The water heater in an RV is one of the most essential appliances for camping or living comfort. RV Water Heaters are mostly reliable provided you maintain them properly.
What are symptoms of an RV water heater needing repairs?
- Leaking connections
- Failure to heat on propane
- Failure to heat with 120 volts AC
- No heating at all
- Excessive noise or loud popping from the propane burner
- Water is warm but does not get hot
Warning! See footnote about safety when working on or around RV water heaters.
Leaking connections are almost always evident by water appearing on the floor, in a cupboard, or leaking under the RV. This is where you need to trace the source and a lot of investigation is sometimes required. I start at the top of the heater and work down. Look for obvious water stains at the water connections. These stains can be sometimes be dry because the warmth around the heater evaporates very slow leaks.
At the back of every water heater, water pipes can simply be loose. Dry your hand and run your fingertips where the main water lines connect to the heater. If you can feel water, this is a good start in finding the problem, although the drops of water may be from somewhere else, and have just run along to the point you found water. Sometimes the remedy is as easy as hand tightening the connection. Plastic connections require hand tight, plus a quarter turn. Do not over-tighten, and if it is still leaking, remove the connection and add thread sealer or teflon tape, or both. If leaking still persists, then you will need to replace the connection.
If you look everywhere and there is no obvious source, but water is still appearing, you may need to tie small rags or paper towels around various points of the piping and connections. Usually the highest, wettest rag is nearest to the leak.
Ruptured RV water heater tanks can also cause slow leaks. A tank in the extreme cold can freeze with water inside, the expansion of the frozen water cracks and warps the tank. RV water heater tanks can also rust and corrode. This occurs in steel tanks, usually Suburban RV water heaters. While these are lined with ceramic coating, the tank can rust and corrode if the anode rod is not replace frequently. Anode rods need inspection yearly, and are easily replaced with a 1 and 1/16 inch socket. Dometic’s Attwood RV water heaters have an all aluminum tank, which does not require an anode rod. You can purchase an anode rod for Attwood heaters from aftermarket suppliers, though it is not necessary.
RV Water Heater not working on Propane?
RV Water Heaters almost always operate with propane, with many having 120 volt AC electric capability too. In a campground, you can use the 120 volt AC electric element to heat your water with the electricity provided by the campground. Boondocking or dry camping is where you will want the propane function.
If your RV water heater won’t heat using the propane function, the very first place to check is your propane supply. Either check at the tank or cylinders, and run your propane cooktop to make sure you have a strong flame. Check if you have 12 volts of DC power streaming from your house battery. 12 volts is required to operate the circuit board in RV water heaters. If your battery is flat, and the converter is not producing power, then your water heater will not operate.
If propane is in good supply, then your next check depends on whether you have a direct spark ignition (DSI), or a standing pilot light. DSI is usually identified by having a switch inside your RV. Pilot light models have a means to manually light the pilot light behind the outside panel of the RV’s water heater.
Water heaters with DSI ignition have a red light adjacent to the switch that lights if the ignition sequence fails. After the switch is moved to the ‘On’ position, you have time to go outside to the heater panel and listen for the cracking sound from the spark igniter. This spark ignition automatically makes three separate attempts before the system shuts down. At this point, the red light will glow inside the RV, signifying a failure to light the propane. To recycle the system, move the switch to ‘Off’, then back ‘On’ and the three start cycles will begin again. If you do not hear the spark ignition operating, there is a fault in the spark electrode or the controlling circuit board. Call Happy Campers RV Repairs for certified advice.
There are times when you will have just changed propane cylinders, and air could have entered the propane lines. In this instance, run all three burners, (safely!), on your propane cooktop for a few minutes, then attempt a relight. It is possible that you may have to repeat the process several times before the air is purged from the system and the water heater burner will ignite.
Failure to heat using propane can be a complex problem, if bleeding the air from the propane line is not providing results, it may be time to contact us at Happy Campers RV Repairs for a full diagnosis.
Failure to heat water with the 120 volt AC supply.
Happy Campers RV Repairs recently met several customers who did not know they could use anything other than propane to heat their water. In all three cases, there was a switch inside the RV to start the propane heating, meaning the water heater has a DSI or direct spark ignition system, but no switch to use the 120 volt AC method of heating.
In each of these systems, there was an electrical supply switch hidden behind the RV water heater’s outside hatch cover. Look carefully in the lower left side of the opening and you will see a small black rocker switch. Move this to ‘On’, and now you have 120 volts supply heating the water and you can switch off your propane at the water heater switch inside the RV. The advantage here is to use the campground’s electricity and save on propane. Many RVs have both 120 volt and propane switches side by side inside the coach.
Some reasons your RV water heater will not heat up on electricity:
- Circuit breaker tripped – located in the RVs electrical control panel. Remember to switch the circuit breaker all the way off and then back on.
- Power not connected at the campground pedestal. Check that the circuit breaker on the pedestal is all the way off then all the way on in case it has tripped. Check to see if other 120 volt AC circuits are operating. Is you microwave functioning? If not, there could be a fault in your RV’s 120 volt circuits, or the campground.
- A 12 volt relay may not be switching the 120 volt circuit properly.
- Wiring may be loose or broken.
- The electric heating element may be defective.
The various brands and models of RV water heaters are configured differently with thermostats and emergency cut-off devices. All have several of these thermostats and the systems will respond differently depending on which cut-off device or thermostat has failed. Contact Happy Campers RV Repairs for assistance and quick and accurate diagnosis.
Tankless or continuous water heaters
Tankless water heaters do not store hot water in a storage tank which saves on weight and removes the need to keep gallons of water heated throughout the day and night. This means the tankless design is compact and lightweight. The Girard tankless systems don’t require 120 volt electricity supply, and only use .3 amps 12 volts of power and propane to heat the water. They operate only when you turn on the hot water faucets, and the hot water is just as promptly delivered as with a storage tank. Another huge advantage from tankless RV water heaters is that the supply of hot water is almost limitless. This is great if you want long showers or for more than two people in an RV. They cost a little more to purchase, but installation is fairly simple. The makers of the tankless water heaters provide kits to match the obsolete water heater in your RV.
Check with us today about a replacement tankless RV water heater.
Warning! There is a risk of burn, electric shock and pressure related injuries when working with on RV water heaters. There are also sharp metal pieces which may cause open-wound injury. Water pressure inside the water heater may cause projectile related injuries to eyes. Only proceed with RV water heater maintenance when it can be verified that there is no hot water inside the water heater and the town water pressure and RV fresh water pump pressure is shut off. Water heaters may operate with 120 volt AC electricity which is dangerous. It is recommended to consult a certified electrician or RV professional before attempting any work on or around an RV water heater. Internal water temperatures may reach near boiling temperature. Ensure the water in the water heater is cool before operating on the water heater. Either allow the water to cool over at least 12 hours with no power or propane supplied to the heater, or switch off all power and propane supply and run a hot water faucet for ten minutes to drain all hot water and replenish with cool water. Shut off town water supply and switch off the fresh water pump inside the RV so that there is no risk of projectile injuries from water pressure. Wear protective gloves to avoid risk of skin injuries from sharp metal pieces. Eye protection should be worn to prevent projectile injuries from water pressure.
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