If you own an RV, you know how important hot water can be on the road. Whether you need a warm shower after a long hike or just want to do the dishes, your Atwood RV water heater is essential. But, like all appliances, sometimes things go wrong. You turn on the tap and only cold water comes out. Or maybe you notice strange noises, leaks, or even odd smells. These problems can quickly ruin a good trip.
Understanding how to troubleshoot your Atwood RV water heater can save you time, money, and frustration. Instead of waiting for a repair shop or calling for help, you can solve many common issues yourself. This guide walks you through the most frequent problems, their causes, and step-by-step solutions.
Even if you’re not a technical expert, you’ll find clear explanations and practical tips to get your hot water flowing again.
How Atwood Rv Water Heaters Work
Before jumping into troubleshooting, it helps to know the basics. Most Atwood RV water heaters use either propane gas, electricity, or both. They usually hold 6 or 10 gallons of water. A thermostat keeps the water at the right temperature, while safety controls protect against overheating or gas leaks.
When you turn on the hot water tap, cold water enters the heater, pushing hot water out to your faucet. Inside, a burner (for gas) or a heating element (for electric) heats the water. The process is automatic, but several things can go wrong along the way.
Safety Tips Before You Start
Troubleshooting a water heater involves electricity, gas, and hot water. These can be dangerous if handled incorrectly.
- Turn off all power sources before working on the unit.
- Let the water cool down before touching any plumbing.
- If you smell gas, stop immediately and ventilate the area.
- Wear protective gloves and eye protection.
- If you’re not sure or feel unsafe, call a professional.
Credit: www.greggio.com
Common Problems And How To Fix Them
Below, we’ll look at the most frequent Atwood RV water heater issues, what causes them, and how to solve them.
1. No Hot Water
One of the most frustrating problems is getting only cold water. There are several reasons this can happen.
Possible Causes:
- No power (electric or gas)
- Faulty thermostat
- Burned out heating element
- Tripped circuit breaker
- Empty propane tank or closed valve
- Air in the gas line
Steps To Fix:
- Check the Power Supply: Make sure your RV is plugged in or the battery is charged. For electric models, check the circuit breaker or fuse.
- Inspect the Propane Supply: Open the propane valve and check that the tank isn’t empty. If your stove works on propane, the supply is likely fine.
- Reset the Water Heater: Look for a small reset button on the control board or behind the exterior access panel. Press it and listen for a click.
- Check the Thermostat: If you have a multimeter, test for continuity. Replace if faulty.
- Purge Air from the Gas Line: Turn on a stove burner to let air escape. Sometimes, a new propane tank or a long period of inactivity allows air to enter the system.
- Test the Heating Element: For electric models, use a multimeter to test the element’s resistance. Replace if there’s no continuity.
Non-obvious Insight: Many people forget about air in the gas line after swapping tanks. Always purge air by running a stove burner for a minute before troubleshooting the heater.
2. Water Heater Won’t Ignite (gas Models)
If your Atwood water heater won’t light, you’ll notice no flame and cold water. The “DSI” (Direct Spark Ignition) models are common and have electronic ignition.
Possible Causes:
- Faulty ignitor or electrode
- No spark (control board issue)
- Dirty burner or orifice
- Weak 12V battery (not enough power for the control board)
- Bad gas valve
Steps To Fix:
- Listen for Clicking: When you turn on the heater, you should hear a clicking sound. If not, check the 12V supply and fuses.
- Check the Electrode: Open the exterior panel. The electrode should be clean and close to the burner. Clean with sandpaper if dirty.
- Inspect the Burner Tube: Remove and clean any spider webs, dirt, or rust.
- Check for Gas Flow: Carefully loosen the gas line to the heater and check for gas (do this only if you are comfortable and it’s safe).
- Test the Control Board: If you have a spare, swap the board. These can fail, especially after lightning or power surges.
- Replace the Ignitor: If the electrode is damaged or the spark is weak, replace it.
