Girard Tankless Water Heater Error Codes Troubleshooting Guide

The most common Girard Tankless Water Heater error codes that users most often encounter include E0, E1, E2, E3, E4, E5, E6, E7, E8, E9, En & Fd. 

Basically, these are the diagnostic error codes from the controller corresponding to an ongoing unsafe condition throughout the system. Each of the errors refers to the specific malfunctions of the unit that require different troubleshoots. 

Resetting the heater can eliminate the error from the display at most times. But, without properly dealing with the root reason, you can’t get your heater back into normal operation.

Thinking that, I’m here for you bringing all effective fixes for each Girard error, highlighted with the exact meanings & reasons through this comprehensive guide. So, keep on reading till the end. 

Girard Tankless Water Heater Error Codes [11+ Easy Solutions]

I can understand how annoying it is that you’re enjoying the hot water in a chilly winter and suddenly an alarming message appears and stops the heating process. So, look no further! 

Go through our complete list to track down the actual reasons for the most frequent error code to troubleshoot Girard tankless water heater issues instantly

Error Code #1. E0 

Girard Tankless Water Heater Error Codes EO mainly appears when there is an open circuit or short circuit condition detected in the water outlet temperature probe. It is a clear indication of the internal failure of the probe either due to a wrong wiring connection or the probe is defective itself.

A temperature probe in an RV tankless water heater is mainly designed to detect the temperature of incoming and outgoing water. Then it sends the report back to the control board.

In case, there is any wiring fault to the outlet probe, certainly it fails to send the right signal to the UCB and consequently, the controller triggers the E0 code on the display.

How To Fix:

First off, turn off the power connection to your tankless water heater. Remove the front panel and locate the outlet temperature from the inside. 

Ensure there is a good connection of all wiring to the probe. If so, now verify the resistance of the probe with the voltmeter to define whether there is an open or short circuit. Simply you need to replace the problem if you find no continuity in the voltmeter.

Error Code #2. E1

Girard Tankless Water Heater Error Code E1 on the display indicates an ignition failure or accidental flame off during ignition. Basically, if the control board detects the flame failure while the burner is operating, it de-energizes the gas valve within 0.8 seconds to start the new ignition process.

If the burner does not light, the control de-energizes the gas valve again for the next ignition attempt. In case, the burner does not relight after the three trials, the controller of the heater goes into Lockout Mode and triggers the E1 error on the display.

Anyway, there are a number of reasons for flame failure in an RV tankless water heater. Such as:

  • Insufficient fuel supply
  • Accumulated dirt or obstruction between the igniter and burner
  • Faulty igniter connection to the control board  
  • Or, the igniter is defective itself.

How To Fix:

Without worrying, go through the below simple fix to eliminate the E1 error from the control display and get back the heater into normal operation:

i. Check The Inlet Gas Pressure

First off, verify the inlet gas pressure in your tankless system. Make sure the tank is not empty and the gas lines are working well.  

Now, take a gas pressure manometer and identify the maximum inlet gas pressure from the gas valve output test port.

girard tankless water heater gas valve

There should be 1.5” WC on low heat and 7.8” WC on high heat for the proper operation of the water heater. In case you’re getting under the desired setting, increase the fuel supply from the gas regulator setting and ensure a good gas flow to the water heater.

ii. Inspect The Gas Valve Wiring

Remove the front panel and inspect the gas valve assembly. Higher chances are solenoid valves and the linear valves are not open.  That’s the reason, no gas is supplied to the burner orifice and an E1 fault code occurs. To check the integrity, do the following:

  • Locate the brown and black gas valve wires on the 8-pin wire connector at the bottom right side of the control board. 
  • Unplug the connector and pull out the wires.
  • Measure the voltage between the wires during the trial for ignition and it should have 12VDC. If not, you’ll have to replace the faulty valves or the wiring. 

iii. Check The Igniter Connection

Visually inspect the connection between the igniter and burner for any accumulated dirt or obstruction. Clean out the connection. When done, verify there is a spark at the tips of the igniter. If no spark occurs, check for cracks on the ceramic of the igniter.

Verify the distance of the igniter to the burner and fix it. Now, check the wiring connection of the igniter to find any damaged portions. Simply replace the faulty wiring. Unplug the high-voltage connection at the top right of the board and ensure the connections are good.

In most cases, you need to replace the whole igniter. Contact a professional for the igniter replacement. 

Error Code #3. E2

Girard Tankless Water Heater Error Code E2 is the indication of the flame sensing interruption during the normal ignition process. Whenever there is the Error code E2 on the control display, the complete heater goes to the Lockout mode. The error is almost similar to the error E1 and the possible causes are also the same.

How To Fix:

Follow all the above-mentioned fixes for Error E1 and hope that the code will diminish from the control display. If not, head to a professional to discuss further troubleshooting.

Error Code #4. E3

Girard Tankless Water Heater Error Code E3 appears on the control panel when the ECO thermostat opens before ignition or during normal operation. Under normal circumstances, the error mainly occurs when the outlet water temperature of the heater exceeds 79°C. 

