Are you struggling with the status light codes or error codes on your State water heater for a long time? Look no further! We have a comprehensive guide for you on State Select water heater light codes, well-described with the error meaning and the proven tips to erase the codes.
The most frequent error codes on the State Select gas tankless water heater are 031, 101, 111, 121, 311, 321, 331, 391, 441, 510, and so on, signaling different issues in the system. At times, resetting the water heater can help you to resolve the issue. Or, you may clear the codes by turning off the water supply to the system.
But that’s not always the right approach to solve the errors. Let’s dive right in to get the details!
Table of Contents
State Select Water Heater Light Codes [Both Gas & Electric Models]
The error codes or light codes on the State Select water heater mean the unit is operating normally or it’s malfunctioning. To figure out the actual reasons for the appearing code and troubleshoot your State Select tankless water heater issues, it’s essential to track down the meaning of it.
And only then you will be able to find out the solutions. The codes and related meanings will differ for the gas and electric models.
Don’t worry! Here is a complete chapter for you, disclosing all the error codes of State Select tankless water heaters for both gas and electric models. Let’s start:
State Select Water Heater Error Codes (For Gas Tankless Models)
If you have a State Select water heater on any of the gas tankless models, encountering the error while in operation is quite obvious. For instance, I have an effective error code list for you, highlighting the meaning and effective fixes.
Go through the corrective solutions for the appearing code and fix the troubles in a shorter time.
Error Code | Symptom |
031 | Incorrect Dipswitch Settings |
101 | Warning for 991 Error Code |
111 | Ignition Failure |
121 | Flame Loss |
311 | Output Thermistor failure (110U & 310U Models)Heat exchanger thermistor failure (510U model) |
321 | Inlet thermistor failure |
331 | Outlet thermistor failure (510U model only) |
391 | Air-fuel ratio rod failure |
441 | Flow sensor failure (Only Easy-Link & Multi-Unit Systems) |
510 | Abnormal main gas solenoid valve |
551 | Abnormal gas solenoid valve |
611 | Fan motor fault |
651 | Flow adjustment valve fault (Only Easy-Link & Multi-Unit System) |
661 | Bypass valve fault (510U model only) |
701 | Computer board fault |
711 | Gas solenoid valve drive circuit failure |
721 | False flame detection |
741 | Miscommunication between the water heater and remote controller |
751 | Miscommunication between the water heater and the built-in controller |
761 | Miscommunication in the Easy-Link system |
991 | Imperfect combustions |
1. Error Code 031
If the remote controller displays the error code 031, it is a sign of the incorrect DIP switch connection on the control board.
How To Fix:
Turn off your State Select water heater and remove the front cover to access the PCB. Now inspect the DIP switches setting on the board. Fix the faulty connections with the help of a professional.
2. Error Code 101
The fault code 101 displayed on the controller is the warning for the error code 991.
How To Fix:
When you are sure about that, inspect the gas supply lines for air blockage or stuck debris. Purge the air from the gas line and remove the obstruction.
Also, clear off any blockages from the air intake and exhaust venting. When done, ensure there is enough distance between the air intake and exhaust as per the instructions in the user manual.
Next, inspect the combustion to check for any debris in the burner assembly. Clear off the shoots and debris from the burners and fan motors as well to ensure a fluent combustion process.
Finally, inspect the altitude/elevation area where the water heater is installed. Make sure the proper installation of the water heater.
3. Error Code 111
If the remote controller flashes 111 error about three times, it warns you about the ignition failure in the system.
How To Fix:
First off turn off your water heater before inspecting any of the elements inside. When done, remove the front cover. Then access the hi-limit switch to ensure that is functioning properly.
Inspect all the wiring connections and look for any damage or breakages. Fix or replace the worn-out wiring. Look for burn marks on the control board and replace the board if needed.
When done, inspect the flame rod, igniter, and burner assembly. Clean off the build-up shoots and debris from the elements. Also, check if the heat exchanger is leaking or dripping and fix that with the help of a professional.