Practical Example: If your RV sat unused for months, spiders love to build webs in the burner tube. Cleaning the tube often restores normal operation.
3. Water Is Too Hot Or Too Cold
Sometimes the water is scalding hot or barely warm. This usually points to a thermostat or ECO (Energy Cut Off) problem.
Possible Causes:
- Faulty thermostat
- Bad ECO switch (over-temperature switch)
- Thermostat not making good contact with tank
- Incorrect thermostat setting (if adjustable)
Steps To Fix:
- Check Thermostat Placement: The thermostat should be pressed flat against the tank. If it’s loose, reattach with thermal paste or new clips.
- Test Thermostat and ECO: With a multimeter, check for continuity. Replace both if either is faulty. They are often sold together.
- Replace if Needed: These are inexpensive and easy to swap.
- Check for Debris: Sometimes, debris between the thermostat and tank can cause poor readings.
Non-obvious Insight: On Atwood models, the ECO and thermostat are often mounted together outside the tank, not inside. Check both, as they work as a safety pair.
4. Water Heater Leaks
Leaks can be minor (just a drip) or major (flooding your RV). Catching them early saves money and damage.
Possible Causes:
- Loose drain plug or anode rod
- Cracked tank from freezing
- Bad gasket or O-ring
- Split water line
Steps To Fix:
- Check the Drain Plug: Tighten gently, but don’t overtighten as the tank is aluminum. Replace the O-ring if damaged.
- Inspect for Cracks: If you left water in the heater during freezing weather, the tank may crack. Replacement is the only fix here.
- Check Fittings and Hoses: Tighten any loose connections with a wrench.
- Replace Gaskets: On electric models, the heating element has a rubber gasket. Replace if you see drips around the element.
Practical Tip: Always drain your water heater before winter. Even a little water can freeze, expand, and crack the tank.
5. Smelly Or Discolored Water
If your hot water smells like rotten eggs or is rusty, it’s time to clean the tank.
Possible Causes:
- Bacteria (often from sitting water)
- Anode rod gone or worn out
- Rust inside the tank
Steps To Fix:
- Flush the Tank: Open the drain plug and run water until clear. Use a tank wand for stubborn sediment.
- Replace the Anode Rod: Atwood tanks are usually aluminum and don’t need an anode, but some models have one. Check and replace if over 75% worn.
- Sanitize the System: Mix one cup of bleach per 10 gallons of water, fill the tank, let sit overnight, then flush thoroughly.
Non-obvious Insight: Even aluminum tanks can develop bacteria if left full and unused. Sanitizing once a year prevents odors.
6. Burner Makes Popping Or Roaring Noise
A loud burner is not normal and signals incomplete combustion.
Possible Causes:
- Dirty burner or orifice
- Incorrect air/gas mixture
- Debris in the burner tube
Steps To Fix:
- Clean Burner Assembly: Remove and brush out dirt, rust, or spider webs.
- Adjust Air Shutter: Slide the air shutter to change the mix. The flame should be blue with minimal yellow.
- Check for Blockages: Look for insects or soot in the tube.
Practical Example: If the burner pops every few seconds, it’s almost always a sign of a dirty burner tube or wrong air setting.
7. Water Heater Turns Off Randomly
Does your water heater shut off before the water is hot? This is usually a safety feature, but sometimes it points to other issues.
Possible Causes:
- Overheating (bad thermostat or ECO)
- Weak flame (not heating fast enough)
- Low voltage on control board
- Faulty circuit board
Steps To Fix:
- Test Voltage: Use a multimeter to check for 12V at the control board.
- Check Thermostat/ECO: Replace if they trip too soon.
- Clean Burner: Weak or yellow flames can cause the unit to shut down early.
- Replace Circuit Board: If all else fails, the board may be faulty.
Non-obvious Insight: Low battery voltage can cause the control board to behave unpredictably, shutting down the heater even if everything else is fine.
