A Furrion tankless RV water heater that suddenly stops producing hot water doesn’t necessarily have a failed heater.
One of the first things I check with any RV on-demand water heater is water flow.
Unlike a conventional tank-style water heater, an on-demand heater has to detect enough water moving through the unit before it can operate properly. Low campground water pressure, a plugged faucet aerator, a restricted filter, air in the plumbing, or another flow problem can sometimes look like a water heater failure.
This guide covers the safe checks an RV owner can make before calling for service, along with the common error codes used on Furrion FWH09A-series tankless water heaters.
Important: Furrion has produced different generations of tankless water heaters, and error-code meanings are not identical on every model. The codes below apply to the FWH09A/FWH09AFA family. Check the model number on your water heater and verify the code with the manual for your specific unit.
Check These First
If your Furrion tankless water heater isn’t producing hot water, start here:
- Check the water flow.
- Make sure the propane supply is turned on and the tank isn’t empty.
- Check whether other propane appliances work normally.
- Make sure the water heater has 12-volt DC power.
- Look at the wall controller for an error code.
- Check the exterior exhaust for an obvious obstruction.
- Reset the heater once and see whether the fault returns.
If one of these checks identifies the problem, you may not need to go any further.
Furrion Error Code Quick Reference
If your Furrion controller is displaying an error code, use this table as a starting point. More detailed troubleshooting for each code is included farther down this guide.
| Code | Meaning | Safe First Check |
|---|---|---|
| E0 | Outlet temperature fault | Reset once; service if it returns |
| E1 | Ignition/flame failure | Check propane supply and other gas appliances |
| E2 | Abnormal flame signal | Reset once; service if it returns |
| E3 | Over-temperature safety fault | Run cold water briefly, allow cooling, restart |
| E4 | Inlet temperature fault | Reset once; service if it returns |
| E5 | Air pressure/exhaust fault | Check exterior vent and wind conditions |
| E6 | Temperature surge | Check water supply, flow, filters and hot/cold mixing |
| E7 | Gas solenoid valve fault | Service required if code returns |
Note: These codes apply to the Furrion FWH09A/FWH09AFA family. Older Furrion tankless water heaters may use some error codes differently. Always confirm the model number before using an error code for diagnosis.
Safety Stop
A Furrion tankless water heater combines propane, an ignition system, electricity, hot water, and combustion exhaust.
There are several things an RV owner can safely check, but troubleshooting should stop if it requires disassembling the burner, adjusting the gas regulator, testing the gas valve, bypassing a safety device, or performing electrical tests you’re not qualified to perform.
Stop using the water heater and arrange for service if:
- You smell propane.
- You see evidence of fire, scorching, or melted wiring.
- Water is leaking onto electrical components.
- The heater repeatedly overheats.
- A safety-related error immediately returns after resetting.
- The repair requires opening or modifying the propane system.
If you smell propane, shut off the propane supply if it is safe to do so, avoid operating electrical switches or ignition sources, ventilate the area, and have the propane system inspected.
Never bypass a temperature sensor, pressure switch, ECO, flame sensor, or other safety device to keep the heater operating.
Check First: Does the RV Have Enough Water Flow?
This is one of my first checks when diagnosing an RV on-demand water heater.
A tankless water heater doesn’t simply keep a tank of water hot. It has to recognize water flowing through the heater before the heating sequence can operate correctly.
Start by opening a hot-water faucet fully.
Is the flow strong?
If water barely comes out of the faucet, deal with the water-flow problem before assuming the Furrion heater has failed.
Check:
- Is the campground water supply fully turned on?
- Is the fresh-water tank full enough when using the RV pump?
- Is the RV water pump operating normally?
- Is the water-pressure regulator restricting flow?
- Is a plumbing valve partially closed?
- Is the faucet aerator plugged?
- Is the showerhead restricted?
- Is there air trapped in the plumbing?
- Is the water heater’s inlet filter restricted?
If the campground has poor water pressure, try filling the fresh-water tank and using the RV’s onboard water pump.
I’ve encountered situations where an on-demand water heater appeared to have a problem when the real issue was simply that there wasn’t enough water flow for the heater to operate correctly.