Finally, reassemble your water heater and turn on the gas supply. While doing so, make sure you are using the right type of fuel for ignition and the tank is not empty if you are using LP gas.
Now this point, check whether the buzzing spark ignition sound coming from the burner and the “clunk” sound is coming from the gas valve assembly. If so, you need to contact a professional to diminish all the trouble points from the heater.
4. Error Code 121
While in operation you may notice that your State water heater is not heating water and the display flashes the error code 121. It is the error sign of the lost flame in the system.
How To Fix:
To fix the lost fame of your State water heater, do the following:
- Start by quickly checking whether you have turned on the gas supply and whether there is sufficient fuel supply to your heater. If so and still the error code appears, turn off your water heater and inspect the hi-limit switch to ensure that is functioning properly.
- Now look for stuck grease, oil, and shoots on the flame rod, igniter, and burner assembly. Clean off all the dirt and debris.
- Then inspect the heat exchanger as well to see whether it is leaking. If so, fix it and replace it in case it is beyond repair.
- Finally, look for any damage on the control board and replace it if needed. I recommend contacting a professional for further discussion.
5. Error Codes 311, 321 & 331
The error code 311, 321 & 331 are the fault indication from the system, signaling you about defective thermistors.
How To Fix:
If you have a State Select water heater on 110U & 310U models, inspect the wiring connection to the outlet thermistor. Clean off the clogged thermistor and replace it if needed. Also, check and replace the heat exchanger thermistor if you have a 510U model.
In case of appearing fault code 321, replace the inlet thermistor. Finally, if you see 331 error codes on the display, inspect and replace the faulty outlet thermistor (510U model only).
6. Error Code 391
Controller flashing 391 error indicates the failed air fuel rod in your State gas tankless water heater.
How To Fix:
Inspect the AFR for any blockage and damage. Clean the rod if it is clogged with debris. Verify the wiring connection to the AFR is in well working condition, if needed you may need to replace the faulty AFR.
7. Error Code 510 & 551
If you see the error code 510 or 551 on the control display of your State gas tankless water heater, be sure the abnormal main gas solenoid valve is the root reason behind this.
How To Fix:
Inspect the gas solenoid valve for any loose and faulty wiring connections. Replace the valve if needed. If still, the same error blinks, look for the burn mark on the control board. Head to a professional one for further troubleshooting.
8. Error Code 661
The faulty fan motor of the system is the root culprit for flashing error code 661 on your State Select water heater.
How To Fix:
Turn off your water heater and remove the front panel and the elements of the heater inside. Now, locate the fan motor location and look for any faulty wiring connection going to the motor assembly.
If possible, fix the loose wiring. Then, check for any frozen and corroded connection to the motor.
If needed, you may need to replace the bad motor to get back the heater into normal function.
9. Error Code 651
The faulty flow adjustment valve of the State Select water heater is the root culprit to blame if you have a 651 error flashing on the display.
How To Fix:
Inspect the flow adjustment valve to see whether it is clogged with scale buildup or has water leakage. Clean off the specks of dirt and fix the damaged portion. Verify a snug wiring connection to the valve assembly. If needed, replace the faulty valve.
10. Error Code 661
A defective bypass valve is the main reason for the 661 error code on the control display of your State Select gas tankless water heater.
How To Fix:
Inspect the bypass valve for connection/ breakage of wires and fix them. Also, look for obstruction on the valve assembly and clean it. Replace the faulty bypass valve.
11. Error Code 701
The 701 error code on the control display of the State Select gas tankless water heater defines the faults in the computer board.
How To Fix:
Inspect the outlet thermistor and chances are it is obstructed with shoots and scale buildup. If so, simply clean it. Also, look for corroded and faulty wiring connections in the system and fix them.
12. Error Code 711
The error code on the State Select gas tankless water heater is a sign of the failed gas solenoid valve drive circuit in the system.
