RV Water Heaters: All You Need to Know

A water heater is one of the absolute essential equipment for RVs and campers. Their function is the same as that of the water heater you find at your home or anywhere else. But these water heaters are different in their own unique way. There are differences in capacity, functionality as well as troubleshooting and maintenance.

If you’re out camping and your water heater fails, good luck finding an A star service to repair it while you try to become one with nature. Your credit card, then, becomes just a piece of plastic. Therefore, it’s crucial to know how it works and how to maintain it when you’re carrying one with you.

(RV is short for Recreational Vehicle, also called as caravan.)

What’s so special about this ‘RV Water Heater’?

Since these water heaters are stationed in an RV, they have a lesser capacity than your average household water heater. The lowest capacity one can usually heat up to 6 gallons of water. There are others with increasing capacity, up to 10-gallons. It is important to note that ‘capacity’ can very well be a marketing gimmick.

If you do find a higher capacity heater (16 or more gallons) it usually refers to the throughput of the heater. The actual holding capacity is approximately 10 gallons. The rest of its capacity is derived from the amount of water mixed at the faucet. So keep this in mind before falling for ‘bigger is better’.

There are different kinds of RV water heaters, and the right buying choice depends on your preference as well as the make and model of your RV. But you can refer to a buying guide for that. However, tank-less or propane-operated water heaters are increasingly making their presence known. They might be a little expensive than conventional ones; ironic considering they are ‘tankless’.

But the higher price is probably justified because they use less resources. Instead of burning fuel constantly to keep the water in a tank hot at all times, these water heaters only start operating when you need the hot water.

Nice! So how does it operate?

They have different modes of operation depending on the fuel source they use. The most common modes are the LP (Liquid Propane) mode and hybrid mode.

  • LP mode (Liquid Propane): – Propane is a domestic fuel and can be easily adapted to water heaters. There is usually a unit or a container which can be refuelled with LP available commercially.
    • Additionally there are different models available based on their ignition mechanism. Most older ones use a pilot light. You need to manually switch it on which ignites the flame and the water gets heated. There is a safety mechanism which automatically closes the gas valve if the pilot light is off or if it is blown out by the wind. Even then, it is usually recommended to have the heater off for safety when the vehicle is moving.
    • The more advanced ones use a system called DSI (Direct Spark Ignition). As with all the technological advancements, this system is designed to reduce the element of human error. Instead of a pilot light, a thermostat senses the temperature of the water and uses a PLC (Programmable Logic Controller) to open or close the gas valve, and ignite a flame. A similar safety measure is implemented here, wherein a sensor detects if the gas is actually burning and a flame exists. If either of them have their status otherwise, this system closes off the gas valve for maximum safety. Depending on the model, the heater needs to be reset to get it functioning properly again.
    • As with any water heater, it is up to the owner to have it on continuously or use it judiciously to have a constant hot water supply or save fuel, respectively.
  • Hybrid mode: – Although you may find some water heaters operated only by electricity, the hybrid ones seem more useful than the electric ones. The advantage of a hybrid system is that you have option to use propane or electricity; and the modes can be switched based on the availability of either resource. Contrary to the LP mode water heaters (including the DSI ones) which may use just a 12V supply for the ignition system, most of these require a 120 Volt, 12 Ampere electric supply to operate efficiently. So you have to make sure that your RV battery is up to the mark in terms of power draw. Some owners prefer separate batteries for the RV engine and the electrical equipment, but it all boils down to personal preference. The obvious advantage of the hybrid system is that it will automatically switch to LP mode in case the battery runs out or the electric mode if the fuel dries up. Or, you may need to manually switch modes. Again, this depends on the model you purchase.

RV Water Heater Maintenance

As with all things, RV water heaters require maintenance too. But it does not require your constant attention (unless you prefer tinkering with it instead of actually driving your RV and camping somewhere nice). The model that you choose also dictates how often you will need to open it up and start poking around. The usual culprits that you’ll be looking for, should you choose, are given below:

  • The water tank: – When you are around the country side in your RV, the chances of getting triple distilled and filtered water decrease substantially. According to the water that you fill in your water tank, you will begin to notice some deposits in your tank after a while. These may be sediments or algae or other pollutants you might find in the water. You need to clean up these deposits to extend the life of your water heater; and to do that you need to flush your tank of all the water. Commercial rinsing and spraying equipment is available for a few dollars to make this task easy.
  • Anode rod: – If your water tank is lined with steel or other iron compound instead of glass, this anode rod prevents it from corrosion. It usually reacts with the corrosive elements in the water before they affect the lining. These anode rods need to be replaced once in a while to ensure the safety of the tank. It can be removed using a socket wrench, but the amount of pressure needed to do that depends on the amount of damage that the rod has suffered.
  • Anti freeze loop system: – These consist of tubular water liners that need to be filled with anti-freeze compounds if you happen to be in one of the colder climates. These compounds are extremely corrosive and damage the anode rod or the tank lining prematurely resulting in heavy sedimentation, if they find their way inside the unit while installation or refilling. A bypass kit usually takes care of that, but it is a good practice to drain the tank before successive refills.
  • Burner tube: – The gas valve is connected to the burner tube and over the period of some time, debris and other impurities may start depositing. Naturally, this part needs annual or half-annual check-ups and cleaning to ensure an uninterrupted gas supply to the flame.

What to Do When Something Goes Wrong?

What’s the worst that could happen? The water heater unit will stop working. It’s easy to find out the probable cause if you look out for some common issues:

  • Fuel: – It may sound daft, but you need to check if there’s enough fuel in the system or if the battery powering it is dying out. This is one of the simplest causes, yet often overlooked in the rush of things.
  • Tubing: – Sometimes, the tubing system for the gas becomes plugged by insects during times of inactivity or deposits of soot. The gas supply dwindles, affecting the flame. When you are on your periodic clean up, you can clear the tubing of any nests, webbings or soot to get rid of this problem.

Other possible causes require you to refer to the user manual of your RV water heater for troubleshooting if you are a DIY enthusiast. Examples include: a) outage of the pilot light; b) absence of sparks on electrodes; c) improper positioning of parts; d) burnout of the heating element, etc.

In cases of the ‘rotten egg syndrome’ from the faucet, the problem is hydrogen sulphide, which gets released because of the chemical reaction from the hydrogen and sulphur present in the water or released by bacteria. To get rid of this problem, the heater unit and faucet needs to be flushed with vinegar, hydrogen peroxide and chlorinated water in their appropriate proportions. More information can be found in the user manual.

In conclusion
Modern RV water heaters can last as long as you want them to, with proper usage, maintenance and troubleshooting. It is quite a useful appliance if you think about its utility when you are on the move in your caravan.

Read more:
1. Water Heater 101
2. How to Hire a Plumber? The Top Tips
2. Water Heater Leaking: What Should You Do?

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