State Select Tankless Water Heater Troubleshooting [A Complete Guide]

The most common issues you’d face in your State Select tankless water heaters are:

  • No hot water.
  • Hot water takes too long to get to the fixture.
  • The water isn’t hot enough.
  • Hot water becomes cold and stays cold.
  • Hot water temperature fluctuations.
  • And more.

I’ll cover these issues and the solutions to common error codes in this State Select tankless water heater troubleshooting guide. There’s also a dedicated section for electric tankless heaters. So, let’s dive in!

State Select Tankless Water Heater Troubleshooting [Gas Units]

I’ll explain the main issues you’d face with your State Select gas tankless water heater in this section.

1. No Hot Water

The most common and annoying problem you’ll face with your tankless water heater is getting no hot water at all. There are many potential reasons that can lead to the no hot water issue. The main ones are:

  • The heater is not turned on.
  • Electrical power issues.
  • Gas supply issues.
  • Water supply issues.
  • Frozen unit.
no hot water of state select tankless water heater

Now, let’s look at these issues one by one. If the heater is not turned on, it’s obvious that you’d get no hot water. In terms of electrical issues, the unit should have a 120V 60Hz power supply. So, inspect the voltage with a multimeter to see if there are any electrical issues.

Next, check the gas supply issues. If you use LP as your main source of fuel, you may have run out of it. Check your cylinder and see if that’s the case. If you have natural gas, you may not have turned on the gas valve fully.

If the valve isn’t completely open, the unit won’t get enough gas and you won’t get hot water. On top of that, there could be issues in your gas supply that could lead to low gas pressure or insufficient gas supply. All of those things will cause this no hot water problem.

Next, inspect the water supply. If you don’t open the water supply valve fully, enough hot water won’t go through the heater. So, the burner may not get triggered and you’d get no hot water at all.

If there is dirt in the filter, that could also cause the no hot water issue. The flow rate also needs to be at least 0.5 GPM to trigger the heater. If your hot water fixture can’t draw that GPM, you’ll get no hot water. Finally, a frozen unit will also cause the no hot water issue.


If you’ve turned off the heater, make sure you turn on the power supply. If there are issues with the voltage supply, consult an electrician to fix the issue for you to get hot water again.

Secondly, if you’re using LP and you’ve run out of it, you can refill or replace the cylinder. If you’re using natural gas, check the gas valve first. If it isn’t fully open, make sure you turn it fully perpendicular to the gas lines to let in enough gas.

Issues with gas pressure can also cause this problem. For natural gas, the gas pressure should be between 4.0” W.C. and 10.5” W.C. For propane units, the gas pressure should be within 8.0” W.C to 14.0” W.C.

Check the gas pressure using a manometer. If there are any issues with the gas pressure, contact your local utility company and have them fix it.

Next, it’s time to turn your attention to the water supply issues. If the water supply valve isn’t fully on, make sure you turn it on fully. If there is dirt on the fixtures, you have to clean them to get hot water.

Dirt on the water filter can also lead to you getting no hot water. If the filter turns out to be dirty, follow these steps to clean it:

  • Turn off the power to the unit and close the manual gas shutoff valve.
  • Turn the heater back on, wait for half a minute, and turn off the heater again.
  • Close the water inlet valve and open all hot water faucets in your house. Once the residual water flow comes to an end, you can close the faucets.
  • Place a bucket under the drain plug to prevent any water spillage. Open the drain plugs and wait until all the water is out of the unit.
  • Remove the cold water inlet filter and rinse it with running water. Clean it with a tiny brush if needed to remove all the dirt from the filter.
  • Once the filter is clean, reassemble everything and turn on the power to the heater and the gas supply.

Make sure that there’s a sufficient flow rate as well to trigger the burner of your water heater. If those things are in check, you should have no problem getting hot water from your unit now.

Finally, you have to check if your unit is frozen. A frozen unit can damage the heat exchanger and it won’t even be covered under warranty. There are no quick fixes if you’re facing this issue. However, there are many preventive steps you can take to keep the unit from freezing in the first place.

