RV Water Heater Not Working? 7 Things to Check Before Replacing Parts

An RV water heater not working doesn't always mean you need a new water heater. In many cases, the problem is a heating element, igniter, thermostat, control board, gas valve, or even something as simple as a tripped breaker or incorrectly positioned bypass valve.

The fastest way to troubleshoot an RV water heater is to first determine exactly what it is doing.

• Works on propane but not electric?

• Works on electric but not propane?

• Tries to ignite but won't stay lit?

• Does absolutely nothing?

• Produces only lukewarm water?

• Leaking?

• Tankless heater won't produce hot water?

The symptom can quickly narrow down where to look.

If you already know your water heater model, you can also use the RV Water Heater Part Finder to search by manufacturer and model.

1. RV Water Heater Works on Propane But Not Electric

If your gas/electric RV water heater heats normally on propane but doesn't work on 120V electric, the problem is likely somewhere in the AC heating system.

Common causes include:

• Tripped 120V circuit breaker

• Water heater electric switch turned off

• Failed AC heating element

• Failed AC thermostat or high-limit switch

• Bad relay

• Loose or burned wiring

• No 120V power reaching the water heater

One of the most common failures is the electric heating element.

Heating elements can fail from age, mineral buildup, electrical problems, or being accidentally energized while the water heater tank is empty.

If you suspect the element, see our complete guide:

How to Replace an RV Water Heater AC Heating Element

You can also browse all RV Water Heater Parts by brand and model.

Important

Never turn an electric RV water heater on unless the tank is completely full of water. Operating an element without water can destroy it very quickly.

2. RV Water Heater Works on Electric But Not Propane

If the water heater works on electric but will not heat on propane, concentrate on the LP ignition system.

Possible causes include:

• Propane supply turned off

• Empty LP tank

• Air in the propane line

• Dirty burner

• Blocked burner tube

• Damaged igniter electrode

• Failed gas valve

• Bad thermostat or ECO

• Failed ignition control board

• Poor electrical ground

• Loose wiring

First, make sure other propane appliances operate normally.

Then turn the water heater on and listen.

Do You Hear Clicking?

Clicking normally means the ignition system is attempting to create a spark.

If you hear repeated clicking but the burner never lights, inspect the igniter, burner, gas supply, and gas valve.

On many Suburban SW-Series DSI water heaters, the Suburban 525005 Igniter Electrode creates the ignition spark and also plays a role in flame sensing.

A damaged, dirty, cracked, or improperly positioned electrode can cause:

• No ignition

• Repeated clicking

• Delayed ignition

• Burner lights and shuts back off

• Intermittent operation

Don't automatically replace the igniter, though. Verify propane supply and inspect the burner first.

3. RV Water Heater Lights But Then Shuts Off

This is another very common RV water heater problem.

The burner may ignite normally and then shut off several seconds later.

That usually means the system either:

• Cannot properly sense the flame

• Loses gas flow

• Loses the ignition signal

• Trips a safety circuit

Possible components include:

• Igniter/flame-sensing electrode

• Electrode wire

• Control board

• Gas valve

• Burner assembly

• Thermostat/ECO

• Ground connection

Start by inspecting the electrode.

Look for:

• Cracked ceramic

• Corrosion

• Incorrect gap or alignment

• Loose connections

• Damaged electrode wire

Also inspect the burner flame.

A strong RV water heater burner should generally produce a steady blue flame rather than a lazy yellow flame.

If ignition components check out but the gas valve is not opening correctly, use the complete water heater model and serial number before ordering a replacement. Gas valve compatibility can vary even between water heaters that look almost identical.

Browse Suburban RV Water Heater Parts by Model to identify the correct component.

4. RV Water Heater Does Absolutely Nothing

If you turn the water heater on and get no clicking, no ignition attempt, and no heat, start with the electrical supply before replacing parts.

For propane-fired DSI water heaters, check:

• RV 12V battery voltage

• Water heater fuse

• On/off switch

• Wiring connections

• Ground connections

• Thermostat

• ECO/high-limit switch

• Thermal cutoff

• Control board

Most modern propane RV water heaters still require 12V DC electricity to operate the control board, gas valve, and ignition system.

