How Does an RV Water Heater Function?

Lighting Propane Water Heaters

Many RV water heaters are heated by propane gas. The propane gas flows through a valve into a burner, where it is lighted. In some burners, a small pilot light keeps burning all the time. When the burner is turned on, the pilot light ignites the gas. In direct spark ignition systems, the gas is ignited by an electric spark. This saves energy, because the pilot light does not have to keep burning.

Heating The Water

Once the gas is ignited, the hot gasses run through a heat exchanger. The heat exchanger is a tube that runs through the water. The heat flows through the pipe into the water, heating it. Then, the combusted gasses flow out of the tube into the air outside the RV.

Electric Water Heaters

Electric water heaters use a sealed electric element to heat the water. The element is made out of a resistor, a type of material that resists the flow of electricity. When electricity flows through the heating element, the element turns it into heat. Because the element is sealed, it can go directly through the water tank, where it transfers heat into the water.

The Hot Water System

RVs have a large water-storage tank that powers the shower, toilet and sink. A pump pumps water out of that tank into a hot line and a cold line. The hot line goes into the water heater and then flows to the sink and shower. The cold line flows directly to the sink, shower and toilet. When someone turns on the hot water in the shower or sink, it flows from the hot water tank to the appliance, where it is mixed with cold water to get the right temperature.