Here are some prevention methods you can follow so that your heater doesn’t freeze:

  • Use a backflow preventer to limit the amount of air cold air entering the exhaust when you turn off your heater.
  • Make sure your heater is on at all times as the unit needs to have power for the freeze protection settings to kick in as needed.
  • Drain the water out of your heater and disconnect the power supply if you plan on not using your heater for a long time.

Yet, if you find your heater is not heating water, then you can explore our ultimate guide on why State Select water heater is not heating water and how to fix the issues. As the guide includes all types of heaters (tank and tankless-electric & gas), hopefully, you will get the solution.

2. Hot Water Takes Too Long To Get To The Fixture

First of all, the water will also take a long time to get to the hot water fixture if the recirculation pump isn’t active. Even if the pump is active, it may not have proper flow. And finally, the inlet connections or the filters on the return can also be dirty and cause this issue.

hot water takes too long to get to the fixture

Secondly, you need to be aware of if it takes too long to get hot water the length of pipes between the fixtures and the heater. It’s obvious that the water would take longer to travel if it has more distance to cover.

The longer the distance between the hot water faucets and the heater, the more time it’ll take for the water to get to you. You’ll also get colder water compared to your desired temperature if the pipe is exposed.


First things first – if the recirculation pump has been inactive, you have to adjust the settings and make it active. If you do that, you’ll get hot water much faster at the fixtures.

There are two timer settings you can set up to operate the recirculation pump. These two modes are called Timer 1 and 2. The pump will automatically be active based on the time that you set.

You can also press the pump button on the remote control to activate the recirculation pump. The flow rate of the water must be between 2.5 GPM to 4 GPM so that the pump can function properly.

Secondly, you’ll have to accept that it’ll take a long time for the water to come to the fixtures if they’re placed far away. The only thing you can do here is to insulate the piping so that at least the water temperature remains warm.

Finally, clean the inlet connections of the water heater as well. If the flow of water was obstructed due to any blockage, it should be cleared. Now, you’ve done everything you can to make sure that the water flows to your hot water fixtures as early as possible.

3. The Water Isn’t Hot Enough

More often than not, the main reason behind not getting enough hot water is setting the thermostat too low. When you have multiple people using the same heater, someone could have changed the settings while you have no idea. Inspect the display panel of your heater and see if that’s what’s happening.

water isn’t hot enough of state select tankless water heater

The next thing you need to be aware of is gas supply issues. Not opening the gas valve fully, insufficient gas pressure, and using gas pipes of the wrong size can cause this problem.

Besides those common issues, plumbing crossover between the hot and cold water lines can also lead to getting not enough hot water.


If the set temperature is too low, you can easily adjust it. Press the “Hot” button to increase the temperature and the “Cold” button to decrease the temperature on your State Select tankless heater.

You won’t be able to set the temperature higher than 120°F by default. If you want to increase the temperature up to 140°F, you need to bypass the default settings. Follow these steps to do it:

  • Make sure the water heater is in standby mode.
  • Set the temperature to 120°F by pressing the “Hot” button.
  • Press and hold both the “Hot” and “Info” buttons together for at least 3 seconds until you hear a beep from the remote.
  • The temperature will change to 125°F once you hear the beep. You can increase the temperature up to 140°F by pressing the “Hot” button.

If you own a 540HX3 model, you can even adjust the temperature up to 160°F. Just repeat the same steps shown above but you’ll start at 140°F and end up at 160°F.

However, keep in mind that setting the temperature so high increases the risk of scalding. So, you should use a thermostatic mixing valve if you plan to set the temperature that high.

If there are gas supply issues, you already know how to solve them as I’ve explained them in the previous issue. But you may still be confused as to what the right gas line size is. So, here’s a picture to help you out:

right gas line size of state select tankless water heater

Make sure you have a gas line of the right size for your unit. If you don’t already have that, you need to replace the gas lines. Now, you know how to solve all gas supply issues.

