A.O. Smith Electric Water Heater Troubleshooting – 6 Ideas to Look at

Water heaters are a typical electrical appliance in our homes, and A.O. Smith is well known in this arena. But just like any other appliances, sometimes they don’t work properly. Now, before running on to the store to buy a new heater, you can think of troubleshooting the heater.

But how to do A.O. Smith electric water heater troubleshooting?

There are many troubleshooting ideas. Replacing thermostats, fixing loose connections where necessary, and flushing properly are some troubleshooting steps. Adding extensions like mixing valves may be needed as well. And somehow, if components are damaged, they will need to be replaced.

We know this little information won’t be enough for you. And for this reason, we’ve kept a whole discussion ahead. So, keep reading to get into more details.

Work Procedure of Electric Water Heaters

At first, cold water from the house plumbing line enters the heater and fills it with water. After setting the temperature, the upper thermostat calls for heating, and it turns on the upper heating element, which heats the water.

Water starts to get warmer and reaches the desired temperature. After that, the bottom thermostat starts working just like the upper one. As a result, the desired temperature is maintained.

The heating is turned off once the temperature has been reached. Hot water flows through the plumbing line when needed for use.

As the hot water exits from the heater, more cold water enters the heater and makes the tank temperature down. As a result, the heater restarts and stays at the set temperature.

6 Ideas For Troubleshooting A.O. Smith Water Heater

Any of the heaters may have some common issues. However, water heater problems are not the same as underground propane tank problems. But you can troubleshoot them if you have some basic knowledge. So, let’s get started to discuss A.O. Smith electric water heater troubleshooting.

1. Leaking or Smelly Water

A loose threaded connection can cause your A.O. Smith water heater to leak. If any weak connections are discovered, carefully tighten them until they are snug and secure. Check for any loose connections in the heater’s relief or drain valve, as well as the thermostat connections.

A foul odor might be caused by a high sulfate or mineral concentration in the incoming water supply. To remedy this, flush the entire water tank on a regular basis.

2. Issues with Pilot Lights

If the pilot light fails to turn the unit on, the main gas supply may be turned off. It’s also possible that a filthy pilot assembly will prevent your pilot burner from keeping lit.

Clean the pilot assembly as per correct instructions to get rid of complications.

Sometimes thermocouple malfunction, disconnected wire, melted insulation, etc., can cause issues with pilot lights. In that case, expert servicing might be needed from professionals.

3. No Water or Not Enough Hot Water

If you are not getting enough hot water from the heater, confirm that the power supply is okay. The main switch might be turned off, or the circuit breaker could be tripped. Also, the fuse might be blown. So, considering this, ensure proper power supply to the heater.

You may also test this by pushing and holding the reset button for a few seconds. The voltage may need to be checked as well. If there’s no hot water even after the voltage is okay, you might need to replace heating elements.

If you see a sudden interruption of hot water, then it may happen that the water usage has exceeded the tank capacity. So, wait a bit for the tank to be full again. 

Also, the tank might be undersized according to your needs. In that case, buying a new tank can be a good option.

When the lower thermostat becomes faulty, the water won’t heat enough. It must be replaced in this situation.

Also, ensure that there are no improper or loose wire connections and that the thermostat is installed correctly.

4. Too Hot Water

A water heater is used for a constant hot water supply to the desired temperature. However, the water can become too hot at times.  And it becomes risky to deal with this excessive hot water.

If the water becomes too hot, check the thermostat and ensure that the right temperature is set. Also, check if the thermostats are correctly installed.

Installing a mixing valve can be a solution to this problem. The mixing valve will keep the water temperature to a safe level constantly while using.

For purchasing mixing valves, you can consider the ones we have listed below. Please have a look.

We hope one of these mixing valves will help your cause.

5. Burned Out Heating Elements

If your water heater is not equipped with dry-fired heating elements, the standard type can burn out very easily. It can occur even if the heating element is only partially submerged. So, make sure that the heating elements are fully submerged in the water.

Not just dry firing, heating elements can also fail due to other reasons sooner or later. In such circumstances, you may need to modify them.

6. Noise Troubleshooting

Minerals from the tank water can form limescale on the heating element. As a result, heated water gets trapped in the scale, forms steam, and makes a hissing sound.

To solve this, flush the heater regularly and perform preventive maintenance. Also, clean the heating elements regularly. Replace them if cleaning doesn’t help.

Low-watt density heating elements with a greater contact area can also be used. This will aid in the effective transfer of heat to water.

So, these were the six troubleshooting ways of AO Smith electric heaters.


Where is the reset button located in the water heater?

The reset button is usually red and close to the thermostat. It might also be buried behind the unit’s removable metal panel—and then under some insulation.

What is the most common problem you’ll face with water heaters?

The most typical form of water heater problem you’ll encounter is leakage.

How much does it cost to replace a water heater thermostat?

The usual cost of a new thermostat is anywhere between $100 and $300. The majority of other repairs are also reasonably priced.


As you can see, A.O. Smith water heater troubleshooting is not always straightforward. So, always be careful while using or trying to fix the heater.

Don’t hesitate to contact any professional if you can’t figure out what to do.

So, that was all about A.O. Smith electric water heater troubleshooting.  Don’t forget to maintain your heater properly.