Suburban Water Heater Won’t Light Or Stay Lit: Fixing 12 Issues

It can be incredibly frustrating when you’re looking forward to taking a nice hot shower, but your water heater just won’t stay lit. So what can be the possible reasons behind the issue – Suburban water heater won’t light or stay lit.

  • Power Supply Issue
  • Low Gas Pressure
  • Tripped High Limit Switch
  • Faulty ECO
  • Wire Connection is not secured
  • Dirty Pilot Tube/Damaged Pilot Assembly

Also, defective Igniter, thermostat, control board or blocked burner tube, and malfunctioning thermocouple are also some common reasons why your water heater will fail to light. 

However, the most common fixes include cleaning or replacing the thermocouple, ensuring no air in the gas line, ensuring proper power supply and gas pressure, etc.

Well, without trying to inspect all the problems, you can never figure out the actual issue. So to understand the main reason you’ll have to explore the article. So, let’s move forward.

suburban water heater won't light or stay lit

Suburban Water Heater Won’t Stay Lit: Quick Overview

Before I get into the main segment let’s learn about the problems and solutions at a glance. 

Power Supply Issue1. Ensure a reliable power supply
2. Consider using a voltage stabilizer
3. Replace the circuit breaker
Low Gas Pressure1. Check and reset the propane tank valve
2. Move the auto-changeover regulator or change the propane tank positions
Tripped High Limit Switch1. Reset the high-limit switch
2. If it trips again, replace the switch
3. Clean the flue using a vacuum cleaner and duct cleaner
Faulty ECOReplace the ECO
Wire Connection is not securedSecure or fix any faulty/displaced wires
Dirty Pilot Tube/Damaged Pilot Assembly# Clean the pilot tube
# Replace the pilot assembly
Defective IgniterReplace the igniter
Defective Thermostat1. Inspect and fix wiring connections
2. Replace if faulty
Blocked Burner TubeReplace the burner tube
Air In Gas Line1. Turn on the heat multiple times to eliminate stale air
2. Use a bleeder valve to remove air from the system
Faulty/Dirty Thermocouple1. Test and replace the thermocouple if faulty
2. Clean the thermocouple if dirty
Faulty Control BoardContact the manufacturer for a new control board

Suburban Water Heater Won’t Light or Stay Lit: Detailed Guide

Now, you’ll learn all the mentioned problems and solutions with detailed explanations. So keep reading.

1. Power Supply Issue

Did you know: Your suburban electric water heater will not function properly unless you ensure a current delivery between 13 to 15 volts? 

At least you’ll have to ensure a constant power of at least 12 volts.

So, if the voltage is unstable, especially below 12 volts the heater will face different issues including not being lit up.

Again if the voltage is more than sufficient level, the circuit breaker will be tripped.

How To Fix It:

The actual fix here is to ensure the voltage and to do so ensure a reliable power supply. However, if it’s not possible then you can try using a voltage stabiliser for the water heater though it’s not a recommended solution as it becomes another hassle to carry. 

Again for any reason if the circuit breaker is tripped replace the circuit breaker. 

2. Low Gas Pressure

The LP (liquid propane) side of your water heater needs a specific propane pressure called “11 Water Column Inches” to work correctly. However, you can’t check this pressure without specialized equipment.

To get an idea if the propane flow is sufficient, you can use your RV furnace as a temporary substitute for the actual equipment. The heater relies on a steady supply of propane to function properly. If the heater is working fine, it indicates that the propane flow should be adequate for your water heater as well.

How To Fix It:

Check the below guide to solve this issue. 

  1. The very first step here is to check and refill the fuel tank.
  2. If there is already enough fuel try resetting the overflow protection. In order to reset the overflow protection device, first, turn off the valve of the propane tank you are currently using. Now, wait a few seconds before going to the next step.
  3. Carefully reopen the tank valve. This might help reset the device and restore proper propane flow.
  4. If the above step does not resolve the issue, you can try moving the auto-changeover regulator to the other propane tank.
  5. If the problem still persists, consider changing the positions of the propane tanks.
  6. Finally, if none of these steps solve the problem and you continue to experience propane flow issues, you’ll have to replace the auto-changeover regulator.