8. Electric Mode Not Working (dual-fuel Models)
Many Atwood heaters can use both gas and electric. Sometimes, electric mode fails while gas works fine.
Possible Causes:
- Tripped breaker or blown fuse
- Burned out heating element
- Loose or corroded wiring
- Faulty electric thermostat
Steps To Fix:
- Check Breakers and Fuses: Reset any tripped breakers and replace blown fuses.
- Test Heating Element: With power off, use a multimeter. Elements usually read 10-20 ohms.
- Inspect Wiring: Look for loose or corroded connections. Clean and tighten.
- Test Electric Thermostat: Replace if not working.
Practical Tip: Water heaters often have a hidden fuse or breaker near the unit itself, separate from the main panel.
9. Pilot Light Won’t Stay Lit (manual Models)
Older Atwood models have a manual pilot. If the light goes out, you get no hot water.
Possible Causes:
- Bad thermocouple
- Dirty pilot orifice
- Weak gas supply
Steps To Fix:
- Hold the Pilot Knob: Hold the knob longer (30-60 seconds) to heat the thermocouple.
- Clean the Orifice: Use compressed air to remove dust.
- Replace Thermocouple: If it won’t stay lit, swap for a new one.
Non-obvious Insight: Thermocouples wear out faster if the pilot is left running all season. Turn off when not in use.
10. Water Heater Won’t Drain
If you can’t get water out when draining, sediment or a clogged plug is likely.
Possible Causes:
- Clogged drain plug
- Heavy sediment inside tank
Steps To Fix:
- Remove Drain Plug: Use pliers if it’s stuck, but avoid damaging threads.
- Flush with Pressure: Use a tank flushing wand or a garden hose.
- Repeat Annually: Prevents buildup and extends heater life.
Practical Tip: Always release water pressure before removing the plug, or you’ll get soaked.
11. Fault Codes And Error Lights
Modern Atwood heaters have error codes or blinking lights.
Common Codes:
- 3 flashes: Ignition failure
- 4 flashes: High temperature limit exceeded
- 5 flashes: Faulty thermostat
Steps To Fix:
- Count the Blinks: Turn on the unit and watch the light.
- Consult Manual: Each code means something specific. Download the manual from the Atwood website if lost.
- Address the Issue: Follow steps above for ignition, thermostat, or temperature issues.
Non-obvious Insight: Some codes clear themselves after fixing the problem, but others require a manual reset.
12. Low Hot Water Pressure
If your hot water trickles but cold is fine, the cause is often at the heater.
Possible Causes:
- Clogged check valve
- Mineral buildup inside tank
- Kinked or pinched water line
Steps To Fix:
- Check Check Valve: This is a one-way valve at the heater’s hot water outlet. Remove and clean or replace if stuck.
- Flush the Tank: Remove sediment as above.
- Inspect Lines: Straighten any pinched hoses.
13. Water Too Hot In Shower, But Not At Sink
This uneven temperature is often a mixing valve issue.
Possible Causes:
- Bad mixing valve (on some RVs)
- Long pipe runs (heat loss in lines)
- Cross-connected plumbing
Steps To Fix:
- Check for Mixing Valve: Some RVs have a valve that blends hot and cold. Replace if faulty.
- Insulate Pipes: Reduces heat loss.
- Check Plumbing Layout: Look for crossed lines that could dilute hot water.
14. Water Heater Won’t Turn On
If the unit is dead, nothing works.
Possible Causes:
- No 12V or 120V power
- Blown fuse or tripped breaker
- Faulty ON/OFF switch
- Broken wiring
Steps To Fix:
- Test Power at Heater: Use a multimeter at the heater’s terminals.
- Check Switches: Some models have more than one ON/OFF switch (inside and outside).
- Replace Fuses/Reset Breakers: Always use the correct size.
15. Soot On Exterior Vent
Black soot means poor combustion.
