AO Smith Tankless Water Heater Stuck In Standby Mode

AO Smith Tankless Water Heater Stuck In Standby Mode [Solved!]

AO Smith Tankless Water Heater is stuck in standby mode if you use excessive amounts of hot water in a day or the water temperature exceeds the safety level. 

Resetting your water heater will be a simple step to get your water heater out of standby mode. And this guide will show how you can deactivate the standby mode and bring your water heater to the normal operating state. 

Without further ado, let’s dive in. 

Table of Contents

Why Does My AO Smith Tankless Water Heater Stuck In Standby Mode?

Your AO Smith Tankless Water Heater will get into standby mode for several reasons. If you use too much hot water, it may get stuck in standby mode. Sometimes, the excessive water temperature can also activate the standby mode. 

Like every water heater, AO Smith Tankless Water Heater has also a safety feature called ECO or electric cut-off switch. If it senses the water temperature exceeds the safety level or goes above 180-degree F., it will turn the electric supply off. Consequently, the heating element won’t heat the water and your water heater goes into standby mode. 

And when the standby mode gets activated, the water heater doesn’t function at all. You can easily get your water heater out of standby mode by resetting it. In the next chapter, I will show you how to reset your AO Smith Tankless Water Heater. 

How To Reset AN AO Smith Tankless Water Heater?

It’s not rocket science to reset an AO Smith Electric Tankless Water Heater. Just go along with the following steps to reset your water heater: 

  • Ensure you disconnect your water heater from electricity by flipping down the circuit breaker. 
  • Use a screwdriver to unscrew the nuts that hold the upper access panel. 
  • Remove the access panel and pull out the insulation as well.
  • Now, you can see a round red button. It’s known as a reset button or electric cut-off switch. Just press the button inward and you can hear a click. 
  • It will reset your heater. Finally, put the insulation and the access panel back into their places. 
  • Bring back the electric supply to your water heater and turn on your water heater to verify your unit is running properly.


Why is my tankless water heater not turning on?

Your tankless water heater is not turning on if the unit receives no electric power. Besides, non-functioning upper thermostats, tripped limit switches, and burn-out heating elements are also responsible for this issue.

What's the lifespan of a tankless water heater?

A tankless water heater will last up to 15-20 years if you maintain it properly.

Should a tankless water heater be serviced?

Yes, a tankless water heater should be serviced periodically or monthly. The good news is- you don’t need to maintain a tankless water heater more often than the tank water heater requires. What you need to do is- just check the electrical or gas components and take the necessary steps if you find any issues.

How often should a tankless water heater be flushed?

You should flush a tankless water heater at least once a year. However, it’s advisable to flush the tankless water heater every six months.

Can you use vinegar to clean the tankless water heater?

Yes, you can use vinegar to clean a tankless water heater undoubtedly as it doesn’t bring any damage to your heater components. Instead, it will cut the calcium and deposit buildups.


It’s quite easy to deactivate the standby mode of your water heater. Just follow the step-by-step guide I mentioned above to reset the water heater. And it will bring your water heater back into normal operating conditions. Best of luck!

Read Also: 

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *