Water heater won’t heat? Here’s why & how to fix it fast!

Dealing with a water heater that won’t heat can be frustrating, especially when it leads to cold showers and hands. Thankfully you can do a little investigative troubleshooting to find out what’s going wrong so you can fix it yourself!

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Common reasons why your water heater won’t heat & DIY fixes

Here are some of the top reasons that prevent a water heater from heating & what you can do about them.

Important: The following information may not apply to your specific appliance model. While we strive to offer helpful advice for DIY appliance repairs, variations in models and configurations can lead to differences in troubleshooting steps, error codes and part replacements. For the most accurate guidance, we strongly recommend consulting the technical sheet for your specific appliance model.

1. The pilot won’t light (gas models)

One of the most frequent culprits behind a gas water heater not heating is a pilot light that won’t stay lit. This issue is often linked to the thermocouple or a dirty burner.

Solution:

• Check the thermocouple, which senses when the pilot is on. If it’s dirty or out of alignment, it may stop gas flow, which can prevent the pilot light from lighting. You may need to clean it or adjust its position.
• Clean the burner by using a soft brush to remove any debris that may be clogging it.

2. Electronic ignition system won’t light (gas models)

If your water heater uses an electronic ignition system and it’s not working, this can prevent the water heater from heating. Electronic ignition issues are often related to power problems or faulty parts.

Solution:

• Make sure the water heater is connected to a power source and the circuit breaker hasn’t tripped.
• Inspect the ignition system to see if the power supply is working by testing it with a multimeter.

3. Gas supply issues (gas models)

If the pilot won’t light on the water heater, or if it’s going out frequently, check the gas flow.

Solution:

• Check the gas valve: Make sure the gas valve is open and supplying gas to the water heater. You can check this by mixing a teaspoon of dish soap with one cup of water and spraying it on the valve. If there are bubbles, that means there’s a leak.
• Call a professional: If there’s a gas supply issue, you’ll need to have a licensed professional inspect the gas line before you use it.

4. Heating element failure (electric models)

For electric water heaters, a common issue is a burned-out heating element. If the heating element is defective, your water heater won’t heat, even if it seems to be functioning otherwise. Keep in mind that some electric water heaters have more than one element. 

Solution:

• Test the heating element(s): Use a multimeter to test if the heating elements are working. If an element is faulty, you’ll need to replace it.
• Test the thermostat: If the heating element is functioning, the thermostat might be malfunctioning and will need replacement.

5. Faulty thermostat

A broken thermostat can lead to inconsistent water heating, with water either being too hot or not hot enough. This issue can occur in both gas and electric water heaters.

Solution:

• Reset the thermostat by pressing the reset button (if your unit has one).
• Test the thermostat for continuity with a multimeter

If the reset doesn’t work or if the thermostat fails the continuity test, you’ll need to replace it.

6. Sediment buildup

If your water heater has been in use for some time or if you have hard water, sediment from hard water can accumulate at the bottom of the tank. 

Solution: Flush the tank at least once a year or more if necessary to remove sediment buildup and improve the performance of your unit.

7. Broken dip tube

The dip tube directs cold water to the bottom of the water heater’s tank where it can be heated. If the dip tube is broken, cold water will mix with hot water, which can result in lukewarm temperatures.

Solution: Replace the damaged dip tube with a new one.

Frequently asked questions

Get answers to some of the most common water heater questions.

Why won’t my water heater light?

This can be caused by several reasons. In gas water heaters, there may be a faulty thermocouple, which may not detect the pilot flame. A clogged burner or problems with the gas supply can also cause this problem. In electric water heaters, a power failure or a malfunctioning ignition system could be the culprit.

What do I do if my electric water heater won’t light?

When your electric water heater won’t light, the first thing you should check is the power supply. Make sure the water heater is plugged in and the circuit breaker hasn’t tripped. If the power supply is good, you’ll need to check the ignition system for any faulty parts.

Can a dirty burner prevent my water heater pilot from lighting?

Yes, a dirty burner can block the pilot light from lighting properly. Debris buildup on the burner can prevent gas flow, which leads to ignition problems. Cleaning the burner regularly helps prevent this issue and keeps a consistent flame for the pilot light.

Why does my gas water heater pilot light keep going out?

A gas water heater pilot light may keep going out due to a faulty thermocouple, insufficient gas pressure, or a draft blowing out the flame. Start by inspecting and cleaning the thermocouple and making sure it’s positioned correctly. Then check for gas pressure problems or possible drafts near the water heater.

More for you

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