How To Fix:
The fixing steps will be the same as the solution for error codes 111 or 121. Go through our list above and figure out the solution to erase the code from your water heater.
13. Error Code 721
If you have a 721 error code on your State Select tankless water heater, I bet it is a sign of the detected false flame in the system.
How To Fix:
First off, inspect the condensate drain line to see whether it is installed on the vent collar of the water heater. Also, ensure there is no leakage in the heat exchanger.
14. Error Code 741
Whenever there is a miscommunication between the water heater and the remote controller, you will get the error code 741 on your State Select water heater display.
How To Fix:
Inspect the connection between the water heater and the remote controller. Fix or replace the damaged portion. Finally, ensure a proper power supply to the system.
15. Error Code 751
Whenever there is a miscommunication between the water heater and the built-in controller, you will get the error code 741 on your State Select water heater display.
How To Fix:
Inspect the connection between the water heater and the built-in controller. Fix or replace the damaged portion. Finally, ensure a proper power supply to the system.
16. Error Code 761
The error code 761 on the State Select water heater defines the miscommunication in the easy-link system.
How To Fix:
Inspect the connections between the parent unit and the child units to see if they are correct. You need to verify that each unit has power. For instance, check and turn on the power switch above the computer board.

17. Error Code 991
991 flash code on the remote display is the error, signing you about imperfect combustion in the State Select water heater system.
How To Fix:
Go through the exact corrective actions that I’ve mentioned as the solutions for error code 101 above.
State Select Water Heater Error Code [Electric Tankless Models]
This chapter is going to disclose to you all the error codes for the State electric tankless water heater for both point-of-use models and 2 and 4-chamber models:
i) Error Codes For Point-of-Use Models
If you have a State Select water heater in Point-of-use models, you will find an error on the LED circuit board as a flash pattern.
- The codes will flash in two digits in two different colors.
- The first digit will flash in red color.
- A green color will separate the first and second digits.
- The second digit of the code will flash in again red color.
Confused? See the example below:
Flash Code Sequence: 3-6
3 red flashes- green flash – 6 red flashes
Now go through the below comprehensive list of the error codes in Point-of-use models with the exact meaning and corrective solutions:
Flash Code Sequence | Error Meaning |
1-1 | Disable switch open |
1-2 | T-IN thermistor is open |
1-3 | The T-OUT thermistor is open |
1-7 | The controller has detected the exceeded water temperature (above 145°F) |
1-8 | Leak detected |
2-1 | Insufficient water in the tank |
3-4 | Critical error |
3-6 | Freeze warning |
1. Flash Code 1-1
The flash code in the LED of the State electric tankless water heater is the error indicating that the hardware jumper is not installed or not in place on the circuit board.
How To Fix:
Inspect the circuit board and look for the missing jumper on the board following the manual. You need to make sure that both jumpers are in place.

2. Flash Code 1-2
If your LED status lamp on the circuit board flashes the error code 1-2, be sure it means the condition of an opened T-IN thermistor.
How To Fix:
Inspect the wiring connection to the T-IN thermistor and fix the loosened one. If needed, replace the faulty T-IN thermistor.
3. Flash Code 1-3
The flash code in the sequence of 1-3 on the circuit board LED lamp tells you about an opened T-Out thermistor.
How To Fix:
First off, inspect the T-Out thermistor for faulty wiring connections. Replace the thermistor if it is worn out or completely damaged.
4. Flash Code 1-7
When the water temperature rises above 145°F, the controller detects it and starts flashing code 1-7 in the LED status indicator light.
How To Fix:
Whenever you will encounter this flash code on the LED lamp, turn off the power supply to the heater to avoid scalding. Then open a nearby hot water fixture and let the water run through the system for about 5 minutes.
When done, inspect the temperature sensors (thermistors) to verify their condition. Take a voltmeter and check the resistance of the sensors.

It should give the same reading. If the resistance of one thermistor is higher than the other, replace the bad one.
If still, the issue persists, it signs you that the circuit board isn’t functioning more. Replace it with the help of a professional.
