How Do RV Water Heaters Work?

Your RV’s water heater provides sizzling water to sinks and showers inside (and probably exterior) your RV. If you desire a sizzling bathe after a day of outside adventures, you’ll want your water heater to operate effectively and successfully. 

This article will assist you perceive, keep, and troubleshoot RV water heaters. 

Types of RV Hot Water Heaters

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Most trendy RVs are both outfitted with a gasoline/electrical DSI water heater, a tankless water heater, or a pilot mannequin. Pilot fashions require a standing pilot flame that have to be extinguished earlier than transferring your RV. 

DSI water heaters provide a spark igniter that initiates while you activate the management change for the gasoline mode inside your RV. Most DSI electrical and gasoline water heaters provide a six or ten-gallon water storage tank capability.

DSI stands for ‘direct spark ignition.’

Suburban and Dometic (previously Atwood) are two of the most typical manufacturers for DSI gasoline/electrical RV water heaters. Here’s an outline of every: 

Dometic 6-Gallon Water Heater Overview

Suburban SW6D Water Heater Overview

Tankless water heaters have gotten more and more widespread on new RVs. Some of the main manufacturers embody Girard, RecPro by Fogatti, Camplux, Lippert, Suburban, Truma Aqua-Go, and PrecisionTemp. 

Also generally known as “instantaneous” or “on-demand” water heaters, they warmth water because it passes by way of a coil with warmth utilized over it. Although usually used, the time period “instantaneous” could be deceptive, as they nonetheless have a 20-30 second delay to get the water heated and thru the pipes to the tap. 

One extra mannequin is an extended-range water heater or EXT. In these fashions, the temperature management is ready at 40℉ increased than in customary fashions. A mixing valve on the again blends chilly water with the superheated water from the tank to ship about 20% extra sizzling water than the tank is rated for. 

For instance, an EXT water heater with a 10-gallon tank can present as much as 12 gallons of sizzling water. These fashions function like others however require particular consideration when winterizing your RV.

Where to Find Your RV Water Heater

The location of your RV’s water heater is determined by the producer. Most place them on the off-camp aspect of your RV, reverse the primary entry door. However, your water heater’s location could be in direction of the entrance or again of your RV in case you have a rear kitchen or entrance kitchen floorplan. 

Here’s an instance of what your water heater’s exterior entry panel might appear like: 

And right here’s an instance of a water heater tank and plumbing traces from the within of an RV:

How Do RV Water Heaters Work?

Because DSI and tankless fashions are actually widespread on many RVs, let’s cowl the fundamental operations of every:

How Do DSI Water Heaters Work?

When you join your RV to metropolis water or activate the water pump after filling your recent water tank, your water heater’s tank will probably be stuffed (as long as it’s not bypassed). Ensuring the tank is full is step one in working any water heater earlier than turning the water heater on along with your RV’s management panel. 

If you’ve gotten a gasoline/electrical mannequin, you may select to make use of propane or the electrical factor to warmth water within the tank. You can even make use of each for fast sizzling water restoration. Both modes require 12-volt DC (VDC) energy. 

Propane is the first heating supply for DSI fashions. The propane is burned on the finish of the burner tube, and the flame enters the flue tube. Heat and exhaust gasses are carried by way of to an exhaust vent on the high of the water heater. 

Here’s the sequence of operation when your water heater makes use of propane: 

1. The propane management change is turned on.
2. 12 VDC goes by way of the thermostat – usually a closed change.
3. The thermostat calls for warmth and contacts shut, opening the propane valve. 
4. The spark ignites the gasoline within the burner tube. 
5. When a set temperature is attained (normally 140℉), the thermostat’s electrical contacts open, closing the gasoline valve. 

In the electrical mode, ample 120-volt AC (VAC) energy is required to warmth the electrical factor. This mode will solely be an choice when plugging into shore energy or utilizing an RV generator.

Technician Tip: The necessities for voltages, amperages, or wattages could be discovered on the information plate or in your proprietor’s guide.