Emergency cut-off is mainly a safety switch of the heater that is designed to turn off the unit at 140 degrees. Thus, when the water reaches a very high temperature, the ECO opens and shuts off the unit to prevent further damage or harm to the system. 

The control panel waits approximately 15 seconds for a normal situation and turns off the burner and fan immediately.

The major reasons for an overheated tankless water heater include:

  • Improper thermostat setting
  • Faulty thermostat
  • Restricted Airflow
  • Low water pressure 
  • Restrictions in the inlet or outlet water control valves
  • Or, malfunctioning of the water temperature probe. 

In most cases, the error is mainly related to the malfunctioning of the ECO. Either there is a wrong wiring connection to the switch or the element is defective itself.

How To Fix:

Follow the below step-by-step procedures to eliminate the Error code E3 from your Girard tankless control panel:

Step #1: First off, unplug the water heater from its electrical supply and turn off the hot water faucet. Wait for 10-15 minutes and then turn on the heater again.

This will reset the control panel and the error code should be diminished. If not, proceed to further troubleshooting. 

Step #2: Check the thermostat for your recent temperature setting. Ensure it is set to the recommended temperature level. Also, ensure the thermostat is in well working condition.

Step #3: Inspect all the air vents of your heater for any obstruction. Clean out the stuck debris from the vents to ensure a fluent airflow. Don’t forget to clean the inter air filter screen as well. 

Step #4: Ensure there is good water pressure in your water pressure. If not, increase the supply from the water pressure regulator.

Besides, make sure the water control valves of your water heater are free of any restrictions. In most cases, malfunction of the water temperature probe leads to heater overheating. So, it’s better to verify this major element as well while fixing the E3. 

Step #5:  If still in the same situation, be sure it is time to visually inspect the ECO. Locate the ECO from the back right of the unit. Now check the ECO as follows:

  • First, inspect wire connections on the ECO. There would be clip-type spade connections. Ensure it is firmly connected to its place. To do so, pull back the insulation over the spade connection and then push the clip down.
  • Verify the resistance of the ECO with a voltmeter.
  • If needed, Jump ECO to ensure that is working well. If not, you need to replace the ECO.

Error Code #5. E4

Girard Tankless water heater error code E4 indicates that there is something wrong with the water inlet temperature probe. The inlet temperature probe has failed either due to a faulty wiring connection or any internal defects.

When the controller of the tankless system detects an open or short circuit to the probe, it immediately shuts off the heater and throws the E4 on the display as a diagnostic error code. 

How To Fix:

Before inspecting any internal element of your tankless system, it’s always advisable to turn off the electric supply to your water heater. Locate the water inlet temperature probe from the inside and verify the actual fault going through it. 

First, make sure there is a snug wiring connection to the heater. If needed, check out the continuity of the probe with a voltmeter. If you are getting the probe beyond any repair, you need to replace it to eliminate the E4 from the Girard tankless water heater control panel. 

Error Code #6. E5

Girard Tankless Water Heater Error Code E5 is the indication of the failed blower motor of the unit.  Every Girard tankless water heater features a 4-wire variable speed brushless motor that is designed to operate with a 24VDC pulse width modulation system.

It is an essential element of a tankless system that mainly exhausts gas through vent pipes and helps to continue the ignition process by sending a signal to the control panel. 

In case, if there is a wiring fault in the motor connections, it will fail to send the signal to the board. When the controller doesn’t find any single from the blower motor before ignition or during normal operation, it shuts off the unit and triggers the E5 code on the display.

Despite the faulty wiring, the motor starts malfunctioning due to stuck debris on the assembly. In most cases, the shut-off water flow icon at USP leads to Error E5 on the Girard tankless models.

How To Fix:

  • Locate the blower motor assembly from inside the heater. First off, you need to check the blower motor wiring to the control board. To do this, verify the CN1 wire connection at the control board. Ensure it is in a well-working condition and also the motor is properly grounded.
  • Now check for debris in the blower assembly and clean it.
  • Then, locate the water flow icon at the UCP and make sure it is turned on.
  • In any case, all the wiring connections are good and the water flow icon but still the blower motor isn’t operating, be sure the control is defective and it needs urgent replacement.

Error Code #7. E6

The E6 error code on the Girard tankless water heater is mainly signing you the over-exceeded temperature of the outlet water. Mainly when the outcome water temperature has exceeded 140°F or 60°C and stays for about 3 sec, the control board sets an error code E6 on the display. 

This error is almost similar to the E3 error code, relating to the exceeded outlet water temperature.