3. Tripped High Limit Switch

When a water heater exceeds a certain temperature, the high-limit switch activates and shuts off the heater. This feature helps protect against potential hazards. If the high-limit switch is tripped, it can cause your water heater to shut off or not stay lit.

tripped high limit switch of suburban water heater

One more reason is responsible for tripping the high limit switch – jammed flue.

The flue is like a chimney that lets out the hot air from your water heater. If the flue gets blocked, it traps the heat inside the heater. When this happens, the heater can get too hot, and therefore high-limit switch is tripped. So, for safety reasons, it automatically shuts down therefore the heater won’t stay lit.

How To Fix It:

Here the fix for the first reason is very easy. Just reset the high-limit switch and the problem should be fixed. In rare cases, you see the high-limit switch trips again after starting the heater. It means the switch is defective and requires replacement. 

Now the fix for the second reason is a bit complex. However, I’m trying to provide an easy guide to clean up the flue.

Step 1: Turn off the gas supply to the water heater.

Step 2: Now, get a vacuum cleaner and connect it to an extension cord. Check if you can remove the vent hood above the water heater. Use the vacuum extension to reach deeper into the vent.

Step 3: Put the vacuum hose and extension into the vent above the water heater. Vacuum up any debris or dirt you can find in that area.

Step 4: For the unreachable parts of the vent, use a duct cleaner. Rub the smooth end of the cleaner inside the vent to remove all dust and pollen particles.

Step 5: Once you have finished cleaning, put everything back in place, including the vent hood.

 4. Faulty ECO

A faulty ECO (Energy Cut-Off) can also be a reason why your water heater fails to ignite. When you turn on the switch, you should hear a clicking sound from the gas valve. If you don’t hear it, it might be due to an issue with the ECO setting.

faulty eco of suburban water heater

The ECO switch is connected between the control board and the gas valve, and it is also linked to the thermostat. Its role is to provide an electrical connection to the gas valve. However, if the ECO malfunctions, the gas valve won’t receive electricity, causing your RV’s water heater to remain off and unable to turn on.

How To Fix It:

First, get a voltmeter and check if there is a reading of 12 volts. If the voltage reading on the voltmeter is off by more than a millivolt, it suggests that the ECO (Energy Cut-Off) may be faulty. Consider replacing the ECO to ensure the proper functionality of the water heater.

Additionally, it is recommended to replace the thermostat as well. The thermostat works in conjunction with the ECO to regulate the temperature and control the operation of the water heater. A malfunctioning thermostat can also contribute to the improper functioning of the water heater.

5. Wire Connection Is Not Secured

Sometimes the problem can be nothing serious like the problem is just with the wires. If the wire gets displaced or is not any more secure then it can cause the issue – the Suburban electric hot water heater will not stay lit.

How to Fix It:

To fix it you’ll have to check the wire connection according to the wiring diagram. If you aren’t familiar with the wiring diagram then call for a professional and fix the faulty/displaced wire. 

6. Dirty Pilot Tube Or Damaged Pilot Assembly

Do you know – “Why does my hot water heater only stay lit for a few seconds?”

Your water heater only stays lit for a few seconds because of the dirty pilot tube. If you’re not using the heater for a long time, it can get dirty being idle including the pilot tube, and cause this issue. 

Again, if the pilot assembly of your Suburban RV water heater is damaged, it can cause the heater to fail to stay lit. 

How to Fix It:

To fix the first problem you’ll have to clean the pilot tube. Take a dry cloth or sandpaper to clean the pilot tube.

And for the second one, there is only one solution – replace the pilot assembly. 