Try More Than One Faucet
If the kitchen faucet has poor flow but the bathroom faucet has strong flow, the problem may be at the fixture rather than at the water heater.
Faucet aerators are particularly easy to overlook. Sediment can restrict an aerator enough to significantly reduce flow.
Check the Propane Supply
If water flow is good, check the propane supply.
Make sure:
- The propane tank contains fuel.
- The propane valve is fully open.
- Other propane appliances operate normally.
If the RV has been sitting or the propane supply was recently turned off, there may also be air in the propane lines.
Trying another propane appliance can provide useful information. If the stove and furnace also won’t operate correctly, the problem probably isn’t isolated to the water heater.
Do not attempt to adjust propane pressure yourself unless you are qualified to work on RV propane systems.
Check the Wall Controller
The Furrion wall controller is one of your most useful diagnostic tools.
If the display is completely blank, you may be dealing with a power problem rather than a heating problem.
Check the RV’s:
- Battery condition
- Battery disconnect
- 12-volt fuse panel
- Water-heater fuse
- Relevant 12-volt connections that are accessible without dismantling the appliance
If the controller has power and displays an error code, write the code down before resetting the heater.
That code can save a considerable amount of diagnostic time.
Furrion FWH09A Tankless Water Heater Error Codes
E0 — Water Outlet Temperature Fault
E0 indicates a fault involving the outlet-water-temperature sensing circuit.
What you can safely check
There isn’t much external troubleshooting an RV owner can perform for this code.
Try one reset. If E0 returns, the temperature sensor, wiring, connection, or control system may require professional diagnosis.
Repeated E0: Book service.
E1 — Flame/Ignition Failure
E1 indicates that the heater was unable to establish the proper flame signal during ignition.
Before assuming there is an ignition-system failure, check the simple things.
Check:
- Is there propane in the tank?
- Is the propane valve open?
- Do other propane appliances work?
- Was the propane supply recently disconnected or turned off?
Low propane pressure can also cause ignition problems, but regulator pressure should be tested by a qualified technician rather than adjusted as a DIY repair.
Most likely direction
No propane anywhere in the RV: Start with the RV’s propane supply.
Other propane appliances work normally but E1 repeatedly returns: The Furrion heater needs further diagnosis.
Possible internal causes can involve the ignition system, flame sensing, gas supply to the appliance, wiring, or related controls.
E2 — Flame Signal Fault
On the FWH09A-series documentation, E2 indicates an abnormal or false flame signal.
This is generally not an owner-serviceable problem.
What you can safely do
Turn the heater off, wait several seconds, and restart it once.
If E2 immediately returns, arrange for service.
Model warning: Older Furrion tankless heaters may use E2 differently. Always verify the code against the manual for your exact model.
E3 — Over-Temperature Mechanical Sensor Fault
E3 relates to the heater’s mechanical over-temperature protection.
Furrion’s troubleshooting procedure calls for running cold water for approximately 10–20 seconds and then restarting the appliance.
What you can safely do
- Turn off the hot-water demand.
- Allow cold water to flow.
- Let the heater cool.
- Restart the appliance.
If E3 returns, stop resetting the heater repeatedly.
An overheating safety fault needs to be diagnosed rather than bypassed.
E4 — Water Inlet Temperature Fault
E4 indicates a problem involving the inlet-water-temperature sensing circuit.
What you can safely check
There is little external troubleshooting to perform.
Reset the heater once.
If E4 returns, the temperature sensor, wiring, connector, or controller may need professional diagnosis.
E5 — Air Pressure / Exhaust Fault
E5 points toward the combustion-air or exhaust system.
This is one code where there are a couple of useful things an RV owner can safely check.
Check the exterior vent
With the heater off and cool, inspect the exterior water-heater vent.
Look for obvious obstructions such as:
- Leaves
- Debris
- Insect nests
- Mud-dauber nests
- Snow or ice
- Objects stored against the heater exhaust
Do not insert tools deeply into the combustion system or dismantle the blower assembly.
Is it extremely windy?
Strong wind blowing directly into the exhaust can sometimes interfere with operation.
