Understanding and Troubleshooting Popping Noises in Your Dometic RV Propane Water Heater

Lately, when I turn on my RV’s water heater, powered by propane, it starts just fine but as it’s heating up, but then it makes a strange noise; like a small explosion, or a poof! Obviously, this makes me a little nervous when dealing with open flame like that, so I wanted to get this figured out ASAP. I should mention that I live full-time in a 2011 Georgetown class A, and it still has the original water heater making it about 12 years old.

What could be causing my RV water heater to make popping noises? Here we’ll look at these issues, how to troubleshoot them, and how to resolve them. By the end of the article, you should be confident enough to figure out and remedy your RV’s propane powered water heater issues.

Troubleshooting RV Water Heater Noises

The first step is to remove the cover of your water heater and observe what the flame looks like as it’s burning. Please be careful when doing this! The cover can be hot, the components of the heater can be hot, so be careful and put on some work gloves.

What you’re looking for: Look at the color of the flame as it burns. What’s happening? Is it blue? Is it orange? Is it inconsistent? What do those colors mean?

Blue Flame

• A steady blue flame means the propane is burning efficiently and the air-to-fuel ratio is correct. This is what you want to see in your RV propane water heater.
• A blue flame signifies complete combustion, meaning the propane is fully burning with minimal byproducts, which is ideal for both efficiency and safety.

Yellow or Orange Flame

• A yellow or orange flame often indicates incomplete combustion. This can be caused by a lack of air (oxygen) in the burner, leading to inefficient fuel use and the production of carbon monoxide, a dangerous gas.
• Dirty Burner or Orifice: The burner or orifice may be dirty or clogged, restricting the airflow and causing the flame to burn yellow or orange.

Flickering or Unstable Flame

• If the flame is flickering or appears unstable, it might indicate drafts or issues with airflow around the burner.
• Unstable flames can also result from inconsistent gas pressure. This might be due to issues with the propane regulator or the gas line.

Possible Causes of Popping Noises

1. Sediment Buildup: Over time, minerals in the water can settle at the bottom of the water heater tank, forming a layer of sediment. When the heater is in operation, water trapped beneath this sediment layer can overheat and create steam bubbles. These bubbles rise through the sediment, causing popping or rumbling noises. Personally, I’ve heard this noise a few times, and they can be fixed by flushing out the tank. But, this wasn’t what I was hearing this time around.
2. Air in the Gas Line: Air trapped in the gas line can cause intermittent combustion, leading to popping noises. This can happen if the propane tank has recently been replaced or if there is a leak in the gas line. For my issue, this could be something to consider, just a few months prior to hearing these noises, I was dealing with a propane leak and I had the tank regulator replaced.
3. Dirty Burner or Orifice: A dirty burner or orifice can result in incomplete combustion, causing the propane to ignite irregularly. This can produce popping sounds and potentially affect the efficiency of the heater.
4. Water Expansion: As water heats up, it expands. In a closed system, this expansion can create pressure changes that might produce popping noises. This is more common in systems without an expansion tank or pressure relief valve.
5. Thermostat Issues: A malfunctioning thermostat can cause the water heater to overheat the water, leading to boiling and steam production, which can cause popping sounds.

After looking at my flame as it burns, I am pretty sure my first step will be to clean the burner and orifice, check for any obstructions like dust, dirt, or spider webs.

Troubleshooting Steps

1. Inspect for Sediment Buildup:
   • Turn off the Water Heater: Before inspecting, ensure the water heater is turned off and has cooled down.
   • Drain the Tank: Attach a hose to the drain valve and open it to drain the tank. Look for sediment in the water.
   • Flush the Tank: Use a flushing wand or simply refill and drain the tank multiple times to remove sediment.
2. Check the Gas Line:
   • Inspect for Leaks: Use a gas leak detector or soapy water to check for leaks in the gas line. Bubbles will indicate a leak.
   • Purge the Line: If air in the line is suspected, purge it by running the propane appliances until the popping noise subsides.
3. Clean the Burner and Orifice:
   • Turn off the Gas Supply: Ensure the gas supply is turned off before cleaning.
   • Remove the Burner Assembly: Consult your user manual for instructions on removing the burner.
   • Clean with a Brush: Use a soft brush to clean the burner and orifice, removing any debris or soot.
4. Test the Thermostat:
   • Check the Temperature Setting: Ensure the thermostat is set to the appropriate temperature (usually around 120°F to 140°F).
   • Test for Malfunction: If the thermostat seems faulty, consult a professional for testing and possible replacement.
5. Inspect for Water Expansion Issues:
   • Check for an Expansion Tank: If your system lacks an expansion tank, consider installing one to accommodate water expansion.
   • Inspect the Pressure Relief Valve: Ensure the pressure relief valve is functioning properly and releasing excess pressure.

Fixes for Common Issues

1. Sediment Removal:
   • Regularly flush your water heater tank to prevent sediment buildup. This can be done annually or more frequently if you notice popping noises.
2. Gas Line Maintenance:
   • Regularly inspect and maintain your gas lines to prevent air from entering the system. Replace any damaged lines and ensure connections are secure.
3. Burner and Orifice Cleaning:
   • Clean the burner and orifice periodically to ensure efficient combustion. This can be done as part of your regular RV maintenance routine.
4. Thermostat Replacement:
   • If the thermostat is faulty, replace it with a new one. This is a straightforward process, but if you’re unsure, it’s best to consult a professional.
5. Expansion Tank Installation:
   • Installing an expansion tank can help mitigate pressure changes due to water expansion, reducing the likelihood of popping noises.

Safety Tips

1. Regular Maintenance: Perform regular maintenance on your water heater to prevent issues from developing. This includes flushing the tank, cleaning the burner, and inspecting the gas line.
2. Monitor for Leaks: Regularly check for gas and water leaks. Use a gas leak detector or soapy water solution to identify gas leaks, and visually inspect for water leaks around the heater.
3. Follow Manufacturer’s Instructions: Always follow the manufacturer’s instructions for maintenance and repairs. This ensures that you are performing tasks correctly and safely.
4. Use Proper Tools: When performing maintenance, use the appropriate tools to avoid damaging components. If you’re unsure about any procedure, consult a professional.
5. Install a Carbon Monoxide Detector: Since propane combustion can produce carbon monoxide, it’s crucial to have a carbon monoxide detector installed in your RV to alert you to any dangerous levels of the gas.
6. Turn Off the Heater Before Maintenance: Always turn off the water heater and allow it to cool before performing any maintenance. This prevents burns and other injuries.
7. Consult a Professional: If you’re unsure about diagnosing or fixing an issue, it’s best to consult a professional. They can provide expert advice and ensure that repairs are done safely and correctly.

Conclusion

Popping noises in your Dometic RV propane water heater can be alarming, but they often have straightforward explanations and solutions. By understanding the possible causes, such as sediment buildup, air in the gas line, dirty burners, water expansion, and thermostat issues, you can take the necessary steps to troubleshoot and fix these problems. Regular maintenance and adherence to safety tips will help ensure that your water heater operates efficiently and safely, providing you with reliable hot water for your RV adventures.