7. Defective Igniter

If the igniter is defective, it won’t be able to turn on the burners. As a result, your suburban RV water heater will not stay lit.

To check if the igniter is the issue, look for sparks when the water heater tries to ignite. If you don’t see any sparks, it means the igniter is most likely faulty.

How To Fix It:

The best way to fix this issue is to replace the igniter. If you aren’t used to this work then look for a professional.

8. Defective Thermostat

If the thermostat is defective it may fail to transmit a consistent signal or may send incorrect signals to the ignition system. As a result, you can face issues like a suburban gas water heater won’t stay lit.

How To Fix It:

  1. First, inspect the wiring of the thermostat. To do it properly, check the owner’s manual for a wiring diagram to guide you. Check if there are any damaged wires and fix them if found. Also, ensure that all connections are secure and not loose.
  2. If the problem isn’t solved yet after checking the wiring, you can test the thermostat using a multimeter. If the reading shows no continuity (infinite resistance) or inconsistent reading then the thermostat is faulty. Replace it to fix the issue.

9. Blocked Burner Tube

When there are dust or calcium deposits, it can block the burner’s opening. This blockage can prevent the burners from lighting correctly.

How To Fix It:

Here the solution is to replace the burner.

Here are the step-by-step instructions to replace the burner tube of your water heater:

Step 1: Turn off your Suburban hot water heater and open a nearby tap for about five minutes. This will allow the water to cool down.

Step 2: Now find the lower access panel and then remove it. You should find the panel at the bottom of the unit.

Step 3: Unscrew and remove the base of the old burner tube from the gas valve to the pilot light. Take out the old tube and set it aside.

Step 4: Install the new burner tube in place of the old one.

Step 5: Using an adjustable wrench, securely attach the base of the new burner tube to the gas valve. Tighten it and ensure a snug fit.

Step 6: After completing the installation, turn on the water heater to check if it is working properly. Observe if the burner ignites and heats the water as expected.

10. Air In Gas Line

Haven’t you used your Suburban water heater for a long time? Unfortunately, sometimes it can accumulate a significant amount of dusty air. When this happens, the flame can easily go out, and sometimes it may not even ignite at all.

How To Fix It:

There are 2 ways to fix it. If you’re lucky enough then, turning on the heat several times can help you eliminate the stale air. 

If it doesn’t work then follow the step-by-step guide

Note: Start by attempting to pump the air out of the system using the following steps. If this method doesn’t work, proceed to step 3.

Step 1: Turn off the water heater completely and locate the air vent or bleeder valve on the water heater. You should usually find it near the top of the unit.

Step 2: Attach a hose to the bleeder valve and direct the other end of the hose into a suitable drain or container.

Step 3: Open the bleeder valve by turning it counterclockwise. Let the water flow out of the valve until a steady stream is achieved. It indicates that the air is being expelled.

Step 4: Once you observe a steady stream of water, close the bleeder valve by turning it clockwise.

If the air removal process is still unsuccessful, proceed to the next step.

Step 5: Turn on one or more burners.

Step 6: Keep the burners on for approximately 15 to 20 seconds. Also, allow them to burn off any remaining air in the system.

Step 7: Observe the flame on the burners. When the flame appears blue and stable, it indicates that all the air has been burned out and the problem is solved. 

11. Faulty/Dirty Thermocouple

Another common reason for a Suburban water heater won’t stay lit is a bad or dirty thermocouple. If you’re not familiar with it you might like to know what is a thermocouple on a water heater.

faulty thermocouple of suburban water heater

A thermocouple is an apparatus designed to identify the presence of the pilot flame. It enables the gas valve to open and ignite the burners.

Now the thermocouple can cause the heater won’t light problem in different ways. Below I’m mentioning 2 reasons.

  • First, if the thermocouple is broken the gas will cut off and won’t be able to reach the burner and the pilot. 
  • Next, if the thermocouple is dirty, it can interfere with the flow of electric current from the pilot. And it may result in a gas outage and therefore your suburban water heater will not stay lit.

