Furrion Tankless Water Heater Troubleshooting (Complete Guide)

Furrion tankless water heaters are not for the faint of heart. Despite the popularity of these RV heaters, they can be difficult to troubleshoot when something goes awry.

Common problems with the appliance include frequent leaks, heating difficulties, and poor protection against freezing. Fortunately, error codes can give you an idea of what needs fixing, and sometimes all you need to do is perform a reset. Other times, you need a technician.

Furrion tankless water heater

This troubleshooting guide should provide the answers you need for a unit experiencing technical troubles. It will describe the challenges you may encounter, the causes of those challenges, and potential solutions. 

What Are the Common Problems with Furrion Water Heaters?

Furrion has a compact design suitable for most RVs and small spaces. Furthermore, it is easy to install, making it an excellent choice for new users. What could go wrong?


A leaking RV water heater is not always a cause for alarm. Most times, the pressure valve releases extra water when the internal pressure is high, which isn’t too big a deal\. 

However, a leaking drain plug or fitting is worth worrying about. Drain plugs are plastic and may wear down with continuous use. 

A leaking water tank is a worst-case scenario since it may explode due to high pressure and temperature. Sometimes, the water tank leaks after de-winterizing the unit. 


Sometimes, the water supply pressure is the culprit. If so, adjust the inflow water pressure to a maximum of 65 PSI. Likewise, replace all defective drain plugs or fittings and ensure you get the correct specification. 

Frozen Unit

This is quite a common issue with RV Furrion water heaters. These models feature a vortex technology that mixes hot and cold water in the required proportion for a consistent water temperature. The mixing bowl at the top of the t-flange is responsible for this process. 

However, it is also the reason for freezes. These freezes are yet another culprit of frequent leaks after de-winterizing the unit. Water expands at low temperatures, causing any residual water in the bowl to expand and escape through worn drain plugs. 


Furrion water heater

The manufacturer recommends adding antifreeze to the bowl before winter to solve this issue. 

While this is quite simple, it is difficult for users to displace the antifreeze when it’s time to use it again. Therefore, you should use a non-toxic antifreeze. 

Also, plan to add an additional one liter of antifreeze to the unit. You may use a bypass to avoid passing the antifreeze through the unit. 

Takes Too Long to Heat Up

There are three possible reasons for this problem: Either the incoming water temperature is low, or a partially-closed gas valve is preventing the unit from reaching temperature. 

In addition, the water flow could be more than the unit’s output capacity. Most Furrion RV heaters have an output capacity of 2.4 gallons per minute. 


Start troubleshooting by checking the gas valves and opening them to increase the temperature. Next, move to the water supply/control valve to adjust the flow rate. 

Note: It takes longer for water to heat up in high altitudes due to low oxygen levels. However, the appliance can still function at altitudes of up to 4,500 ft.

BONUS: Unit Won’t Start + Solution

The thermostat is often the culprit if the unit won’t start at all, provided there’s no obstruction in the gas and air inlet valves. 

First, examine the gas valve and the air inlet, using a long-handle flexible brush to remove all debris. 

Next, move on to the thermostat. Unplug the unit and switch off the water and gas supply valve. If disconnected, you may need to replace the thermostat or reconnect it to the unit.

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How to Troubleshoot Error Codes in Furrion Water Heaters

Furrion water heater models like the FWH09A display error codes to indicate specific technical issues. Here are the most common error codes you will find in Furrion models.

E1 Error Code

The E1 code on a Furrion water heater indicates an insufficient gas supply passing through the gas valve. It may also suggest that the gas reserve is empty. 

To solve this issue, confirm that the tank has adequate fuel and that the gas valves are open. Call a licensed technician if the error code persists.

E2 Error Code

Furrion tankless water heaters will display the E3 code when the temperature sensor malfunctions. Resolve the E3 code by letting out cold water for 10 to 20 seconds before restarting the appliance.

E5 Error Code

Furrion water heater models will display E4 error codes when there’s a problem with the air pressure. The code may indicate a blockage in the exhaust or a wrong wind direction blowing into the exhaust. 

Resolve this code by removing all obstacles within the exhaust. You may need a long handle brush to fish out debris. If the exhaust faces high winds, move the RV or coach out of the high winds and restart the water heater.

E6 Error Code

The E6 error code on Furrion water heaters is quite common. These are the possible causes of this error:

  • Cold water surge in the system
  • Low water flow
  • Insufficient water supply
  • Incorrect ratio of cold to warm water 

Thankfully, it’s pretty easy to fix these errors. For example, you can reduce cold water surges by reducing toilet flushes and opening cold water faucets. 

Regulate the cold water mix ratio by closing outdoor faucet valves and fixing shower heads that are leaking cold water to the hot side. 

For insufficient water supply, confirm whether the water tank is full or the water valves are fully open. Check the faucets in the case of a low water flow. 

Some faucets are designed to conserve water and may be responsible for the low flow. As such, ensure the taps have a minimum flow rate of 0.32 gallons per minute. 


Save yourself unnecessary trips to and expenditures at the repair store: Take note of these solutions and implement them to increase the lifespan of your heating unit.