How To Turn on the Water Heater in Your RV

Contributor

Tucker Ballister

Favorite Trip

5 Months Solo on the Road

Home Base

Hendersonville, NC

Favorite RV

2008 Fleetwood Bounder

About Contributor

Tucker Ballister is our Content Strategist. He’s a lover of the open road and the proud owner of a 2021 Sunlite Classic travel trailer (his 3rd RV to date). Check out more of his RV adventures, gear reviews, and outdoor advice at thebackpackguide.com.

Easy access to hot water is one of the most convenient benefits of RV living. Coveted by primitive tent campers, you won’t want to go without access once you’re accustomed to quickly available hot water while showering, dishwashing, or rinsing gear. 

For those who are new to RVing, learning how to turn on an RV water heater isn’t complex. But there are a few nuances worth knowing, especially considering the slight differences between RVs with standard versus tankless water heaters. Let’s start with the basics of how to turn on your RV’s water heater. 

How To Start an RV Water Heater

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Photo by Camping World

Most modern RVs are equipped with a water heater that’s super easy to start by turning a switch inside the coach to the On position. Some models have multiple control switches in different locations, such as the kitchen and bathroom(s), or even an exterior switch for the electric operation. 

Your owner’s manual will always be your best resource for which type of water heater you have and where its switches are located. You can also reach out to your RV’s manufacturer or find the model number on the unit. For example, if your model number is GC6AA 10E, you know you have a combo (gas/electric) unit signified by the ‘C,’ with a 6-gallon capacity, signified by the ‘6.’

Note: Depending on the type of water heater in your RV, there might be a few additional safety and operational requirements to consider. 

How To Turn on the Propane Water Heater in Your RV

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Photo by Camping World

RV water heaters either use an electric heating element or liquid propane (LP) gas to warm water. Conventional direct spark ignition (DSI) water heaters typically have tanks with six or ten-gallon capacities, while tankless RV water heaters provide hot water by passing it through a heated coil. 

If your RV has a propane-only direct spark ignition (DSI) water heater, you’ll only need to locate one type of switch inside your coach. Although you may have multiple switches in the kitchen and/or bathroom, each should  be marked ‘LP Gas’ or simply ‘Water Heater.’

To start the ignition sequence, turn one switch to the On position. This signals the unit to send 12-volt DC power to the spark and to open the valve to supply propane for the main burner. This begins the process of heating the water. 

When left on, a thermostat controls the operation cycle. When the set water temperature is reached inside the tank, the appropriate switches open to remove DC power and close the propane valve. When that temperature falls below a set level, the cycle supplies power and opens the propane valve to re-light the burner flame.

Technician Tip: If your RV has a gas/electric DSI water heater, using the propane method allows you to heat water when you’re on the road or boondocking without a reliable source of 120-volt AC power.

How To Switch an RV Water Heater From Propane to Electric

Most conventional water heaters that use propane and/or an electric element to heat water can alternate between these two power sources. To make the switch, simply turn the control switch marked ‘LP Gas’ or ‘Propane’ to the Off position. Then, turn the switch marked ‘Electric’ to the On position.

Technician Tip: Using propane and the electric element is often labeled as ‘Quick Recovery’ because it will heat the water in the tank quicker than using only a single source. Gas only is quicker than electric only. 

How To Turn on the Electric Water Heater in Your RV

Electric-only water heaters are rare in modern RVs. More commonly, you’ll have a direct spark ignition (DSI) water heater with propane and electric heating options. The electric heating element requires 120-volt AC power, meaning it requires that your RV is connected to shore power, running the onboard generator, or plugged into a portable generator. 

With the proper electrical supply, you can turn on your RV’s electric heating element by turning the switch inside the coach marked ‘Electric Water Heater’ to the On position. This electric heating method can be used independently or simultaneously with the propane heating method for quicker recovery. 

Technician Tip: Using the electric heating element can help you save propane for use with other appliances like your furnace or cooktop.

How To Turn on the Tankless Water Heater in Your RV

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Photo by Camping World

Although often labeled as “on-demand” water heaters, tankless models still need to be turned on to operate as desired. Most RVs with tankless water heaters have a control switch inside the bathroom or kitchen. There’s typically a single switch for the entire unit. 

Once your RV is parked at a campsite or boondocking spot, you can turn that switch on because the burner to heat water only turns on when a hot water faucet is opened. When that happens (in the kitchen, bathroom sink, or shower), water flows through a coil that is heated by a flame supplied by liquid propane (LP) gas.

When the faucets are closed, a valve removes power from the control board and the burner(s). Tankless water heaters are more efficient and have a much quicker recovery time than conventional water heaters. 

While they often boast that they can deliver a “limitless supply of hot water,” your supply will still be limited by the capacity of your freshwater tank (when boondocking) or the capacity of your gray water holding tank (when connected to city water).

How To Turn on a Water Heater with Manual Pilot Ignition

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Photo by Camping World

Water heaters with manual pilot ignition aren’t as common as they once were, but they’re still widely used in the off-grid market. Their proper operation begins with ensuring propane supply to the appliance by opening the valve(s) atop your propane container(s). 

From there, open the water heater’s access panel and locate the pilot knob. Turn the knob to the ignition position and allow propane to flow to the pilot’s location. Some models require holding the knob down to turn. 

For safety, use an extended stick lighter to light the pilot. This can remain on while your RV is stationary but must be turned off before moving. To do so, turn the knob to the Off position and close the valve(s) atop your propane container(s). 

If this process doesn’t work, the most common issues are insufficient propane supply and lack of 12-volt DC power to the water heater’s control board. Contact your local Camping World Service Center for help diagnosing and repairing your RV water heater. 

How To Operate the Truma Combi Water Heater

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Photo by Taxa Outdoors via YouTube

Many modern van camper manufacturers build their models with the Truma Combi water heater and furnace. The operation is still very simple but differs slightly from the others. Here are the basic steps for operating this type of water heater: 

  1. Reset the system using the control panel to navigate to ‘Settings’ > ‘Reset.’ This gives you a clean slate. 
  2. Navigate back to the home menu and select the Thermometer icon, which accesses the settings for your hot water heater. The first menu item will be the On/Off function for the water heater. Your setting options include ECO (for warm water), Hot (for hot water), and Boost (for quick heating). Select your preference by pressing the knob – Boost is recommended if you’re ready for a shower. 

This system is nice because it lets you set your preferred cabin temperature and furnace fan speed from the same interface. 


For those new to RVing, know it’s important to drain your tank at the end of the season. This is part of the process of winterizing your RV. View this video to learn how to drain your water heater tank. 

If you’re just learning how to use your basic RV systems, these other tutorials might be helpful: 

 Do you have any questions about operating your RV’s water heater? Let us know in the comments below.

  • Comment (2)
  • Kurt Cooper says:

    To get the water heater to operate, should the water heater bypass switch be in the on or off position?

    • Hi Kurt,

      The exact position may vary based on the plumbing system design in your specific unit. At the basic level, the switch must be positioned to allow water to enter the water heater tank from either the fresh water tank or city water inlet. I’ve seen designs with 1, 2, or 3 valves, so I’d recommend consulting the manufacturer’s owner’s manual to find a diagram of the bypass design, if possible.

      What is the year, make, and model of your unit?

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