If you have installed a new heater and this problem is happening immediately, it could be due to a plumbing crossover. You may have installed the hot water and cold water connections the wrong way. Flip the connections again to solve this issue and have proper hot water.

4. Hot Water Becomes Cold And Stays Cold

If you get cold water all of a sudden when using hot water, there are a few reasons behind it. A dirty water inlet filter, clogged faucets, low flow rate, and not opening the gas supply valve are the most common reasons for the water turning cold.

clogged water faucet of state select tankless water heater


I’ve already talked about how you can solve each of these issues in the previous problems. So, just find the underlying problem and take the right corrective actions to fix it.

5. Hot Water Temperature Fluctuations

Even the fluctuations in the hot water temperature are due to many of the same reasons I’ve explained so far. The main reasons behind it are a dirty cold water inlet filter, a gas line of the wrong size, insufficient gas pressure, and plumbing crossover.

cold water inlet filter of state select 
tankless water heater


If you have the gas line of the wrong size, you need to replace it. If you have insufficient gas pressure, you need to adjust it. Similarly, solve the other issues as you’ve learned in this guide.

6. Error Codes

Sometimes, your heater will make the diagnostic process a lot easier for you. There are certain codes or flashing sequences that’ll tell you exactly what’s wrong with your heater.

When you see any of these error codes, you have to fix the underlying issue that’s causing the error code and the problem will be solved. Here are the most common error codes in State Select gas tankless water heaters:

  • Error 031 (1 Green Flash) – Wrong Dip switch settings.
  • Error 111 (3 Green Flashes) – Ignition failure.
  • Error 321 (2 Green Flashes) – Inlet thermistor failure.


Here’s how you can solve these error codes:

Error 301 – Check the dip switch settings on the PCB and adjust them if needed.

Error 111 – Do these things given below to solve this error code:

  • Make sure the hi-limit switch is working fine.
  • Check the wires and if they’re damaged, replace them.
  • Clean the flame rods if there is soot on them.

Error 121 – This error code could come up due to wiring breakage or inlet thermistor failure. So, replace the wiring if it’s damaged. Otherwise, you have a bad thermistor and it’ll have to be replaced.

Besides these common error codes, there are plenty of other error codes that come up in State Select tankless heaters. Check out our State Select tankless water heater error codes guide to learn about those error codes.

You’ll also find the solutions to the error codes and how you can clear them. The guide contains the fixes for the error codes for both tankless gas and electric heaters.

State Select Electric Tankless Water Heater Troubleshooting [Solved]

You’d face a lot of similar issues in the electric tankless heaters as you would in the gas ones. But as the two heaters operate using different components, the reasons behind the same issue wouldn’t be the same.

Here are the most common faces you’d face in your State Select electric tankless water heaters along with their fixes:

1. Water Is Cold

The main reasons why you can get cold water at the hot water fixtures when using a State Select electric tankless water heater are:

  • Tripped circuit breaker.
  • High flow rate.
  • Failed heating element.
  • Faulty thermistor.
  • Control board failure.
circuit breaker of state select tankless water heater


Check the circuit breaker supplying power to the heater. If it was tripped, flip it back on and your problem will be solved. If the flow rate is too high, reduce it to get hot water.

If either the heating element or the thermistor is faulty, you have to replace them. There are dedicated sections for both of them in this article. Keep on reading to find out about them in detail. If the control board has failed, you also have to replace it.

2. The Water Is Warm But Not Hot

This issue indicates that you get warm water from your heater but it’s not as hot as you expected. In the previous one, you get cold water. But here, you’d at least get warm water.

The reasons behind the previous and this issue are pretty much the same. The only additional thing you need to look out for is if someone sets the temperature too low.


You already know how to deal with the majority of these issues. If the set temperature is too low, all you need to do is to turn it up. In doing that, you should get sufficient hot water from your heater.