If the fault occurs only during strong winds and disappears when conditions change or the RV is repositioned, wind may be contributing to the problem.
If the vent is clear and E5 continues, the blower, air-pressure sensing system, wiring, or another internal component may require service.
E6 — Temperature Surge
E6 is one of the more useful codes for an RV owner because the cause isn’t necessarily a failed component.
It can be associated with:
- Sudden changes in cold-water flow
- Too much hot/cold mixing
- Insufficient water supply
- Insufficient water flow
- Air in the plumbing
- A restricted filter
Start with water flow
Make sure the city-water connection is fully open or that the fresh-water tank contains enough water.
If campground pressure is poor, try using the RV’s onboard water pump.
Purge air from the plumbing
Run the hot and cold faucets until the water flows steadily without sputtering.
Check for restrictions
Inspect easily accessible items such as:
- Faucet aerators
- Showerhead
- Water filters
- Water-pressure regulator
The Furrion water heater itself also has a filter that may require cleaning according to the manufacturer’s maintenance instructions.
Reduce hot/cold mixing
This is another characteristic of on-demand heaters that’s worth understanding.
Instead of setting the heater extremely hot and then adding a large amount of cold water at the shower faucet, try setting the Furrion controller closer to the temperature you actually want to use.
For example, if you find a particular temperature comfortable for showering, set the water heater near that temperature and use mostly hot water.
That maintains more flow through the hot-water side and can help an on-demand system operate more consistently.
Does the problem happen when someone uses another fixture?
If the shower temperature suddenly changes whenever someone flushes the toilet or opens another faucet, you’re probably looking at a water-flow or pressure issue rather than a random heater failure.
E7 — Solenoid Valve Fault
E7 indicates a fault involving the heater’s gas-control solenoid/valve circuit.
This isn’t something I recommend an RV owner attempt to repair.
You can reset the heater once to rule out a temporary fault.
If E7 returns, arrange for professional service.
Do not bypass, modify, or attempt to force the gas valve open.
Furrion Water Heater Has Water Flow but Won’t Ignite
If you have strong water flow but the burner doesn’t ignite, look at the wall controller.
No error code
Confirm that:
- The heater is switched on.
- The controller is calling for hot water.
- The propane supply is available.
- The RV has adequate 12-volt power.
E1 appears
Concentrate on propane availability first.
If other propane appliances operate normally and E1 continues, the problem is more likely inside the water heater and may require a technician.
Furrion Water Heater Works on the RV Pump but Not City Water
This is an important diagnostic clue.
If the heater works normally using the RV’s fresh-water tank and pump but has problems when connected directly to campground water, suspect the incoming water supply before replacing anything.
Check:
- Campground pressure
- Water-pressure regulator
- Inline water filters
- Hose restrictions
- Partially closed valves
The RV pump can provide a more consistent supply than a poor campground connection.
Furrion Water Heater Gets Hot, Then Cold
Hot-cold-hot temperature cycling is often related to changing water flow.
Before blaming the heater, check whether:
- Someone is using another faucet.
- The toilet is being flushed.
- The showerhead is a very low-flow model.
- The water-pressure regulator is restrictive.
- The campground pressure fluctuates.
- You’re mixing large amounts of cold water into the hot supply.
- A filter or aerator is partially plugged.
Try setting the heater closer to the temperature you actually want and reducing the amount of cold water mixed at the faucet.
Furrion Water Heater Isn’t Getting Hot Enough
First, make sure you’re actually dealing with a heating problem rather than a flow problem.
Check the controller’s temperature setting.
Then consider the incoming water temperature. Very cold inlet water requires the heater to produce a larger temperature rise.
Elevation can also affect propane-appliance performance. If you’re operating at high elevation and the problem only occurs there, consult Furrion’s recommendations for your specific model.
Resetting a Furrion Tankless Water Heater
A reset can clear some temporary faults, but it shouldn’t become the repair.
For FWH09A-series units, Furrion’s troubleshooting documentation instructs owners to:
- Turn the water heater’s power switch OFF.
- Wait approximately 5 seconds.
- Turn it back ON.
