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Atwood RV Water Heater Troubleshooting Guide

Atwood is one of the most well-known manufacturers of gas and gas/electric water heaters in the RV circuit. They’re known for their quality and longevity, and are considered a trusted brand. As with anything in your RV, however, it requires regular maintenance and upkeep. 

Failing to keep an eye on your Atwood RV water heater can lead to spotty performance down the line. You don’t want to be left without hot water, especially if you live in your RV full time. If you have encountered some issues with your water heater, there are a few troubleshooting tips that can diagnose and fix the problem. 

Troubleshooting your Atwood RV water heater is relatively simple. If the heater won’t stay lit, you could have a defective thermostatic control. If the heater has no hot water, make sure the issue is not with an electric breaker, and check the bypass valve. When the gas burner is not igniting, survey the heater for loose wires or rust. 

Atwood RV Water Heater Troubleshooting Guide 

There are a number of issues you might encounter as the owner of an Atwood RV water heater. The entire water system in your RV is complex, and requires many moving parts to work correctly.  Having a few tricks up your sleeve of how to troubleshoot your water heater will keep you from needing expensive repairs later. 

Atwood Water Heater Has No Hot Water 

The primary, expected job of a water heater is, of course, to heat water. If you find that your Atwood water heater isn’t heating water, there are steps you can take to find the root of the issue: 

Check The Breakers 

If you have an electric water heater, first check to see if it hasn’t shorted out. Check the breaker to see if it’s tripped in the fuse box. If you discover a blown fuse, you may need to replace it. This may be a good time to take a look at all of the fuses in your box to double-check that everything is in working order.  

Replacement fuses are relatively inexpensive and can be easily installed. You can usually find them in sets that are color-coded for easy identification. 

Check The U-Tube

Has the U-Tube been blocked? This is a common problem that could be keeping the water from heating adequately. If you see any blockages, clean it out immediately. This will ensure that the connection from the burner is adequate. Many common issues with Atwood RV water heaters stem from a blocked u-tube. 

Check The Bypass Valve

Now, take a look at the bypass valve if there wasn’t anything wrong with the fuses or breakers. The purpose of the bypass valve is to get the heater prepared for winter; you might need to switch it off in warmer weather. This could solve the problem. 

While you’re checking the bypass valve, take a look at the handle of the bypass valve line. If the valve has been left open, the water is being sent past the heater. This will result in no hot water going through. Close the valve, disengaging the bypass. 

Check The Faucets 

See if you’ve got any faucets that have been left open. Multiple open faucets might be too much for smaller heater models to handle. They won’t be able to send hot water to both. What you’ll end up with is hot water coming from one and cold water from another. 

Check The Temperature Selector 

Your temperature selector could be the culprit in an Atwood water heater that has no hot water. See where the selector is set, and try resetting it. 

Some Atwood thermostats are not adjustable, and are fixed at 140 degrees. This will depend heavily on the year and model of your water heater. If you have a “snap disc” thermostat, it will open at 140 and close at 110 for a heating cycle. Usually, if you know your model was made after 2004, you might have one that is adjustable. 

Check The Position Of The Thermostat

The thermostat for your water heater should be making direct contact with the aluminum tank. This ensures that it will correctly monitor temperature, and can cause issues if it has been misaligned. It should be set at the HI position, and heat the water at 130-140 degrees, depending on your heater. 

If you find that it is defective, you’ll have to replace it. You may be able to do this yourself, or you can find a skilled repair specialist who can get the job done. 

Atwood Water Heater Won’t Stay Lit 

If you find that your water heater does not keep a continuous light, the trouble could be a defective thermostatic control or thermocouple. The best way to troubleshoot it is to monitor the signal from the thermocouple. 

Check The Thermocouple 

As a complex part with a lot of different elements, there are a few things that could be causing your thermocouple to malfunction. When you check the thermocouple, there are a few places you should look first. 

Step One

First, you’ll want to hold the knob longer when you’re turning it on. It may take a bit more time for the gas valve or electric board to get the signal from the thermocouple. This indicates that a flame is present. 

Step Two 

Then, ensure that the pilot flame is clean before repositioning so that it is touching the end of the thermocouple probe. The trouble may just be that the pilot flame is poor, or not appropriately established. In this case, clean or replace the orifice. 

Your thermocouple should be set so that it’s sitting just above the pilot flame, and that they’re just in contact with each other. 

Step Three

Check the thermostatic controls next. It is part of the gas valve assembly, and it has a dial that allows for temperature adjustments. It also monitors your water temperature and keeps it from reaching dangerous levels. 

If you find that the thermocouple is just loose, you can tighten the connection at the gas control. Wait until it is not hot anymore to reposition it to better contact the pilot flame. 

