to maintain the water temperature. 

However, they are not completely closed, as these units always have components responsible for sensing the flow of water to operate.

If you are able to light the pilot but it keeps going out, it may be a problem with the thermocouple.

Dirty, bent, or damaged components will not sense pilot flames. Therefore, the thermocouple will not keep the air supply on. In this case, you may need to replace the thermocouple.

If the pilot tube is clogged or dirty, the light may not illuminate at all or be very faint. A flickering yellow flame is the most obvious sign of dirty pilot tubes and burners.

The gas is transferred into the device through the gas valve. If the gas supply is interrupted by a valve failure, the water heater will shut off.

Your gas water heater may have an air intake screen on the bottom. These screens can become clogged with dust, hair, pet dander, etc.

All gas burners require a constant supply of air to function. If the intake port is dirty, there may not be enough airflow to keep the burner running.

A gas water heater with a tank will cycle on and off several times a day as it needs to keep the water in the tank hot.

Fact: The water in the tank constantly loses some heat from the walls and from the exhaust.

This could be caused by……

Bent, damaged, or dirty thermocouple

The gas valve is broken

Dirty pilot pipe or burner

Dirty or clogged air inlets

The water heater isn't really shutting off completely - even if the unit isn't producing hot water at the moment, it's always ready to start running.

On average, a water heater runs about 3 hours a day (meaning the unit will actually produce hot water and deliver it to your faucets and appliances during this time). The total run time of a tankless water heater is usually short - about 1-2 hours.

If your gas water heater is off, it's a good idea to call in a professional to deal with the problem. There is a high chance of a problem with the gas supply, burner, or thermocouple, and any problems with these components are usually not easy to DIY fix.

1. Dirty Squibs - Squibs are the components that supply gas to the indicator light. If the tube is partially or completely blocked, the light will not stay on.

2. Dirty Thermocouple - If the thermocouple does not sense the pilot flame, it will close the gas valve. Dirty elements may not feel the fire at all.

3. Bent Thermocouple - The element must be next to the indicator light, otherwise, it will not receive the necessary heat. This is exactly what happens if the thermocouple is bent.

4. Faulty Thermocouple - The component may just be faulty. In this case, all you can do is replace the thermocouple. 

5. Hose Problem - This long tube connects the burner to the gas controller. If it is clogged or damaged, it will not be able to supply air to the water heater.

6. Main Control Valve Failure - This is a very rare problem, but at some point, the components responsible for regulating the water pressure and gas pressure of the equipment may fail. In this case, the gas valve will be closed.

Signs of a malfunctioning thermostat include:

No or insufficient hot water

Constantly tripping the upper limit switch

Slow recovery of hot water

The water is too hot

Of all these issues, the trip limit switch is the only thing that will keep your water heater off.

The above details the reasons why the gas water heater keeps turning on and off and how to deal with it. If you want to buy a new gas water heater, please contact us.

Greaidea is a professional custom gas water heater manufacturer with over 20 years of experience. In our R&D department, 12 engineers are employed to guarantee our R&D advantage and innovation advantage. The test room and assembly line have been upgraded. Spend 3% of revenue on research and development each year. Has an excellent manufacturing team and QC team, with an annual output of 500,000 sets of gas water heaters, and first-class quality.