You can also stop and restart the water flow when appropriate.
If the same error immediately returns, don’t keep resetting the appliance. The code is telling you that the underlying condition is still present.
Most Common Things to Check Before Calling for Service
If I were approaching a Furrion tankless water heater with no hot water, my basic troubleshooting order would be:
1. Water flow
Is there strong, steady flow through the hot-water side?
2. Propane
Is there propane, is the valve open, and do other propane appliances work?
3. 12-volt power
Does the controller operate normally?
4. Error code
What does the controller say?
5. Exterior vent
Is the exhaust obviously obstructed?
Those five checks can quickly separate an RV plumbing or supply problem from a problem that actually requires water-heater service.
When to Book Service
It’s time to have the Furrion water heater professionally diagnosed when:
- E0 repeatedly returns.
- E1 persists despite a known-good propane supply.
- E2 returns after resetting.
- E3 repeatedly indicates an over-temperature condition.
- E4 repeatedly returns.
- E5 remains after confirming the exterior vent is unobstructed.
- E6 continues despite good water flow and supply.
- E7 appears repeatedly.
- The heater has good water flow, propane and 12-volt power but still won’t operate.
- You smell propane.
- You see damaged wiring, scorching or signs of overheating.
- The repair requires opening or testing the propane system.
Service Call Prep
Before contacting an RV technician, write down:
- Furrion model number
- Serial number
- Error code
- Controller temperature setting
- Whether you’re using city water or the onboard pump
- Whether other propane appliances work
- Whether the problem happens at every faucet
- Whether the heater attempts to ignite
- Whether the problem is intermittent or constant
Also tell the technician if the problem changes when switching between campground water and the RV’s onboard pump.
That one observation can be extremely useful.
FAQ
Why won’t my Furrion tankless water heater ignite?
Start by checking water flow and propane supply. A tankless heater needs sufficient water flow to operate correctly, and the burner obviously cannot ignite without an adequate propane supply. If the controller displays E1 despite good propane supply and water flow, further diagnosis may be necessary.
Can low water pressure stop a Furrion tankless water heater from working?
Yes. Tankless water heaters depend on adequate water flow, and insufficient flow can cause poor operation or temperature-related faults. Check campground pressure, regulators, filters, faucet aerators and showerheads.
Why does my Furrion water heater work with the water pump but not campground water?
The campground water supply may have insufficient pressure or flow. A restrictive pressure regulator or water filter can cause the same problem. If the heater works normally from the fresh-water tank and pump, that’s a strong reason to investigate the city-water supply.
Why does my Furrion shower keep going hot and cold?
Changing water flow is a common cause. Other fixtures being used, low-flow showerheads, pressure fluctuations, restrictions, and excessive mixing of cold water can all affect a tankless heater.
Should I turn the Furrion water heater temperature up and mix in cold water?
Not necessarily. With an on-demand system, I generally prefer setting the heater closer to the temperature actually wanted at the fixture. This reduces the amount of cold water that needs to be mixed in and maintains stronger flow through the hot-water side.
Can I keep resetting a Furrion water heater to clear an error?
A single reset is useful for determining whether a fault was temporary. If the same error keeps returning, repeated resets aren’t fixing the cause. Use the error code to determine the next diagnostic step or arrange for service.
When a Furrion tankless RV water heater isn’t working, don’t immediately assume the heater has failed.
Start with water flow.
Then check the propane supply, 12-volt power, controller error code and exterior vent.
Those basic checks can solve — or at least identify — many problems without unnecessarily replacing parts.
If the heater works from the RV’s onboard pump but not campground water, pay particularly close attention to water pressure and restrictions. And if an error code points toward an internal sensor, gas valve, ignition component or safety device, that’s where DIY troubleshooting should stop and proper service should begin.
Related Articles:
- RV On-Demand Water Heaters: How They Work and What Owners Should Know
- Girard Tankless RV Water Heater Troubleshooting: A Step-by-Step Guide
- RV Water Heater Takes Too Long to Heat? Here’s What to Check First
- Water Heater Doesn’t Work On Propane
Written by Dan Harvickson (Founder of Last Mountain Tech) RV Specialist