RV Water Heater Guide to Types, Parts, Electric Conversions & More

Camping with an RV water heater hardly seems like roughing it. Taking hot showers in one's own bathroom is a luxury tent campers can only dream of. Hot water anytime and anywhere makes RV life oh so comfortable. If you'd like to keep that hot water pumping through your pipes, then join me for a look at the hot water heaters that make it happen...

Article Topics:

  • RV Water Heater Types
  • Atwood Water Heaters
  • Suburban Water Heaters
  • RV Tankless Water Heaters
  • Common Water Heater Components
  • Electric Conversions For RV Propane Water Heaters
  • Boondocking Hot Water Tips

RV Water Heater Types

Electronic Ignition / Direct Spark Ignition (DSI)

Direct Spark Ignition (DSI) RV water heaters such as the Atwood 6 Gallon LP with DSI model are the most common today. This water heater is fully automatic. Once the heater's tank is filled, simply flip a switch to turn it on. It is controlled by a printed circuit board.

RV Water HeaterRV water heater with pilot ignition

Pilot Ignition

Pilot Ignition RV Water Heaters like the Suburban 6 Gallon LP/Pilot model are the second most popular type and have been around for several years thanks to their reliability and simplicity. Pilot models are less expensive than DSI models.

The pilot light must be lit manually - which is easy to do once you reach your destination. Some models feature a pilot re-light ignition which automatically re-lights the pilot, if it goes out due to wind.

RV Tankless Water Heater or Instantaneous

RV Tankless Water Heaters, as the name implies, have no water storage tank. The Atwood On-Demand Water Heater is an example, and is made to be a direct replacement for a standard 6 or 10 gallon water heater. Water flows through a coil which is heated by an LP flame. The burner is only lit when a hot water faucet is turned on. Once the faucet is turned off, the burner goes out.

A few early models used a pilot light, however most today are fully automatic, like the DSI units. There is no waiting for hot water and no running out as an RV tankless water heater can supply an unlimited amount of hot water.

These water heaters are pretty much maintenance free, as long as the LP regulator is functioning properly.

RV Electric Water Heater

An RV Electric Water Heater was featured on some early RVs. It is powered by 120 volts alternating current (AC). The water heater is only functional when plugged into shore power, or when a generator is used.

Propane/Electric Combo

Some RVs today have a Propane/Electric Combo RV Water Heater like the Atwood 6 Gallon LP/Electric/DSI model. This type has an electric heating element inside the water storage tank. It can operate on propane when RV boondocking and 120 volts AC when plugged in at the campground.

With most, both propane and electricity can be used simultaneously, providing even faster water heating. Propane typically heats water faster than the electric heating element.

Atwood Water Heaters

Atwood Water HeaterAtwood water heater

Atwood has been making water heaters for RV and marine use for over 30 years. They are the largest manufacturer of RV and marine water heaters. Some features of Atwood water heaters are:

  • Lightweight - Lighter than Suburban models.
  • No Anode Rod - Atwood Water Heaters have an aluminum clad tank which eliminates the need for an anode rod.
  • Features a "through-tube" combustion chamber that allows the pilot flame to provide water heating. When camping in warm weather, I find the pilot flame is all that is needed to keep the water sufficiently hot.
  • Access door is included

Suburban Water Heaters

Suburban Water HeaterSuburban water heater

Suburban has been a supplier to the RV industry for over 40 years. Suburban water heaters feature:

  • Porcelain-lined steel tank with anode rod that absorbs the corrosive action of heated water. The anode rod is sacrificed (instead of the tank) and this prolongs the life of the storage tank. The anode rod needs to be replaced periodically.
  • More RV water heater sizes available than Atwood. In addition to 6 and 10 gallon models Suburban also has 4, 12, and 16 gallon sizes.
  • Access door sold separately

RV Tankless Water Heaters

Girard RV Tankless Water HeaterGirard tankless water heater

No tank means no wait, for hot water, and less weight. RV tankless water heaters also use less propane than tank types. Yes, there are many advantages to going tankless - except for one: price. They tend to be a bit more expensive, but prices are coming down.

How RV Tankless Water Heaters Work:

  1. You turn a hot water faucet on.
  2. Cold water enters the heater.
  3. A water flow sensor detects that water is flowing.
  4. The microprocessor based circuit board automatically ignites the burner.
  5. Water enters the heating coil.
  6. The water is heated to the set temperature.
  7. Once the hot water tap is turned off, the unit shuts down.

Precision Temp RV-500

The Precision Temp RV-500 has been around for a few years now. It uses almost 50% less propane than tank models. It makes a good replacement for a 10 gallon RV water heater and will even fit the space of a 6 gallon model with a small adjustment to the cutout height.

