AO Smith Water Heater Too Hot

AO Smith Water Heater Too Hot [How To Fix]

This is a complete guide on AO Smith Water Heater Too Hot. Here what I am going to break down: 

  • 3 common reasons that cause electric water heaters to get too hot.
  • What troubleshooting steps you should take to fix those 3 water heater problems
  • And a lot

Without further ado, let’s dive in. 

Table of Contents

AO Smith Water Heater Too Hot [3 Easy Solutions]

Your AO Smith Water Heater will get too hot due to a malfunctioning thermostat, a faulty or electrically shorted heating element, and setting the thermostat too high. If you want to fix the hot water issue, you must address and solve these problems. 

Below, I will break down everything that causes the water heater to overheat the water. So, stay in tune till the end. 

01. A Malfunctioning Thermostat

A malfunctioning thermostat

A common water heater problem that can throw a wrench into the work is a non-functioning thermostat. If you have an AO Smith Electric Water Heater, the thermostat is the first element you should check if you get too hot water. 

A malfunctioning thermostat means the temperature of your water heater won’t be set at the appropriate level. Consequently, you will get excessive hot water out of the unit. 

You can easily determine whether the thermostat is at fault or not. Just measure the water temperature from the nearest faucet. If the temperature of the water exceeds the selected thermostat setting, understand the thermostat is the culprit. 

How To Fix: 

Before jumping the gun on replacing the thermostat, inspect it electrically to ensure it’s the problem. So, get a multimeter. Then, turn the electric supply off to the unit. Second, remove the upper access panel and fold away the insulation. 

Next, remove the protective cover. Now, follow the steps mentioned in the following tutorial to check the thermostat: 

If you get no continuity, you must replace the thermostat. Just detach the wires from the thermostat and slide the thermostat up and remove it. Then, install a new thermostat and connect the wiring with it following the wiring diagram. 

02. Heating Element Gets Electrically Shorted

Defective heating element

Your AO Smith Electric Water Heater will overheat the water drastically if the heating element gets electrically shorted. 

Now, the question may pop up in your mind- how can I understand when the heating element gets electrically shorted? If the T&P valve of your water heater releases a large amount of hot water, know it’s due to a shorted heating element. 

However, checking the heating elements electrically is the best way to determine whether the heating element is at fault or not. 

To test this water heater component electrically, turn the power off at the circuit breaker. Then, use a flat head screwdriver and remove the upper access panel. Next, remove the insulation to access the heating element. 

Now, get a multimeter and set its leads between the two screw terminals on the upper heating element. A healthy heating element should give a reading between 5 to 25 Ohms. If the resistance of the part goes out of range, I bet the heating element gets bad. 

How To Fix: 

Replacing the heating element that gets electrically shorted or defective is a must. And the best part is- you can do this replacement work by yourself. Go along with the following steps to change the defective heating element:  

  • Turn the electric supply off at the circuit breaker. 
  • Open a hot water faucet and allow it to run until the unit is cool. 
  • Attach a garden hose to the drain valve at the bottom of the unit and place the other end of hose to the nearest drain floor. 
  • Once you drain all the water from the tank, remove the upper or the lower access panel. 
  • Pull out the insulation and access the heating element. 
  • Remove the power wires from the heating element. 
  • Remove the bad heating element with the help of an element wrench. 
  • Use a rag and clean the threads in the tank opening. 
  • Now, install a new heating element and tighten it up. 
  • Fill the water tank by opening the cold water supply valve. 
  • Inspect the newly installed heating element for a leak. 
  • If there is no leak and the tank is full, attach the power wires to the heating element. Then, replace everything like the insulation and access panels.
  • Finally, turn the power back to your water heater. 

03. You May Set The Thermostat Too High

The water temperature will get too high if you set the thermostat on your AO Smith Water heater at the high setting. Luckily, you can easily solve this problem by adjusting the thermostat on the unit.  

How To Fix: 

Go with the following steps to adjust thermostat on your AO Smith Water Heater: 

  • Ensure the electric power to the unit is turned off. 
  • Remove both the upper and the lower access panels and fold away the insulations. 
  • Now, turn the water temperature dial on the thermostat clockwise to increase or rotate the dial counter-clockwise to decrease the temperature. Make sure you set both the temperature dials at the same temperature settings. 
  • Once you set the thermostats according to desired temperature settings, replace both insulations and access panels. 
  • Turn the electric power back to the water heater. 
  • Wait for the water to heat up. 

You May Also Find Interesting: AO Smith Water Heater Temperature Adjustment


What do I do if my hot water is too hot?

You should first figure out what causes the water heater to get excessively hot. Then, fix those issues to bring your water heater back to normal condition. 

Generally, a non-functioning thermostat, shorted heating element, and setting the thermostat too high are some common reasons behind an overheating water heater. 

Luckily, I mentioned every troubleshooting step you should take to fix the issue. So, follow the steps I recommended.

How long should a hot water thermostat last?

A hot water thermostat will last up to 8 to 10 years if you maintain the unit according to the manual.

How do I reset my water heater thermostat?

Resetting the water heater will automatically reset the thermostat as well. Just remove the upper access panel of your electric water heater. Then, locate the red reset button by removing the insulation. Now, press the red button and it will reset both the unit and the thermostat setting.


Excessive hot water is a common problem every homeowner encounters. If the water temperature gets too hot, it will burn the skin. Turns out, overheated water can also damage the unit. 

Luckily, this guide on AO Smith Water Heater Too Hot disclosed everything behind the issue. Plus, I also broke down the troubleshooting steps you should follow to fix the hot water issue. So, follow our guideline and I hope it will solve your water heater problem. 

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