Here’s the sequence of operation when your water heater makes use of electrical energy:

1. The electrical change is turned on. 
2. 120 VAC goes by way of the thermostat – usually a closed change.
3. The thermostat calls for warmth and contacts shut. 
4. 120 VAC goes by way of the ECO (power cut-off) change, usually closed.
5. 120 VAC goes to the heating factor and heats water within the tank. 
6. When the set temperature is attained, the thermostat’s electrical contacts open, eradicating energy from the electrical heating factor. 

Technician Tip: Steps 2 and 4 could also be reversed on sure fashions.

How Do Tankless Water Heaters Work?

Also generally known as on-demand, tankless RV water heaters present instantaneous sizzling water. When you open a sizzling water fixture, chilly water runs by way of a warmth exchanger that’s heated by LP gasoline. 

The burners are solely lit when a sizzling water faucet is opened. When this occurs, a valve is activated by the water stream, closing a circuit that opens the propane valve. The burners ignite and warmth the water whereas it’s flowing. When the tap is turned off, the change closed by the opening of the valve will open, shutting off energy to the water heater burner. 

Most tankless water heaters use a copper coil as a result of it offers the utmost warmth switch properties for effectivity. Multiple burners* apply warmth alongside the coil to cut back restoration time to just about zero, as there’s no water storage tank to be heated.

*Some tankless fashions boast a single, giant burner with a powered combustion air blower.

On-demand water heaters do not need a thermostat as a result of there’s no water storage tank. They are designed with redundant ECO switches that monitor the warmth as water strikes by way of the warmth exchanger. These ECO switches shut off the burner if the water temperature will get too excessive and again on when the temperature drops again into the set vary.

Learn extra about what to search for in a tankless water heater.

How to Operate an RV Water Heater

As with all RV home equipment, your proprietor’s guide is one of the best place to start out when searching for working directions. This is as a result of producers differ based mostly on the design of their water heater fashions. 

That stated, most gasoline/electrical DSI water heaters have comparable working procedures. You’ll have the choice to warmth the tank utilizing LP gasoline, 120-volt AC, or each in some circumstances. Using each permits for fast restoration. 

Quick restoration = quicker heating of water within the tank.

To use a DSI water heater, go to your RV’s management panel and activate the change to the gasoline or electrical mode – or each. For gasoline mode, you need to hear the pilot ignite inside 6-8 seconds. 

To use a tankless water heater, open a sizzling faucet and look forward to the water to run sizzling. The draw back of some on-demand fashions is that you simply’ll waste extra water as you look forward to it to warmth up, however newer fashions warmth extra effectively and scale back water consumption.

Many RV fixtures are low stream to preserve water. Typically, a stream charge of 0.8 gallons per minute (GPM) is required to shut the change that activates the tankless water heater’s burner. 

Technician Tip: If a unit has hassle activating the water heater from a number of taps, the stream restriction disc within the aerator might have to be eliminated. This will improve the stream, thereby enhancing sizzling water reliability. If the system has all the time carried out effectively and a number of taps immediately not activate the water heater, the aerator might have to be disassembled and cleaned.

How to Drain an RV Water Heater

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Your RV’s water heater needs to be drained and serviced each six months to forestall clogging your plumbing traces, taps, and showerheads. It’s the proper time to examine and exchange your anode rod, if needed, when you’re at it. 

It’s additionally necessary to empty aluminum water heaters in the event that they aren’t used for a interval of two weeks or longer. This prevents electrolysis and the build-up of micro organism and probably dangerous gasses throughout the water heater.

Because there’s a lot selection in water heater fashions put in in RVs, your proprietor’s guide is your finest useful resource for particular service and upkeep procedures. This course of covers customary DSI water heaters, not tankless water heaters.

Be conscious of the place you’re draining water. Most water heaters maintain six or 10 gallons of water, so accumulating water in two 5-gallon buckets will mean you can transport and empty into an RV dump station in the event you can’t drain water instantly onto the bottom the place your RV is parked. 

This is a matter of courtesy and respect for the location. Water from the water heater is potable and innocent, however you might depart appreciable mineral sand behind when flushing sediments out of your tank. That sand can be innocent however creates a multitude that’s tough to scrub.