That means having propane in the tank is not enough.

If the control board never receives the proper power or safety signals, the ignition sequence may never begin.

Control boards are commonly replaced components, but they should generally be diagnosed after checking power, grounds, thermostats, wiring, and ignition components.

You can browse available RV water heater control boards and replacement parts.

5. RV Water Heater Is Only Lukewarm

An RV water heater producing lukewarm water instead of hot water does not always have a heating problem.

One of the first things to check is your RV's water heater bypass system.

If a bypass valve is partially open or incorrectly positioned, cold water can mix with the hot-water supply.

Also check:

• Outside shower valves

• Inside shower valves

• Mixing valves

• Water heater bypass valves

• Check valves

• Thermostat operation

Check the Outside Shower

This one catches a surprising number of RV owners.

If both the hot and cold knobs on an exterior shower are turned on but the flow has been stopped using the button on the shower head, hot and cold water may mix inside the plumbing system.

The result can be lukewarm water throughout the RV.

Turn both exterior shower valves completely off and test the hot water again.

XT Water Heaters

Some Dometic/Atwood XT water heaters intentionally heat tank water to a higher temperature and then use a mixing valve to blend it with cold water.

A problem with the mixing system can therefore affect the temperature coming from your faucets even when the water inside the tank is hot.

6. RV Water Heater Is Leaking

The first step with an RV water heater leak is identifying where the water is coming from.

Common leak locations include:

• Pressure and temperature relief valve

• Drain plug

• Anode rod

• Heating element gasket

• Water fittings

• Check valve

• Tank itself

Water Leaking From the Pressure Relief Valve

Some occasional dripping from a pressure and temperature relief valve can occur as water heats and expands.

Constant leaking should be investigated.

Possible causes include:

• Failed relief valve

• Mineral buildup

• Excessive water pressure

• Loss of the air pocket inside the tank

• Abnormally high water temperature

Never plug, cap, or disable a pressure relief valve.

On many Suburban tank water heaters, the Suburban 525045 Pressure & Temperature Relief Valve is used as the tank's safety relief valve.

Water Leaking Around a Suburban Anode Rod

Suburban tank-style RV water heaters use a porcelain-lined steel tank protected by a sacrificial anode rod.

If water is leaking around the drain/anode opening, inspect:

• Anode rod threads

• Drain opening

• Thread sealant

• Tank threads

Anode rods should also be inspected periodically and replaced once a significant portion of the sacrificial material has deteriorated.

Browse Suburban RV Water Heater Parts for replacement anode rods and related components.

Dometic and Atwood Are Different

Traditional Dometic/Atwood aluminum-tank water heaters normally use a nylon drain plug rather than a sacrificial anode rod.

Do not assume a part used on a Suburban water heater should also be installed on an Atwood or Dometic model.

7. Tankless RV Water Heater Not Getting Hot

Tankless RV water heaters operate differently from traditional 6- or 10-gallon tank water heaters.

If a Girard, Suburban, or other tankless RV water heater isn't producing hot water, possible causes include:

• Insufficient water flow

• Failed flow sensor

• Igniter problem

• Flame sensor problem

• Gas valve failure

• Blower problem

• Control board failure

• Temperature sensor problem

• Low propane pressure

• Restricted water supply

Water Flow Matters

A tankless water heater normally needs to detect adequate water flow before starting the ignition sequence.

If the flow sensor does not detect water movement, the burner may never ignite.

Restricted faucets, clogged screens, low campground water pressure, or a failing flow sensor can therefore create what appears to be an ignition problem.

Girard GSWH-2 owners can find components such as:

• Water flow sensors

• Control boards

• Gas valves

• Igniters

• Burners

• Control panels

• Heat exchangers

in our RV Water Heater Parts section.

How to Narrow Down an RV Water Heater Problem

Before ordering anything, answer these questions:

Does it work on propane?