3. Hot Water Temperature Fluctuations

When you’re taking a shower, you want the water temperature to be consistent. But if there are bursts of cold water in between, it can be super annoying. The main reasons behind this issue are:

  • The power supply to the heater is interrupted.
  • Too high flow rate.
  • The faulty heating element or thermistor.


The power supply to the heater is normally interrupted when one of the circuit breakers gets tripped. Check if your heater has power. If it doesn’t, reset the breaker to solve this issue.

Reduce the flow rate if it’s too low. If the heating element is faulty, it’ll have to be replaced. The same goes for a faulty thermistor. Once you take the corrective actions, you’ll get hot water from your heater.

4. Unit Clicks When Not Being Used

You may be alarmed to hear clicking noises from your heater when it’s not operational. But there’s nothing to be too concerned about here. It could happen due to the following reasons:

  • Cold water flows in reverse to the water heater.
  • The heater has been in standby mode for a long period.


You can install a check valve to limit the cold water flowing through the water heater in reverse. If that is not the issue, then you have nothing to worry about. It’s normal for the heater to make this noise if it has been inactive for a while. The heater needs to maintain a certain temperature for future use.

5. Error Codes

Apart from the major issues I’ve already talked about, there are plenty of other things that could go wrong with your heater. Thankfully, you don’t have to go through the headache of diagnosing all of them yourself.

Your heater will throw error codes that’ll tell you exactly what’s wrong with your heater. Some of the common codes in State Select electric tankless water heaters along with their meanings are:

  • E03 – The water level is low.
  • E06 – Water temperature is too high.
  • E10 – Open inlet thermistor.


If you’re facing the E03 error code and the water level is too low, you have to turn off the unit and open a hot water faucet. It’ll flush the air from the hot water lines. When the water flows freely from the hot water faucet, you can turn the heater back on.

You can solve the E06 error code the same way. After opening the hot water faucet and running some water through the heater, the error code should go away on its own. If it still remains, you have to contact customer support to help you with this issue.

When you’re facing the E10 error code, you should remove the thermistor in question and reconnect it. If the code still remains, your thermistor is likely faulty and you’d have to replace it.

How To Replace State Select Electric Tankless Heater Heating Element?

If you have a bad heating element, you’ll have to replace it. The tools you’ll need to replace the heating element are:

state select tankless water heater heating element
  • Replacement part (New Heating Element).
  • Adjustable wrench.
  • Pipe wrench or slip joint pliers.
  • Element wrench.
  • Phillips head screwdriver.
  • Bucket, rag, and a hair dryer.

Once you’ve collected these tools, you can follow these steps to replace the heating element in your electric tankless heater:

Step 01: Ensuring Your Own Safety

It’s important that the power supply to the heater should be off when you replace the heating element. So, disconnect the power supply to the heater by flipping the circuit breaker.

If your unit is connected to more than one branch unit, you’ll have to disconnect multiple switches to shut off the power supply to the heater.

Make sure that there is no power to the heater by confirming it with a circuit tester after you’ve flipped the breakers.

Step 02: Remove The Front Panel

Turn on a hot water faucet and let it run until the water becomes cold. Then close the water inlet valve so that cold water can no longer go through the heater. But keep the hot water faucet open. It’ll relieve the pressure.

Now, remove the front panel of the heater and place a bucket under the heater to catch any spilling water.

From here on, the steps will vary depending on whether you have a point-of-use water heater or a two or four-chamber heater.

Keep reading if you have a point-of-use model. If you have a two or four-chamber model, you can skip to “Step 6”.

Step 03: Preparing The Heating Element For Removal

Remove the screws securing the top plate in its position and take off the top plate.

Slide both the outlet and inlet grommets upwards to get some clearance when removing the heating element.

Disconnect the connection between the screws of the heating element and the wires by removing the screws with the screwdriver.

Pull the green ground wire from the heating element and disconnect it.

Step 04: Removing The Heating Element

Use an element wrench to unscrew the retaining nut holding the heating element in place.