5. Flash Code 1-8
When the leak sensor of the State Select gas tankless water heater detects leakage in the system, it will flash an error code in the sequence of 1-8 on the status light.
How To Fix:
First, turn off the power supply to your water heater. Then, check the complete system for any water leaks and fix the damaged point.
Inspect the leak sensor and circuit board and dry the components to ensure there is no sign of water.
Finally, restore the power to the water heater and check whether it is working as it should.
6. Flash Code 2-1
The flash code on the LED indicator light of the State Select electric tankless water heater is the error sign of lack of water in the system.
How To Fix:
Inspect the water supply valves and backflow preventer for any restrictions. If so, remove the obstruction to ensure proper water flow in the system. The heater should be full of water and there is no air trapped inside.
If you are sure about sufficient water in the heater, connect the level detects spades on the circuit board to the ground. If you hear a clicking sound while running the water into the system, check the elements for any damage and fix it. If needed, seek the help of a professional for better assistance.
7. Flash Code 3-4
The flash code 3-4 on the LED indicator light informs you about the critical situation of the heater.
How To Fix:
Check whether the controller is showing another code meanwhile. If so, figure out the meaning of the error and fix it.
8. Flash Code 3-6
The flash code 3-6 on the status lamp of the State Select electric tankless water heater is the warning of the freezing condition in the system. This mostly happens due to an opened T-IN thermistor when it detects the temperature of the incoming is lower than 40°F.
How To Fix:
Inspect the T-IN thermistor to check the fault lies in this element. If so, you just need to replace it.
If all is okay, turn off the power supply to the water heater and close all the supplies to the system.
Then drain all the water from the heater. Wait until the temperature of the incoming water rises above 40°F and then turn on the water heater.
ii) Error Codes For Two And Four-Chamber Models
If you have a State Select electric tankless water heater in Two And Four Chamber models, here we have a comprehensive list of error codes that you may encounter while operating.
Display Codes | Error Meaning |
E02 | The heated water has exceeded the temperature limit. |
E03 | The low water level in the water heater |
E04 | A leak is detected in the heater |
E06 | The software determined that the water temperature is too high |
E10 | The inlet temperature sensor is open |
E11 | Open thermistor TH-1 open (For 2-and 4-Chamber) T-Out Opens (For point-for-use models) |
E12 | Open thermistor Outlet thermistor open (For 2 Chamber models) TH-3 Open (For 4 Chamber models) |
E13 | TH-2 thermistor is open (For 4 Chamber models) |
E14 | The outlet thermistor is open (For 4 Chamber models) |
E20 | The inlet thermistor is shorted |
E21 | Shorted thermistor TH-1 open (For 2-and 4-Chamber) T-Out Opens (For point-for-use models) |
E22 | TH-2 thermistor is shorted (For 2 Chamber models) TH-3 thermistor is shorted (For 4 Chamber models) |
E23 | TH-2 thermistor is shorted (For 4 Chamber models) |
E24 | TH-4 thermistor is shorted (For 4 Chamber models) |
E51 & E52 | Communication failure with the control board |
1. Error Code E02
When the hardware detects that the outlet water temperature has exceeded the temperature limit, it shows the error E02 on the control display.
How To Fix:
Whenever you encounter the E02 code on the display, turn off the power supply to your water heater immediately. Then head to a professional to figure out the trouble points of the heater.
2. Error Code E03
E03 error code on the State Select water heater control display informs you about the water level condition going through the heater. When there is a lack of water in the system, the controller throws this code as a diagnostic error.
How To Fix:
Start by turning off the power supply to your water heater. Then head to the nearby hot water faucet of your water heater and turn it on. It will flush out all the remains water and air from the water line.
When the water will run from the hot water heater without any distraction, restore the power supply to your water heater and then check for the faulty code.
3. Error Code E04
When the controller detects a leak in the system, it shows the fault code E04 on the display.
