I get it; water heater problems are not fun, and they usually happen at the most inopportune time. But don’t despair! I’m here to help you troubleshoot and fix your Rinnai tankless water heater control panel.
An electrical outlet issue is the #1 reason the control panel on your Rinnai tankless water heater is not working. This problem can also be caused by blown heater fuses, compromised power supply, thermal fuse issues, or a faulty sensor wiring harness.
In the rest of this post, I will cover troubleshooting and fixing your Rinnai tankless water heater control panel in greater detail. Let’s get right into it.
1. Your Electrical Outlets Are Acting Up
We’ve all been there. You plug something in, and the power goes out. Well, the same can happen with your Rinnai tankless water heater control panel. If the electrical outlets in your home are not working correctly, the control panel on your Rinnai tankless water heater will not work either.
To confirm this, plug something else into the outlet your Rinnai tankless water heater was plugged in. If the other appliance does not work, you probably have an issue with the electrical outlet.
How To Fix
If it turns out that the electrical outlet is not working, the next step is to find out why. More often than not, faulty outlets are caused by issues to do with fuses or circuit breakers. That’s why checking the fuse box, and the circuit breaker should be your first course of action.
Specifically, check whether you have a blown fuse or a tripped circuit breaker. These are the most common issues with fuses and circuit breakers, so it makes sense to check for them first. If neither is the issue, keep troubleshooting for other causes of faulty outlets.
Only check your outlets if you know your way around home power supply systems. If you don’t, you’re better off contacting an electrician to come and take a look at the electrical outlets in your home. You don’t want to risk electrocution or causing more damage.
Blown fuses can also cause the “Rinnai tankless water heater no power to controller” issue. They aren’t a common culprit, but they’re worth looking into.
To check if the fuses are blown, remove your water heater’s access panel, locate them, and test them. You can check your unit’s user manual for instructions on locating the fuses.
Using a multimeter is the easiest way to check whether the fuses are blown. You can also use a simple test light if you don’t have a multimeter.
To test the fuses, set the multimeter to the “ohms” setting. Touch one lead of the multimeter to each of the fuse terminals. If the multimeter or test light beeps or lights up (respectively), the fuse is fine. Otherwise, you need to replace the fuse.
How To Fix
If the fuses are blown, you should replace them with new ones. You can buy replacement fuses from your local hardware store or online. Once you have the new fuses, simply insert them into the fuse holders and replace the access panel.
3. Your Water Heater Is Not Getting Power
Your Rinnai tankless water heater control panel may also stop working if it is not receiving power. If you search the phrase “Rinnai tankless water heater no power,” you’ll see that the issue can be caused by several issues, including:
A bad circuit board
A tripped GFCI outlet
A faulty outlet
To check if the water heater is getting power, open the unit’s access panel (which should be in the front). Inside, you will see a green light next to the word “power.” The water heater is not getting power if this light is not on.
How To Fix
If you have confirmed that the water heater is not getting power, the next step is to find out why. Check the circuit breaker or fuse box to see if there has been a power surge or outage in your area.
If the issue isn’t related to a power surge or outage, check if you have a tripped GFCI outlet and reset it if that’s the case. Resetting a tripped GFCI should be easy: find the red and black buttons on your outlet’s front and press the red one to reset the outlet.
If none of this restores the power supply to your unit, you will need to contact an expert to come and take a look at the circuit board and the electrical outlets in your home.
4. You Have a Thermal Fuse Issue
A thermal fuse issue occurs when excess heat builds up inside the unit and trips the fuse.
To check if you have this overheating issue, remove the access panel on the front of the unit. Inside, you will see a red light next to the word “fuse.” If this light is on, you have a thermal fuse issue.
How To Fix
If you have a thermal fuse problem, the best course of action is to contact a qualified technician. Fixing a blown fuse is complicated and can be dangerous. Also, you might cause further damage to the unit if you don’t know what you’re doing.
5. Your Sensor Wiring Harness Is on Its Way Out
When the wires on your unit’s sensor wiring harness corrode and break, it can also cause issues with your Rinnai tankless water heater.
To check if you have a sensor wiring harness issue, remove the unit’s access panel. Inside, you will see a white wire running from the control panel to the sensor. If this wire is broken or frayed, you have a sensor wiring harness issue.
How To Fix
If you have a sensor wiring harness issue, you will need to replace it with a new one. You can buy a replacement sensor wiring harness from your local hardware store or online. Once you have the new harness, simply connect it to the control panel and sensor.
This is a common issue and is usually not difficult to fix. But if you are not comfortable working with electrical wiring, it is best to contact a qualified technician.
Final Thoughts
I know this is a lot of information to take in all at once, but it’s the only comprehensive way to troubleshoot your Rinnai tankless water heater control panel. If some of the steps recommended here seem too complicated or risky, don’t hesitate to contact a technician.
However, if you are good with electrical work, you might not need to because you can easily replace the fuse or even the entire control panel. I hope this information helps you get your Rinnai tankless water heater control panel working again without spending too much. All the best!
