ServiceNomad RV · Knowledge
Atwood Water Heater Not Heating
Atwood water heaters are the other major brand in RVs, and they differ from Suburban models in several ways—most notably, Atwood heaters often have both gas and electric heating elements. When an Atwood water heater stops heating, the troubleshooting approach depends on whether you're trying to heat with gas, electric, or both. Understanding how each mode works helps you narrow down the issue quickly.
Gas Mode vs Electric Mode Operation
Most Atwood water heaters have two heating methods: a propane-fired burner (similar to Suburban) and a 120V electric heating element (like a household water heater). These two systems operate independently—the control board or switch panel allows you to select gas only, electric only, or both simultaneously (fastest heating). Troubleshooting requires determining which mode is failing. If the water heater works on electric but not gas, the issue is with the propane burner, ignition system, or gas supply. If it works on gas but not electric, the problem is with the heating element, circuit breaker, or 120V wiring. If neither mode works, suspect a shared component like the thermostat or a complete loss of power to the unit.
Gas Burner Ignition and Flame Sensor
Atwood gas burners use either a spark igniter or electronic ignition module (depending on model year). The ignition sequence is similar to Suburban furnaces: the control board attempts ignition, monitors for flame via a sensor, and either continues operation or locks out. Common gas-mode failures include a failed igniter, dirty flame sensor, restricted burner orifice, or low gas pressure. A technician will verify propane supply, test the igniter for spark (or glow in the case of direct-spark ignition), clean the flame sensor, and inspect the burner for debris or carbon buildup. Atwood burners are prone to carbon buildup if operated at high altitude without jet adjustment.
Electric Heating Element Failures
The electric heating element in an Atwood water heater is a resistive coil immersed in the water tank. Over time, these elements can burn out (open circuit), develop mineral scale buildup that insulates them from the water, or corrode through if the anode rod has depleted. A failed element will not heat the water even though the switch is on and the indicator light (if equipped) may illuminate. A technician will test the element with a multimeter—typical resistance is 10-16 ohms depending on wattage (1400W or 1650W). Infinite resistance means the element is open and needs replacement. They'll also check the high-limit thermostat, which can trip if the tank overheats and must be manually reset.
Control Board and Thermostat Issues
Atwood water heaters use electronic control boards (on newer models) or mechanical thermostats (on older models) to regulate water temperature. If the control board fails, neither gas nor electric mode will heat properly. The board may display error codes (on digital models) or simply stop responding to input. Common control board issues include failed relays (that switch gas valve or electric element power), voltage supply problems (check for 12V DC and 120V AC at the board), or corrosion on circuit traces from moisture intrusion. A technician will test voltages and inspect the board for visible damage before replacing it.
⚠️ Safety Notes
- Always turn off 120V power and propane supply before working on or inside the water heater—both electric shock and gas leak risks exist.
- If the tank is hot but no hot water comes out, the dip tube may have failed—this is a separate plumbing issue requiring tank access.
💡 Prevention Tips
- Replace the anode rod every 1-2 years to prevent tank corrosion and extend water heater life.
- Drain and flush the tank annually to remove sediment and mineral buildup that can damage the electric element.
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