Having your water heater repeatedly turn itself off can be frustrating and inconvenient. You may have no hot water for showers, dishes, or laundry. But why does this keep happening? Why does my water heater keep turning off?
Thermostat issues, pilot light or igniter problems, insufficient venting, and sediment buildup are common reasons a water heater turns off. Temperature and pressure relief valve leaks, insulation and standby losses, and electrical Issues can also cause your water heater to shut off unexpectedly.
Let’s explore each of these issues in more detail:
Reasons Why Water Heater Keep Turning Off
Thermostat Issues
A faulty thermostat is one of the most common culprits for a water heater turning off. The thermostat is the component that controls the temperature of the water and turns the water heater on and off to maintain the set temperature.
Over time, thermostats can fail or become inaccurate, causing the water heater to cycle on and off more frequently as it tries to maintain the correct temperature. Therefore, the thermostat is usually the first thing to check if your water heater keeps cycling on and off.
To test the thermostat, feel the top of the water heater where the thermostat is located. It should feel warm but not overly hot when the water is heating. If it feels very hot or cold when it should be heating, the thermostat is likely bad and needs replacement. Thermostats typically only cost $15-30 to replace and are easy for most homeowners to do themselves.
Pilot Light or Igniter Problems
For gas water heaters, issues with the pilot light or igniter can cause intermittent heating problems. The pilot light is the small, constant flame that stays lit to ignite the main burner. It can go out occasionally due to drafts or low gas pressure. The igniter is an electric component that sparks to light the pilot on an electric ignition model.
The water heater cannot stay lit if the pilot light keeps going out or the igniter fails. Inspect the pilot and igniter for signs of damage, corrosion, or debris blocking the flame. Clean or replace as needed. You may also need to adjust the thermopile if the pilot has trouble staying lit.
Temperature and Pressure Relief Valve Leaks
A leaking temperature and pressure relief valve (TPR valve) can cause the water heater to keep turning off as a safety measure. This pressure relief valve is designed to discharge hot water if the pressure or temperature in the tank gets too high.
If it leaks continuously, even in small amounts, it will lower the pressure in the tank and trip the high-pressure cutoff switch to turn the burner off. Inspect the valve for corrosion, mineral buildup, or physical damage. Replace it if necessary to re-establish the proper pressure.
Sediment Buildup
Over years of use, mineral deposits from hard water can accumulate at the bottom of the tank. Heavy sediment reduces the water heater’s storage capacity and insulating properties. It also causes the heating element or burner to work harder and cycle on more often.
Draining sediment reduces excess cycling. Most water heaters should be flushed every six months, depending on the water’s hardness. Turn off the gas supply, attach a hose to the drain valve, and open it to flush deposits from the bottom.
You may need to clean heavily scaled tanks chemically. A water softener can also help reduce sediment buildup. To prevent future sediment issues, periodically check the tank and flush it as needed.
Insufficient Venting
Inadequate combustion air venting can also cause intermittent heating issues. Gas water heaters need airflow into the room for proper combustion. Clogged, blocked, or undersized vent piping restricts oxygen flow. The flame may keep going out, triggering the unit to shut off.
Check that vent piping is intact, secured correctly, and meets code specifications. Clean out any debris or re-route venting as needed if it appears constricted. Proper vent sizing is important for dependable water heater function.
Insulation and Standby Losses
On electric water heaters especially, inadequate insulation or standby heat losses can cause the heating element to cycle on and off, frequently trying to keep up with heat loss. Over time, this excessive cycling can shorten the life of heating elements.
Check the insulation wrap for any tears, gaps, or signs of deterioration. Replace if needed. Adding additional insulation may help reduce cycling for older, less efficient models. Ensure the water heater is also located in an uncooled space, like a garage, rather than inside living areas.
Electrical Issues
In rare cases, problems with the electrical supply, like loose wires, corrosion, or inadequate power, could trip limit switches and safety devices. This will make your water heater keep turning off.
Check that the water heater is plugged into the proper circuit and receptacle. Have an electrician inspect for any electrical faults if cycling persists after addressing other common issues.
Other Potential Issues Causing Water Heaters to Keep Turning Off
Beyond these common issues, there are a few other things that could cause an intermittent water heater:
- Damaged elements or heat exchanger
- Low gas pressure (for gas models)
- Faulty gas control valve or regulator
- Damaged dip tube (cold water inlet)
If you have eliminated the above issues and are still experiencing frequent cycling, it’s best to call a professional plumber for further diagnosis and repair. A licensed plumber will have the knowledge and tools to troubleshoot and fix any underlying problems with your water heater.
Water Heater Maintenance Tips
Maintaining your water heater properly is essential to prevent future cycling issues. This includes flushing the tank regularly, checking and replacing faulty components, and ensuring proper insulation and venting.
Additionally, here are some maintenance tips to keep your water heater running smoothly:
- Check the pressure and temperature relief valve annually to ensure it functions correctly.
- Inspect the anode rod every few years and replace it if necessary to prevent corrosion in the tank.
- Set your water heater’s thermostat to 120°F for optimal energy efficiency and safety.
- Regularly check for leaks or signs of corrosion on the tank, pipes, and fittings.
- Drain the tank completely if you will be away from home for an extended period.
By following these maintenance tips and addressing any issues promptly, you can help extend the lifespan of your water heater and keep it running efficiently. Always consult a professional plumber for repairs or replacements beyond basic water heater maintenance tasks.
Why Does My Water Heater Keep Turning Off? Final Thoughts
Intermittent water heating problems can be frustrating, but proper maintenance and troubleshooting can often be resolved. It’s essential to regularly check for common issues like faulty pilot light or TPR valve leaks and address them promptly.
Additionally, maintaining your water heater properly and seeking professional help when needed can help prevent future problems and extend the life of your unit. So, if you are facing intermittent water heating issues, don’t panic. Follow the tips mentioned above to keep your water heater functioning efficiently.