Features of the Precision Temp RV-500:

  • Up to 55,000 BTUs of power
  • A 20 lb propane tank will provide approximately 940 gallons of shower temperature water
  • Provides consistent water temperature
  • Water temperature can be adjusted from 90° to 135°F

Girard Tankless RV Water Heater

The Girard Tankless RV Water Heater is relatively new on the market. It's roughly the same size as the Precision Temp RV-500 so it would also be a good replacement for 6 and 10 gallon RV water heaters.

Features of the Girard Tankless RV Water Heater:

  • Water temperature is based on the flow of water. Higher flow rates will provide cooler water, slower flow rates will provide hotter water. In other words the water temperature changes depending on how far you turn the faucet knob.
  • Uses up to 60% less propane than storage tank model water heaters.
  • Burner switches between high and low flame depending on the temperature of incoming water.

Portable Tankless Water Heaters

Water heaters like the EccoTemp Portable Tankless Water Heater can be used anywhere outdoors. All that is needed is a supply of water via a water pump or faucet, and a propane tank. They can be connected to a standard garden hose.

These heaters use batteries for ignition and the water temperature is usually adjustable. They tend to be less expensive than installed RV tankless water heaters.

Common Water Heater Components

It's useful to know what the different components of an RV water heater do, especially when it comes time for maintenance and repairs. Thankfully, water heaters are one of the easiest appliances to work on as most components are accessed from a compartment outside the RV. Only occasional maintenance is required. Here is what you'll find on the most common types of RV water heaters (DSI and Pilot Ignition models):

Water Storage Tank

Stores the hot water and is insulated to retain heat.

Pressure and Temperature Relief Valve (P&T Valve)

RV Water Heater P&T Valve

Releases water from the tank before the temperature or pressure exceeds the specified limit. The P&T valve prevents the tank from rupturing, with potentially disastrous results! During each heating cycle the P&T valve will typically drip some water, and this is normal.

Drain

RV Water Heater Drain

Located on the front of the unit near the bottom. The drain will either have a valve or a threaded pipe plug. When draining the tank turn the hot water faucets on - this will aid in draining. It's good practice to drain and flush the tank every season, or twice a year for fulltimers.

Main Burner Orifice

RV Water Heater Main Burner Orifice

Channels the LP from either the gas solenoid valve (for DSI types), or gas control valve (for Pilot models) to the mixing tube.

Mixing Tube

RV Water Heater Mixing Tube

Mixes propane with air prior to burning at the main burner. The mixing tube must be kept clean and properly aligned.

Primary Air Adjustment

RV Water Heater Air Adjustment

This should be adjusted when the main burner is burning. Adjust it so the flame is mostly blue, with some orange tinges. If the burner can be heard from more than 5 feet away with the water heater door closed, you may need to adjust the flame. It should not sound like a roaring blow torch.

Electric Conversions For RV Propane Water Heaters

RV Electric Water Heater Conversion

If you'd like to save some propane while plugged in at the campground, consider adding an electric heating element to your existing RV water heater. Electric Conversion Kits like the Hott Rod Water Heater Conversion Kit pictured here install in your drain plug opening and allow you to heat water with 110 volt AC power.

Your propane system remains intact so you can heat water with either LP, electricity, or both LP and electricity at the same time - providing even faster water heating. The Hott Rod has a thermostat with a water temperature setting of 90° to 150°F. One warning though: one of these electric conversions may void your water heater warranty. Check with your owner's manual or contact the manufacturer if you're in doubt.

RV Boondocking Hot Water Tips

Taking a hot shower in the middle of nowhere far from civilization is just as easy as taking one while staying at a posh campground with full hookups. RV boondocking certainly does not mean roughing it! Of course if you want to keep that steamy liquid pumping through your pipes, you may need to practice a little conservation.

Doing without the 20 minute showers is a good place to start. You'll want to conserve both water and propane if you plan to make the wilderness your home for any length of time. You can conserve water in the shower by installing a low flow showerhead and an on/off valve. The on/off valve will allow you to stop the flow without messing with the hot/cold mix - great for taking "navy showers" to conserve water.

RV Water Heater Pilot ModeWater heater on pilot mode to conserve LP

One way to conserve propane is to turn the RV water heater on only when needed, and to leave it off the rest of the time. It typically takes 30-45 minutes for the heater to fully heat the water, so by planning ahead you'll know when to turn it on. If you have a pilot model, you may find that leaving the heater on pilot mode will keep the water sufficiently hot. In fact, when camping in Arizona (wintering in the desert, or summering in the mountains) I find the pilot light alone keeps my water plenty hot.

Choosing an RV tankless water heater is another way to conserve propane. Tankless models use up to 60% less propane than tank models.

Conclusion

That's it for RV water heaters for now. Hope you learned a thing or two. Thankfully water heaters aren't terribly complicated and as you've seen, when you want hot water from the tap there are plenty of options.

References

Woodall's RV Owner's Handbook by Gary Bunzer

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