Rinnai Tankless Water Heater No Power

Rinnai Tankless Water Heater No Power [3 Easy Solutions]

Your Rinnai Tankless Water Heater will get no power due to a tripped GFCI outlet, faulty electric outlet you use to plug the unit, and bad PC board. 

If you want to restore electric power to the unit, you must fix those issues. And this guide will walk you through the troubleshooting step to solve those problems. So, stay in tune with me till the end. 

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Rinnai Tankless Water Heater No Power [3 Easy Solutions]

These three culprits are responsible for your Rinnai tankless water heater to get no electric power: 

01. GFCI Outlet Gets Tripped

A GFCI outlet is a safety feature. It cuts the electricity if there occurs any short and protects your electric appliances. If the GFCI gets tripped, no power will flow to your electric devices, including your water heater. That’s why you will get no power to your Rinnai Tankless Water Heater if the GFCI outlet gets tripped. 

How To Fix: 

Resetting the tripped GFCI outlet will be a simple fix to this issue. Just locate the GFCI outlet box in your house and press the reset button on the GFCI outlet. I am pretty sure it will turn the electric power back to your Rinnai water heater. 

02. Electric Outlet You Use To Plug The Unit Gets Faulty

A faulty electric outlet that you use to plug your tankless water heater can also be the culprit behind the no-power issue. If that outlet gets defective, you won’t get sufficient electric supply to power on your water heater. 

How To Fix: 

You can easily determine whether the electric outlet is at fault or not. Just unplug your water heater from that specific outlet and connect other appliances like your smartphone charger. If it’s not charging your phone, the electric outlet is at fault. I recommend you call a certified electrician to fix this outlet issue. 

Besides, ensure you plug the unit into a properly grounded, 120VAC electric outlet. Otherwise, the unit will not get sufficient electric supply to turn on. 

03. Fried PC Board

A defective PC or controller board is the main culprit that causes your tankless water heater to get no power. The controller board gets fried out due to power surge or outage, electrically shorted wiring inside the board, and loose wiring.  

How To Fix: 

Before replacing the PC board, test it electrically first. Regarding this, disconnect every wiring from the controller except the wire comes from the secondary side of the transformer. If you don’t get any power at the terminals running to the wall-mounted controller, understand the PC board is at fault. 

So, what you need to do next is- pull out the old PC board from the unit by disconnecting all the wiring. Then, install a new controller board and set it to the same setting of the Dip switch. Of course, it’s not a bad idea if you call a certified technician if you are not comfortable with it. 

Rinnai Tankless Water Heater No Hot Water After Power Outage

If you experience a power outage, the tankless water heater won’t run. Power outages cause several electric issues like tripping the circuit breaker, burning the wires, and making the electric outlet problematic. 

All of these issues prevent the electric power from flowing to the unit. Without power, you can’t turn on the unit. As a result, the water heater will no longer heat the water. 

After a power outage, I highly suggest you check the circuit breaker for the trip and the wiring harness of the unit. Solve the issues if you find one to let the unit get sufficient electric supply for powering on. 

Either way, you can use the Hugo X-1 Battery Backup system to run your Rinnai tankless water heater to get hot water during the power outage period. 


What happens if tankless water heater loses power?

You can’t turn on and operate the unit if the tankless water heater loses its power. Consequently, you will get no hot water from the unit. Just restore the power to the unit if you want to run the water heater.

Does a tankless hot water heater work if power goes out?

No, a tankless hot water heater doesn’t work if power goes out. Without electric power, the control panel of the unit will not work anymore. Needless to say that the control panel is the heart of the tankless water heater. If the heart doesn’t work, how can you operate the hot water heater?

Do tankless gas water heaters have a battery backup?

No, tankless gas water heaters don’t have a battery backup as the control panel is powered by electricity.

Does Rinnai have pilot lights?

No, the Rinnai water heater doesn’t come with a pilot light. It has an electric ignition device that ignites the burner automatically.


Electric issues like tripped GFCI, faulty outlet, defective circuit breaker, and burnout PC bad are the culprits that cause the Rinnai tankless water heater to get no power. Fortunately, I discussed the solutions to those issues. So, just follow the troubleshooting instructions I mentioned and fix the no-power problem.

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