If the pilot outage won’t stay lit, or the thermocouple is weak, it is defective and may need to be replaced. It is best that you get this replaced by an experienced, trained gas technician. It can be very dangerous to attempt this replacement on your own. 

Check The U-Tube 

Once again, an obstruction in the u-tube could be to blame for your Atwood water heater not staying lit. Inspect it and clear out any debris you may find. 

Check The Pressure Reading 

An incorrect gas pressure reading could result in your Atwood water heater snuffing out too soon. Check to see if the gas pressure reading is correct by referencing the instructions in the manufacturer’s manual. In an Atwood model, you’ll want to adjust the pressure to a minimum of 11” W.C. 

Atwood Water Heater Has No Spark On The Electrodes

Electrodes are the components that supply power to the anode rods. The anode rods keep the inside of the water heater from getting rusty, thus prolonging their lifespan. When the electrodes seem to have lost their spark, here is some troubleshooting advice for how to diagnose and fix the issue: 

Check For Overlapping 

One cause of the problem may be an overlap in the electrodes. Carefully reposition the electrodes, working slowly and with a steady hand. Ideally, you should aim for roughly one inch of space between each one. 

Check The Connection 

The connection between the primary burner and the electrodes should be strong. If it seems loose, use a screwdriver to tighten the screws that hold the electrodes to the main burner. Try out the water heater again and see if this might have fixed the issue. 

If you didn’t find a loose connection on the burner, try the circuit board. There may be a loose connection there. Depending on how loose it may be, you could secure it yourself. Though, take caution and only do so if you’re confident in your abilities. 

If it seems the circuit board is unresponsive, you may need to replace the entire thing. 

Clean The Electrodes

Dirty electrodes will become faulty and damaged over time. They can accumulate mildew, dust, and dirt over time, and should be maintained properly. If they’ve gotten dirty and cannot conduct electricity properly, clean them off. You can use a microfiber cloth for this. 

Atwood RV Water Heater Leaking From The Relief Valve 

If you notice dripping from an Atwood RV water heater, it may not actually be a huge issue. Occasional drips are just a product of the water needing to go somewhere when it expands in a closed system. This is normal and not cause for concern. 

If you do want to mitigate it, set a small container there to collect the water. Dump it frequently to keep from it from overflowing, and it will prevent water from settling into your floor. The amount that drips might not even be significant enough to warrant this. 

However, if dripping is very frequent, or if you see a significant leak, there might not be enough of an air pocket to allow for expansion. All you need to do is create that pocket, and you shoul be able to avoid future leaks. 

To Repair A Leak In An Atwood RV Water Heater Relief Valve 

  1. Turn off the RV water heater entirely, and turn off the cold water supply.
  2. Open the tap in your RV as you normally would. 
  3. Allow the water to flow out through the pressure relief valve until it stops. 
  4. Once the water has completely finished running, you can release the valve handle. 
  5. An air pocket will develop as you watch the cold water fill the tank. This is a process you should revisit regularly. It will keep the space open for the water to expand and contract. 

However, if you try to create an air pocket and still have an issue with the relief valve leaking, you might need to install an expansion tank. They’re designed to handle the extra space that the water needs without forcing it out of the valve. 

Atwood Water Heater Has A Rotten Egg Smell 

Unpleasant smells can be the worst in an RV, especially the strong odor of rotten eggs. When you detect a rotten egg smell coming from your Atwood RV water heater, you might be tempted to replace it. 

Thankfully, there’s no need for such drastic measures. Atwood water heaters have a protective coating on the inside of their tanks. This coating is meant to prevent corrosion, much the way the anode rod keeps away rust. 

When the coating fights back against corrosion, hydrogen is released into the water. When the hydrogen mixes with sulfur and creates hydrogen sulfide. The result is a stinky, sulfurous rotten-egg odor. 

The anode rod could also deteriorate as it is used, which will release sediments into the tank. Bacteria mixes with the water and produces a foul rotten egg scent within an Atwood RV water heater. 

The solution to the foul odors is to flush your tank. This should be done regularly so that the scent doesn’t have time to build up. 

How To Flush An Atwood RV Water Heater: 

  1. First, you’ll want to drain the tank. There should be a drain plug somewhere on your water heater. Upon opening it, water should rush out without obstruction and drain the tank. 
    1. If you find that it isn’t draining easily, open up the temperature valve and the pressure valve. You might need to feel around in them with a flexible wire to remove any debris. 
  2. Once it is empty, you’ll want to fill it back up with a solution of liquids that will clean it out. You can use household products like vinegar mixed with water, 3% hydrogen peroxide (a mixture of 1:160 hydrogen/water), chlorinated water, or a small amount of bleach mixed with warm water. 
  3. Allow your mixture to sit in the water heater for several hours. 
  4. Drain the mixture again, and then flush the system with plain water heavily. You will want to get rid of the taste of your mixture as much as possible. 

