Atwood RV Water Heater Troubleshooting
The Short Answer: An Atwood (now Dometic) 6- or 10-gallon RV heater is two machines in one box: LP DSI and a 120-volt element. Name which half is dead, prove the tank is full, set bypass to normal, then reset the ECO once. Click-no-light is Atwood clicking. Electric dead with gas fine is Atwood electric. Do not keep sparking into a propane smell.
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Search Intent & The Real Problem
The interior switch is on. The shower lasts forty seconds, or the tank is silent. People buy a “new water heater” because they never split the fuels. Gas and electric are independent. Winterize is the usual crime: empty tank, electric on, ECO open, maybe a cooked element. Bypass valves left in bypass means the tank never fills and both fuels fail or dry-fire.
Suburban SW10DE / Phase 3 is a different board and a different ECO — SW10DE, Phase 3, Suburban RV reset. Wrong parts melt the harness.
What other guides get wrong
They reprint a 40-gallon house-tank article onto a 6-gallon Atwood. There is no standing pilot on DSI models. They mix Suburban Phase 3 boards with Dometic. And they skip the three-valve bypass, so you “troubleshoot” a tank that has no water in it.
Step-by-Step Troubleshooting
Step 1: Identify the heater and prove it has water
- What to look for: Atwood / Dometic on the door — G6, GC6, G10, GC10, WH-6, WH-10 and similar 6- and 10-gallon boxes. Three-valve bypass in the heat path, not winterize. Open a hot faucet until you get a steady stream, no sputter. Residual water in the lines is not a full tank.
- Required tools: Flashlight, the plumbing diagram in the cabinet.
Electric switch off until the tank is full so you do not dry-fire the ~1400 W element.
Step 2: Decision tree — which half is dead?
| What works | What failed | Go here |
|---|---|---|
| Gas heats, electric does not | 120 V, ECO, element, interior electric switch | Electric not working |
| Electric heats, gas clicks or is silent | LP, DSI board, igniter, solenoid, gas ECO | Clicking but not lighting |
| Both dead | Bypass, empty tank, both ECOs, no 12 V / no 120 V | Stay on this page, Steps 3–4 |
| Neither switch does anything | Coach power, fuse, interior switch | 12 V at the board, 120 V at the pedestal |
| Water in the bay | Tank, element threads, drain plug, pressure-relief | Isolate; leaking shell is replacement |
- What to look for: One working fuel proves the tank can hold water. Diagnose the dead fuel. Both dead is water or power, not two coincidental parts.
- Required tools: Ears at the exterior door (click vs silence), a nearby 120 V outlet as a sanity check.
Step 3: Bypass, bottles, and coach power
- What to look for: Bypass valves pointing around the tank. LP bottles open, pigtail not stripped, stove lights (stove works + Atwood silent = problem at the heater; nothing LP lights = supply). Shore-power pedestal or generator actually putting out 120 V; bathroom GFCI tripped. Interior 12 V switch illuminated.
- Required tools: Eyes. Receptacle tester. No wrenches on LP flares.
Air after a bottle swap can delay ignition. Loosening flares is how bays fill with gas.
Step 4: ECO reset — once, tank full, power off
- What to look for: Red or black reset on the thermostat/ECO behind the exterior door, on the tank jacket. Dry camp, winterize, or electric on with bypass open almost always leaves this open. Gas DSI lockout is often a switch cycle, not that same button — see the clicking article.
- Required tools: Finger. Tank full. Shore power off, then on after the click.
Reset once. If it opens again in minutes, the thermostat is welded, the element is grounded, or you still have no water. Do not hold the button in. Never jumper it.
Step 5: Stop before you buy a board
- What to look for: Spark with bottles closed before you condemn a DSI board. 120 V at the heater before you buy an element. A Suburban-shaped door on an Atwood bay — SW10DE / Phase 3, not a Dometic board. Heat-discolored wiring is a tech, not a YouTube element swap.
- Required tools: The model on the rating plate for parts. Multimeter only with power verified dead.
Element ohms on these 120 V ~1400 W units are not the house-tank 12–13 Ω figure (that is 4500 W / 240 V). Infinite or short-to-tank with power dead is still a bad element.
When DIY Ends: Calling a Licensed Pro
Stop at gas-solenoid or board replacement, LP odor, an ECO that will not latch, a leaking tank into the bay, or a pedestal that trips when the element kicks in. You may fill the tank, set bypass, confirm 12 V / 120 V, verify spark with fuel off, and reset one ECO on a full tank. Dometic/Atwood boards and valves are model-specific. A mobile RV tech is cheaper than a coach fire from a fifth ignition trial.
Frequently Asked Questions
Q: Why is my Atwood RV water heater not working? A: Empty tank or bypass, a tripped ECO, no 120 V on electric, or DSI/LP failure on gas. Split the fuels. One working side means the tank can hold water.
Q: Should I reset an Atwood if both gas and electric are dead? A: Fill the tank first, bypass off, then reset the ECO once. Resetting dry is how the element dies. If it trips again, stop and hire an RV tech.
Q: Is an Atwood the same as a Suburban SW10DE? A: No. Different DSI boards, ECOs, and parts. Use the rating plate. Suburban paths: SW10DE and Phase 3.