How To Fix:
Whenever you will have an E04 error code on the display, turn off the power supply and call a technician for any technical support.
4. Error Code E06
When the software determines that the water temperature is too high, it will show the code E06 on the control display as a diagnostic error code. It mostly happens when you have just powered up your water heater.
How To Fix:
Just after appearing the error code, turn on a hot water fixture nearby of your water heater. The fault code will clear. If not, turn off the power supply to your water heater and contact customer service.
5. Error Code E10
The error code E10 on the control display of your State Select water heater tells you that the inlet temperature sensor is open.
How To Fix:
Start by turning off the power supply to your water heater. Inspect the thermistor for any faulty connection. If needed, disconnect the thermistor to verify the condition. Replace the defective thermistor. Finally, restore the power supply to your water heater.
6. Error Codes E11, E12, E13 & E14
E11 & E12 fault codes on the Status Select water heater tell you that the thermistors are open. In the case of an E11 error code, you will have the TH-1 open in your 2- and 4-chamber models, and for the point-for-use model, the code defines an open T-Out condition.
On the contrary, if you have the E12 code, it tells you about the outlet thermistor open for the 2- and 4-chamber models. And in the case of the point-for-use model, it is about the open TH-3.
E13 code on the Status Select water heater is the error indication of an open TH-2 thermistor. In the case of the E14 code, it appears only the 4-chamber Status Select water heater, signaling the open outlet thermistor (TH-4).

How To Fix:
Go through the same fixes that I’ve described as the solutions for E10.
7. Error Code E20- E24
The fault code E20, E21, E22, E23, and E24 on the Status Select water heater, all are error indication of shorted thermistors in the system.
How To Fix:
- If you have an E20 code, inspect the inlet thermistor and replace it.
- For the E21 error on the 4-chamber and point-for-use model, replace the shorted TH-1 & T-out thermistors.
- For the E22 error code on the 2-chamber Status Select water heater, replace the shorted TH-2 thermistor. And if you have a 4-chamber model, you need to replace the TH-3 thermistor for the same code.
- Inspect and replace the worn-out TH-2 thermistor of your 4-chamber model in case of an E23 fault code.
- Finally, if you are encountering the E24 error code on your 4-camber State Select water heater, replace the fault TH-4 thermistor.
8. Error Code E51 & E52
E51 & E52 error code on the State Select electric tankless water heater has the same error meaning, signing you about the communication failure. That means the user interface has lost the connection with the control board.
How To Fix:
When you have any of the fault codes between E51 & E52, turn off the power supply to your water heater and call for a technician to diagnose the codes.
FAQs:
Why does my State Select water heater not ignite when the water goes through the unit?
If the water heater doesn’t ignite, ensure the proper water flow rate going through the heater. For instance, inspect and clean the water filter. Look for reverse connection and cross connection. Also, check if the gas supply is turned on.
How to fix water temperature fluctuation in my State Select water heater?
First off, inspect and clean the filter in the cold water inlet. Adjust the gas pressure within the specified limit. Also, make sure the gas line is sized properly and there is no cross-connection between cold and hot water lines.
How to drain all the water from my State electric tankless water heater?
Make sure you have turned off the power supply to your water heater. Then open a nearby hot water faucet and close the inlet valve to relieve pressure. Now remove the cover and place a bucket to catch the water that spills.
In Closing
The error codes on the State Select water heater indicate that the specific part of the unit is not working properly. To fix the issue, you just need to find out the reason behind the light code and then head to the corrective actions to resolve the problem. But before that, what you should learn is how to read the code properly.
Fortunately, I’ve discussed everything you need to know about State Select water heater light codes. Follow our suggested troubleshooting tips to solve the issue by yourself and save the costs of the technician.
Well, if you want to know about the temperature setting of your water heater in detail, you can read our complete guide on how to set State Select water heater temperature.
Also, you can check out our comprehensive troubleshooting guide on State Select tankless water heater in case you face any issues with your water heater.
Good Luck!