How To Fix It:

To fix the first issue you’ll have to check the thermocouple whether it is faulty or not. So, let’s start by checking the thermocouple –

Step 1: Close the propane gas valves by turning them off and find the thermocouple (Follow the added image above)

Step 2: Take out the thermocouple carefully.

Step 3: Now use a digital electrical tester with a millivolt scale.

Step 4: Set the burner control valve to the “pilot” position and press the pilot button.

Step 5: If the thermocouple is working correctly, it should generate electricity between 25 and 30 millivolts.

Step 6: If the thermocouple doesn’t generate enough electricity, that means the thermocouple is faulty.

Now come to the solution. The most effective solution for a faulty Suburban water heater thermocouple is to replace it with a new one.

Now if the thermocouple is dirty just properly clean the thermocouple. 

If you don’t know the right process to clean the thermocouple then check out the given video – How To Clean A Thermocouple For A Gas Water Heater (D.I.Y.)

12. Faulty Control Board

The next potential reason your suburban water heater SW6DE won’t stay lit is a malfunctioning control board. But how does it happen?

faulty control board of suburban water heater

If the control board is faulty, it may send incorrect or inconsistent signals. As a result, the heater will face different issues like won’t stay lit, undesired shutdown, and others. This can happen even if the thermocouple is functioning properly.

How To Fix It:

This time the fix is quite expensive. Just reach out to the manufacturers and ask them for a new control board or just ask them for the model of the control board. Then you’ll have to replace the control board.

Tip: When it comes to replacing the control board of your Suburban water heater, it is highly advisable to enlist the services of a professional technician. They have the expertise and experience to properly handle the installation and ensure that it is done correctly and safely.

A General Solution To Suburban RV Hot Water Heater Won’t Light – Reset It

I’ve already explained several causes of the issue of the Suburban RV water heater not lighting. But here’s a quick tip, just reset your Suburban RV water heater and sometimes you’ll find the issue solved. So, how do I reset my suburban water heater?

  1. First, check the front of the Suburban water heater unit and you’ll find the restart button. 
  2. To reset the Suburban water heater, use your finger or a small tool to press the reset button. Apply gentle pressure until you feel or hear a click, indicating that the button has been successfully reset.
  3. Now just wait for a few minutes to allow the water heater to reset and calibrate.


How much does it cost to replace a water heater element?

It should generally cost you between $200 to $300 to replace the water heating element. However, the price may vary from model to model.

Why does my RV water heater fire up then go out?

If your RV water heater fires up and then goes out, most probably it’s the flame issue. To fix this problem, first, check whether the propane and fuel source are functioning correctly. Next,  inspect your ignition or pilot light lastly, check the thermocouple.

How much does it cost to replace a thermocouple?

If you want to replace a thermocouple then it should only cost between $20 to $25. However,  the surprising fact is if you want to repair it then it’ll cost around $150.

What causes ECO button to trip?

When the temperature of the water in your water heater exceeds a certain level, it triggers the emergency cut-off, also known as the ECO. More simply, if the water becomes excessively hot, it will activate the reset button of your Suburban RV water heater.

Final Words

That’s all about the problem – the Suburban water heater won’t light or stay lit. 

I’ve added 12 possible reasons with solutions and a general fix. By noticing the problem we’ll see many of them are due to the accumulation of dirt and debris. So, here I got a tip for you. To prevent dirt/calcium deposits and scale buildup, clean and descale the water Suburban RV heater tank at least once per year.

Now, whatever the issue is I suggest before you do anything turn off the heater and let it cool down. And If you’re not a pro in this field, get help from a professional.

Now before I leave I would suggest another article I’ve recently covered on Suburban RV water heater not getting hot enough.

That’s all for now. See you again soon and cover up another problem. Good Luck!

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