This should remove the foul odor from your water heater. If you flush it regularly, usually once every three or four months, you will avoid the scent in the future. 

Atwood RV Water Heater Gas Burner Will Not Ignite 

As opposed to lighting but not staying lit, you might notice that the gas burner is not igniting at all. This, of course, will prevent the water from heating whatsoever. In this case, there are elements you should give attention to that could fix the problem. 

If you see that your water burner has rust, however, you’ll just need to replace it. The rust has likely corroded it to the point where it can no longer function. 

Look For Loose Wires 

Loose wires in your water heater gas burner will keep the propane from igniting and heating the burner. Tightening them will help the gas flow steadily, and can prove to be a simple fix. 

Check for Clogs 

If your airline is clogged with dirt, dust, or soot, it will cause the gas burner to be unable to ignite. Clearing them out from there, as well as checking the u-tube for obstruction, may solve the problem. 

Not necessarily a clog in the traditional sense, but your airlines can also accumulate air. This is especially true if the Atwood water heater has been left out too long in storage. Allowing the excess trapped air to bleed out from the airline should allow the burner to ignite. 

Check The Flame Spreader 

The flame spreader can sometimes be knocked loose, especially from the motion of an RV. If it looks to have been jostled, simply slide it back into place. 

Atwood RV Water Heater Making Noises 

While your water heater might not be 100% silent, it still shouldn’t make popping or whistling noises. Before you head out on a long trip, keep an ear out for any of the following sounds: 

  • High-pitched or screeching sounds: High-pitched noises can be attributed to the buildup of limescale (or calcium) on the element. This could also be a sign of corrosion. 
  • Popping: Popping sounds are a product of mineral deposits that have taken hold and built up in the tank. This will impact both electrical and gas units. 
  • Whistling: If you hear whistling, you may have debris caught in your check valve. 

The best way to avoid these types of sounds in your Atwood RV water heater is to maintain and flush your water heater regularly. If it persists, you might need to replace the unit. 

Atwood RV Water Heater Keeps Resetting 

There are a few things that could cause your Atwood RV water heater to reset on its own. If it resets too frequently, you might have trouble getting it to do what you want when you actually need it to reset. 

The usual suspect that causes the water heater to continuously reset is an error with the thermostat, in either the upper or lower heating element. What might cause this include: 

  • The high-limit switch malfunctioning and overheating the water. 
  • A short in the heating element could also cause the water to overheat. 
  • The wiring in the heating element coming loose. While this could cause the reset switch to trip on its own, it could also prevent it from doing so at all. 
  • If you’ve experienced a power surge lately, this is another probable issue. Just as with loose wiring, this could either excessively trip the reset button, or keep it from resetting at all. 

To alleviate this, you might need to replace the thermostat, or at the very least repair the wiring. Consult your Atwood RV water heater owner’s manual for advice on the best course of action for your situation. 

Atwood RV Water Heater Building Up Soot 

When excess carbon monoxide mixes with the gasses in a water heater, soot is produced. Accumulated dirt and soot is not just unsightly, it can also lead to blockages. The blockage prevents carbon monoxide from flowing outward. 

If your set is sealed too tightly, it may be preventing enough oxygen from getting into the unit. Clean the soot away before you start your troubleshooting process. 

  1. If your gas tank is running on empty, you might be harboring more soot. Refill it and see if that solves the problem. 
  2. Check the U-tube, main burner, and exhaust grill for obstructions. Carefully clean them out to prevent further soot buildup. 
  3. If the main burner, air valve, air shutter, or flame spreader are misaligned, you might be harboring more soot. Keep an eye out for loose screws to tighten, and corrosion or limescale buildup to clean off. 

When To Call A Technician 

You might not be able to full diagnose what is causing your Atwood RV water heater to malfunction. In this case, you might want to call Atwood’s service line and describe the issue to them. They may be able to walk you through the process of fixing it yourself. 

If you don’t have the ability to fix something yourself, or even if you’re just not fully confident in your ability to do so, reach out. It’s always better to play it safe and entrust your water heater to a trained expert. 


Atwood RV water heaters can be reliable machines that will keep your RV’s water hot for years to come. Just like everything in your RV, though, it needs frequent maintenance and upkeep. 

To troubleshoot your Atwood RV water heater, keep an eye on the u-tube. Check the fuse boxes and burners for weak connections, tightening them as needed. If your water heater is producing a foul odor, try flushing it out with a solution of vinegar, chlorinated water, or water mixed with hydrogen peroxide. 

When in doubt, you can always call a mechanic to tend to your Atwood water heater. However, if you keep it well maintained, you will run into fewer problems in your RV. 

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