Here’s the step-by-step course of for draining your RV’s water heater: 

1. Turn off the ability to the water heater and open the recent water taps inside your RV to allow them to run till the water turns chilly, permitting 2-3 minutes for the tank to chill if it has just lately been heated. The water in your tank is heated to 140℉, which may trigger burns if poured instantly from the drain. Running water within the sink till it’s cool to the contact is the most secure methodology earlier than continuing.
2. Turn off the ability to the water pump and disconnect it from metropolis water.
3. Open the stress reduction valve till the water is not draining. 
4. Remove the anode rod or drain plug and let the water drain till none stays within the water heater tank. 
5. Close the stress reduction valve and exchange your anode rod or plug as soon as drained. Use Teflon tape to wrap the threads earlier than changing your drain plug or anode rod.

If you’re seeing loads of calcium buildup out of your water heater, it could be a good suggestion to fill and drain it a second time.

Technician Tip: Camping World additionally sells a water heater tank rinser with a valve that attaches to a backyard hose. That tube inserts into the drain bung and means that you can precisely direct the steam of water across the within your water heater tank to dislodge sediment and flush it out the drain. 

How to Change your Anode Rod

Smelly and discolored sizzling water is a tell-tale signal of a nasty anode rod. Most water heater anode rods last as long as 5 years. When corroded, your anode rod not protects the liner of your sizzling water heater tank.

An anode rod is a metallic rod that extends into your tank’s inside to forestall corrosion of the tank.

Usually made from magnesium or aluminum, an anode rod attracts iron, limestone, and different minerals to forestall them from corroding the within of the tank.

Most producers advocate inspecting your anode rod yearly and changing it when it’s lower than 75% of its authentic measurement.

Technician Tip: Water heaters with a metal tank require an anode rod that primarily sacrifices itself by attracting corrosive particles and conserving them from corroding the tank’s lining. Aluminum water heater tanks don’t require an anode rod. Instead, they’ve an anodic coating utilized to the within of the tank when manufactured. 

Here’s the best way to exchange your anode rod: 

1. Obtain the right OEM (authentic tools producer) alternative as your water heater’s guide recommends.
2. Follow steps 1-5 above.
3. Inspect your present anode rod. 
4. If corroded, set up a brand new anode rod and get rid of the outdated one. Use a couple of wraps of Teflon tape on the threads of the anode rod to forestall leaks. The tape ought to say “for potable water” on the packaging. 
5. If not corroded, add Teflon tape, reinstall, and examine it once more the subsequent time you drain your water heater.
6. Ensure your stress reduction valve is closed earlier than powering up your water heater once more.

Shop water heater elements and equipment for a brand new anode rod or different alternative elements.

Technician Tip: Always use OEM alternative elements as specified by the producer. 

Why is My Hot Water Heater Not Working?

Here are a number of the most typical issues you’ll expertise along with your RV’s water heater: 

• Insufficient energy. Did you flip your water heater on? Have you checked your battery’s voltage? Have you checked your circuit breaker?
• Insufficient propane. Are your propane containers empty? Are the valves on high open to produce propane to your home equipment?
• Time delay. Have you purged chilly water from the traces? Did you wait lengthy sufficient for the water within the tank to be heated?
• Overuse. Did you utilize up all the recent water in your tank? Do it’s good to look forward to it to refill and reheat?
• No flame. Did you hear the spark ignite? Can you see a flame within the burner tube while you open the outside entry panel?
• No water within the tank. Is your T&P valve sizzling? Have you bypassed your tank and forgotten to change that valve again for regular operation?
• Hot from chilly. Are your cold and hot water traces reversed? Do you get sizzling water while you open what needs to be the deal with for the chilly water provide in your fixture?
• Bad mixing valve. Is the issue distinctive to at least one sink or fixture? Do you get sizzling water from one other fixture, resembling within the lavatory or bathe?

If you’re caught along with your water heater restore wants or uncomfortable troubleshooting, schedule a service appointment to have it inspected by an authorized RV technician. 

What questions do you’ve gotten about utilizing and sustaining your RV water heater? Let us know within the feedback under.

Tucker Ballister is our Technical Content Writer. He’s a lover of the open street and the proud proprietor of a 2021 Sunlite Classic journey trailer (his third RV so far). Check out extra of his RV adventures, gear opinions, and outside recommendation at thebackpackguide.com.