Remove the heating element from the water heater by pulling it out. Cover the heating element with a rag as you pull it out so that no water drips to the control board.

Disconnect the brass round ring at the top of the heating element and set it aside for later use.

Step 05: Replacing The Heating Element

Make sure an O-ring is attached above the threads of the new heating element and install the new heating element in place of the old one.

Attach the brass round ring you removed earlier to the top of the new heating element.

Tighten the retaining nut to secure the new heating element in its place. Put the screws connected to the black and red wires and connect them again. Reconnect the green ground wire you had previously removed.

Adjust the outlet and inlet grommets to their original positions. Reinstall the top plate and put the front cover back on to complete the installation.

Step 06: Replacing The Heating Element (For 2&4 Chamber Models)

Unplug the cover’s ribbon cable from the control board. Then remove the screws holding the access plate in place. It’s located at the bottom of the heater.

Take off the access plate and allow the residual water to drain into a bucket. Clean the access plate and both seals. Once you’re sure that the seals are seated properly, you can reinstall the access plate.

Remove the old heating element and place the new one in its place following the same steps shown above.

Regardless of which model you have, turn on the hot water faucet after completing the installation to get rid of the air in the pipes. If you find any leaks, you have to reinstall the heating element until there’s no longer any water coming out.

If there is no leak, you can turn on the power to the heater and wait for a while until it resumes normal operation. Hopefully, you’ll no longer have any trouble getting hot water from it.

How To Replace State Select Electric Tankless Heater Thermistor?

A bad thermistor can cause several issues in your State Select electric tankless heater. Luckily, you can replace it by following the steps below:

state select electric tankless water heater thermistor
  • Flip the breaker to turn off the power to the heater.
  • Drain the water from the heater by opening a hot water faucet. For point-of-use models, you can drain the water by removing the top plate. For two or four chamber models, you can drain the water using the access plate.
  • Locate the faulty thermistor following the error code that came up on your heater.
  • Use a 0.5-inch open-end wrench to rotate the thermistor clockwise and remove it. Make sure that the O-ring is secure before putting in the new thermistor. Install the new thermistor in place of the old one and tighten it.
  • Plug the thermistor wires into the control board and turn on the hot water faucet to bleed the air from the heater and the pipes.
  • If there are no leaks, place the front panel back on and restore power to the heater after a while.

So, that’s how you can replace a bad thermistor in your State Select electric tankless water heater. You should get hot water from your heater soon after replacing a faulty thermistor. 


How to adjust the temperature on State Select electric tankless heaters?

You can adjust the temperature by pressing the up and down arrow buttons on two and four-chamber models. When you’re happy with the settings, you can hit the “Enter” button to finalize the desired temperature.

Is it okay for the fan to spin after the operation of the heater is off?

It’s normal for the fan motor to keep running for at least 15 to 70 seconds so that the heater can be re-ignited quickly and purged out of the gas.

What to do if your State Select tankless water heater makes an unusual noise?

If your tankless water heater makes a noise all of a sudden, it could be a serious issue. So, contact the support team at 1-877-737-2840 to find out more about it.

Is there any temperature adjustment knob in the circuit board of State Select electric tankless heaters?

There’s a temperature adjustment knob on the circuit board of State Select electric tankless heaters. You can rotate it clockwise with a flat blade screw to increase the temperature and counterclockwise to decrease the temperature.

How does the flash sequence work in State Select electric tankless heaters?

There are two digits in the flash sequence. Let’s say you have a 3-4 flash sequence. The red LED light will flash 3 times at first, then the green LED will come on once, and the red LED will flash 4 times.


You’ve learned about both gas and electric tankless heaters in this State Select tankless water heater troubleshooting guide. Depending on which type of unit you own, the causes behind these issues can vary.

Hopefully, all the problems are clear to you by now and you can fix them on your own.

Well, you can check out our Suburban RV water heater troubleshooting guide if you have a Suburban water heater & have issues with your heater.

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