Possible Causes:
- Dirty burner or orifice
- Too much gas, not enough air
- Insect nests
Steps To Fix:
- Clean Burner and Orifice: Remove and clean parts.
- Adjust Air Shutter: Increase air for a blue flame.
- Check for Nests: Insects love the warm, dark vent.
Atwood Rv Water Heater Troubleshooting Table
To make things clearer, here’s a quick reference comparing common problems, causes, and solutions:
| Problem | Possible Cause | Action |
|---|---|---|
| No hot water | No power, empty propane, thermostat | Check power, gas, thermostat, reset |
| Won’t ignite | Ignitor, control board, dirty burner | Clean, test, replace parts as needed |
| Leaks | Loose plug, cracked tank, bad gasket | Tighten, replace O-ring, check tank |
| Smelly water | Bacteria, old anode, rust | Flush, sanitize, replace anode |
| Low pressure | Clogged valve, sediment | Clean valve, flush tank |
Credit: anniesdeli.com
Atwood Water Heater Vs. Other Brands
Wondering How Atwood Compares To Other Rv Water Heaters?
| Feature | Atwood | Suburban | Girard (Tankless) |
|---|---|---|---|
| Tank Material | Aluminum | Steel (w/anode) | No tank |
| Weight | Lighter | Heavier | Lightest |
| Maintenance | Less (no anode) | More (anode replaces) | Least |
| Heating Method | Gas/Electric | Gas/Electric | Instant Gas/Electric |
Non-obvious Insight: Atwood’s aluminum tanks mean you rarely need an anode rod, unlike Suburban’s steel tanks. But aluminum is more likely to crack if not winterized properly.
Maintenance Tips For Long Life
Regular care prevents most problems and extends your heater’s life.
- Drain and flush the tank every season.
- Clean the burner and vent at least once a year.
- Test the thermostat and ECO before long trips.
- Inspect wiring and fuses for corrosion.
- Sanitize the tank if the RV sits unused for months.
- Winterize by draining all water before freezing weather.
- Check for leaks after every move.
Practical Example: One RV owner found a leak after driving over rough roads. Shaking can loosen fittings, so check connections before and after trips.
Credit: smartmonkeylab.pl
When To Call A Professional
Some issues require special tools or experience:
- Major electrical repairs
- Gas valve replacement
- Tank replacement (cracked tanks)
- Repeated error codes not solved by basic troubleshooting
If you’re ever unsure, it’s safer to call an RV technician. Mistakes with gas or electric systems can be dangerous.
Useful Resources
For more details, the official manufacturer’s resources are always a safe bet. The Dometic (Atwood) website offers manuals, parts lists, and troubleshooting guides.
Frequently Asked Questions
What Size Socket Do I Need To Remove The Atwood Drain Plug?
Most Atwood water heaters use a 1-1/16″ socket for the drain plug. Always use the correct size to avoid stripping the plug.
Why Does My Atwood Water Heater Keep Tripping The Breaker?
A breaker that trips often means a shorted heating element, bad wiring, or overloaded circuit. Test the element with a multimeter and inspect all connections.
How Often Should I Flush My Atwood Water Heater?
Flush at least once per season, or more often if you use hard water. Regular flushing removes sediment and keeps the heater working efficiently.
Can I Run My Atwood Rv Water Heater On Both Gas And Electric At The Same Time?
Yes, most dual-mode models allow you to run both for faster heating. Check your manual to confirm, as some older models do not support this.
What Should I Do If My Atwood Water Heater Makes A Whistling Noise?
A whistling sound often means restricted water flow or pressure issues. Check for a clogged check valve, kinked line, or sediment in the tank.
—
With a little knowledge and regular care, your Atwood RV water heater can provide reliable hot water for years. Troubleshooting might seem complicated, but most issues are simple to diagnose and fix. Remember, safety always comes first, and if you’re ever unsure, don’t hesitate to get professional help. Safe travels and enjoy your adventures—one hot shower at a time!