Yes, but not electric:
Start with the 120V system, heating element, AC thermostat, breaker, switch, and relay.

No:
Continue troubleshooting the propane ignition system.

Does it work on electric?

Yes, but not propane:
Check propane supply, burner, igniter, gas valve, thermostat/ECO, and control board.

No propane or electric operation:
Look for components or electrical problems shared by both systems.

Does the burner spark?

No spark:
Check 12V power, thermostat/ECO, thermal cutoff, wiring, control board, and igniter circuit.

Spark but no flame:
Check propane supply, gas valve, burner, igniter position, and burner obstruction.

Flame starts but shuts off:
Check flame sensing, igniter condition, grounding, gas supply, and control board.

This process can eliminate a lot of unnecessary parts swapping.

Find Your RV Water Heater Model Before Ordering Parts

This may be the most important step.

Do not identify an RV water heater only by:

• Tank size

• Exterior door

• RV year

• Appearance

• "It's a Suburban"

• "It's an Atwood"

Locate the manufacturer's identification label and record:

• Manufacturer

• Complete model number

• Serial number

• Product number, if applicable

The label is usually located behind the exterior water heater access door or on the water heater housing.

Small differences in model numbers matter.

For example, a Suburban SW6D, SW6DE, and SW6DEL may all be 6-gallon SW-Series water heaters, but their electrical systems and compatible replacement parts are not necessarily identical.

Use our RV Water Heater Part Finder to search by manufacturer and model.

Common RV Water Heater Parts That Fail

Depending on the model and symptoms, commonly replaced parts include:

• Heating elements

• Thermostats

• ECO/high-limit switches

• Control boards

• Igniter electrodes

• Gas valves

• Burner assemblies

• Thermal cutoffs

• Relays

• Anode rods

• Drain plugs

• Pressure relief valves

• Flow sensors

• Temperature sensors

• Mixing valves

The goal isn't to guess which part is bad.

It's to use the symptoms to narrow the system down until you can test or identify the failed component.

Frequently Asked Questions

Why is my RV water heater not getting hot?

Common causes include loss of propane, no 12V or 120V power, a failed heating element, thermostat or ECO failure, ignition problems, a bad gas valve, a failed control board, or an incorrectly positioned bypass valve.

Start by determining whether the water heater works on propane, electric, neither, or both.

Why does my RV water heater work on propane but not electric?

The problem is likely in the 120V heating circuit. Check the breaker, electric switch, heating element, AC thermostat, relay, wiring, and incoming 120V power.

Why does my RV water heater work on electric but not propane?

Check the propane supply, igniter, burner, gas valve, thermostat/ECO, control board, and 12V electrical system.

Why does my RV water heater click but not light?

Clicking indicates that the ignition system is attempting to spark. A no-light condition may be caused by lack of propane, a dirty burner, incorrect electrode position, damaged igniter, failed gas valve, or ignition control problem.

Why does my RV water heater ignite and then shut off?

The system may not be properly sensing the flame. Inspect the igniter/flame-sensing electrode, ground connections, burner flame, wiring, gas supply, and control board.

Why is my RV hot water only lukewarm?

Check the water heater bypass valves, outside shower valves, mixing valve, and plumbing system before assuming the water heater itself has failed.

Should I repair or replace my RV water heater?

Individual components such as heating elements, thermostats, igniters, control boards, gas valves, burners, and sensors can often be replaced.

Complete water heater replacement may make more sense if the tank itself is leaking, the heat exchanger is badly damaged, freeze damage has occurred, multiple expensive parts have failed, or replacement parts are no longer available.

Find the Right RV Water Heater Part

At RVWaterHeaterParts.com, we specialize specifically in RV water heaters and replacement parts for:

• Suburban

• Dometic

• Atwood

• Girard

Shop by manufacturer, water heater model, or part category to find the correct heating element, control board, thermostat, igniter, gas valve, burner, sensor, anode rod, or other replacement component.

Before ordering, identify your complete water heater model.

A little troubleshooting first can save you from replacing three good parts trying to find one bad one.