RV Water Heater Not Working on Electric

The Short Answer: When an RV water heater still heats on propane but not on electric, the cause is usually on the 120-volt side: the separate electric switch is off, the coach has no shore or generator power, the water heater breaker has tripped, or the high-temperature limit (ECO) has opened. That last one often happens after the element was switched on with an empty or bypassed tank.

First, identify the appliance, not the coach

The RV builder does not make the water heater. Open the exterior water heater door and read the label on the appliance. Most dual-fuel tank heaters in North American RVs are Suburban or Atwood (now Dometic). The model number tells you whether an electric element is fitted at all. On Suburban models, an “E” in the suffix (SW6DE, SW10DEL and so on) means an electric element is fitted. A plain “D” model is propane-only.

If the label says Girard, Truma or Furrion and the unit is an on-demand (tankless) heater, this page does not apply. These units are usually propane-fired with a 12-volt control. Truma, for example, lists the AquaGo comfort plus (opens in a new tab) as propane with a 12 V DC supply. For on-demand units, use the RV water heater troubleshooting hub instead.

Why gas can work while electric does not

The propane burner and the 120-volt element share the tank but have their own switch, thermostat and high-temperature limit. Suburban’s installation and operation manual (opens in a new tab) describes two separate limits on its DE models: one for the 12-volt gas control and one for the 120-volt element. A tripped electric limit therefore leaves gas heating untouched, and a hot tank on propane tells you nothing about the element.

Suburban rates the element on its current DE and DEL heaters at 1,440 watts. The wiring diagram in its manual shows about 12 amps at 120 volts. Suburban’s 2025 catalog (opens in a new tab) gives an electric-only recovery of 6 gallons per hour, compared with 16.2 gallons per hour on electric and propane together. Slow heating on electric alone is normal; no heat at all is not. For Atwood or Dometic wattage, read the rating plate.

Where the electric switch is

Many owners miss this one. The switch on the wall inside the coach does not always control the element:

• Suburban DE models: the catalog says the interior switch operates propane only. The element has its own on/off switch on the heater housing, behind the exterior door at the lower left of the control area.
• Suburban DEL models: the interior switch controls both propane and electric, and there is also an on/off switch on the heater housing. Both must be on.
• Atwood/Dometic combination models: Dometic’s manual (opens in a new tab) places the electric switch at the rear of the water heater. Some RV builders also fit a remote switch inside the coach.

Coach wiring varies, so check your RV’s documentation if the switch is not where you expect.

What you can check safely

Work through these in order with the electric switch off:

1. Confirm 120-volt power. The coach must be plugged in to a live pedestal or running the generator. Check whether other 120-volt outlets and appliances work. The batteries and inverter do not run a standard element unless the coach was built to do that.
2. Check the coach’s breaker panel. Find the breaker labeled for the water heater. If it has tripped, reset it once. If it trips again, leave it off.
3. Look for a tripped GFCI. In some coaches, outlets and circuits share ground-fault protection. If nearby outlets are dead too, reset the GFCI outlet once.
4. Put the bypass valves in normal position. After winterizing, the bypass valves are often left in bypass, which keeps water out of the tank. Return them to normal (heater in service) according to your coach’s plumbing label.
5. Fill the tank completely. With water pressure on, open a hot faucet and let it run until you get a steady stream with no spitting air. Suburban warns that even brief operation of the element without water will burn it out. Dometic warns that turning on power before water covers the element may burn it out and void the warranty. If this may already have happened, read what to do after a water heater was turned on without water.
6. Switch electric on and wait. On electric alone, a 6-gallon tank takes roughly an hour.

The high-temperature limit (ECO)

If power is present and the tank is full but there is still no heat, the 120-volt high limit may have opened.

Suburban. The manual says the electric limit trips above 180°F. It sits under a rubber grommet behind the “PUSH TO RESET” cover, and is reset by pressing that grommet only after the water has cooled below 110°F. The cover stays on; the button is not visible and is pressed through the rubber. Press once. If it trips again, the limit is doing its job and the cause needs a technician. Our guide on how to reset a Suburban water heater covers both limits.

A red light is not the electric limit. On Suburban switch plates, the red “RESET” light shows a gas ignition lockout. It does not indicate an electric fault.

Atwood/Dometic. The manual describes a manual-reset high-temperature limit at the rear of the heater, next to the electric connections. Reaching it often means removing an interior access panel near 120-volt wiring. If that is the case on your coach, leave the reset to a technician. A limit that opens again needs diagnosis, not more resets.

What the symptoms usually point to

What the technician will check

With power isolated, an RV technician confirms that 120 volts reaches the heater and passes through the switch. They test the electric thermostat and high limit, and check the element for an open circuit or a short to the tank. Replacing an element means draining the tank, and on Atwood/Dometic heaters access to the rear can mean removing an inside panel. Dometic’s manual warns against aftermarket add-on heating elements, which can lack the factory parts’ safety controls and void the warranty; replacement parts should be the ones listed for the model on the label.

Frequently Asked Questions

Q: Why does my RV water heater work on propane but not on electric? A: The two heat sources share a tank but have separate switches, thermostats and high limits. Gas heating proves only that the tank holds water. Check the electric switch, 120-volt power, the water heater breaker and the bypass valves before suspecting the element.

Q: I turned on the interior switch. Why is the electric side still off? A: On Suburban DE models, Suburban says the interior switch controls propane only; the element has its own switch on the heater housing behind the outside door. On DEL models, both switches must be on. Atwood/Dometic combination models have the electric switch at the rear of the heater.

Q: Can I run electric and propane at the same time? A: On Suburban heaters fitted with an element, yes. Suburban’s catalog lists a faster combined recovery rate than electric alone. Check your own heater’s manual for other brands.