How To Fix:

Here are the simple fixes you need to apply to adjust the water temperature:

  • First off, reset your water heater either from the control panel or from the circuit breaker where your heater is connected. Unplug the power connection and turn off the hot water faucet. Let the heater rest for about 10-15 minutes, and then simply turn the electric and water supply on. 
  • Then, set the thermostat. The recommended temperature from the user manual is within 15° (F). Also, ensure the thermostat is working well.
  • Inspect the air vents and air filter screen for any blockage and clean out the stuck debris. In short, you need to ensure a fluent airflow to the entire system.
  • Above all, don’t miss adjusting the water pressure as the water temperature of the heater automatically rises when the pressure is too low. So, head to your water pressure regulator and turn the screw clockwise to increase the pressure. 

When done, you can expect that the annoying Girard tankless water heater error code E6 from the control display is diminished.

Error Code #8. E7

Girard tankless water heater error code E7 indicates an open circuit or short of the linear valve. When the controller detects that the liner valve isn’t responding well before ignition or during normal operation might be due to a short circuit, it triggers the E7 on the controller as a diagnostic error code. 

Either there would be simply a faulty wiring connection or the defective valve is the culprit itself. As for the solution, we’ll inspect the valve assembly and check out all the wiring connections there. So let’s proceed:

How To Fix:

First off, locate the liner valve assembly and check the connection of the white and red wires on the 8-wire plug. Make sure there are no glitches in the connection. If yes, fix it.

Now, unplug the connection and measure the resistance of the coil of the linear valve by setting the probe at the white and red wires of the 8-wire connector. It would give a reading of approximately 85 ohms. If not, be sure the valve is faulty and you need to replace it. 

Contact the Girard customer support center or a professional to perform the replacement tasks for you quite effectively. Or, you can go through the below-suggested procedures to replace the faulty gas valve by yourself. But to do so, you’ll need to have a replacement part.

How To Replace Faulty Gas Valves On Girard Tankless Water Heater?

Go through the step-by-step procedures as the following:

Step #1: Turn off the power supply to your water heater. You can do it from the power switch or through the circuit breaker.

Step #2: Inspect the fuse and then remove the 15 mm nut from the fuse holder. Pull the fuse holder and wires out. 

Now disconnect the input power connector and detach it from the control board.

Step #3: Remove the wire connectors from the control board. Now locate the firewall from the inside that is holding the blower housing, gas valve bracket, ground, and gas test port. 

You will find 2 Phillips screws on the top. Unscrew them and then you can easily lift the firewall from the gas valve bracket.

Step #4: Now take a 19 mm or 3/4 inch wrench and remove the gas line from the orifice block. Then unscrew the gas input fitting from the bottom three screws.

Step #5: Disconnect the gas valve bracket and pull it out. When done, remove the input and output gas lines from the gas valve.

Step #6: Finally remove the bracket from the original gas valve and place it on the new valve. Now, reassemble the new valve by reversing the above process. After installing the new valve, don’t forget to check for leaks from the valve assembly. There shouldn’t be any gas odors coming out from the assembly.

Error Code #9. E8

Girard tankless water heater error code E8 is mainly signing you the faults in the air pressure switch. If the control board fails to sense the air pressure switch for 7 seconds before ignition and is cut off for 3 sec during normal operation, it triggers it as an error on the display. 

An air pressure switch on any water heater is basically designed to maintain constant air pressure on the entire system. In most cases, the switch also acts as the pressure safeguard that prevents the buildup of toxic gasses within the appliance.

Anyway, if there is any faulty wiring that goes to the switch, the controller fails to receive the signal from it. Despite the faulty wiring, other major reasons for pressure switch failure include:

  • Insufficient airflow
  • Failed blower motor
  • Improper resistance to the switch
  • Or the switch is broken itself. 

How To Fix Air Pressure Switch Failure In The Girard Tankless Water Heater?

Here are all the effective steps to follow to fix the air pressure switch on your RV tankless water heater:

Step #1: Inspect The Blower Motor 

As for the first step you need to inspect the blower motor as higher chance are the blower motor has failed, leading to poor airflow throughout the unit. To do so:

  • Check the wiring connection of the blower motor for any damages. For instance, locate the CN1 connection at the control board and make sure there are no defects.
  • Now, clean out the debris in the blower assembly. Also, the blower should have good power and be properly grounded.
  • When done, verify the continuity of the Petit Tube in the blower housing using a voltmeter. Make sure the mounting nut is tightened enough and the standpipe is not twisted out of position. Also, the petit tube in the blower housing should be facing away from the blower wheel. 

Step #2: Clean The Air Vents

In this step, head to the all exhaust vents of your water heater. The air vents of a gas water heater tend to get clogged due to stuck debris from the combustion. It’s always essential to pay close attention to proper cleaning for the heater venting as the buildup of leaves or other materials could catch fire.

Anyway, inspect the exhaust vents and start cleaning using a vacuum cleaner that is connected to an extension. Insert the vacuum hose and vacuum up as much as you can from inside of the vents. 

Along with the venting, don’t miss to clean the air filter screen of the heater. It’s also quite easy! Simply unscrew the air filter from its place and clean it under running water.

Step #3: Check The Air Pressure Switch

Access to the air pressure switch by removing the mounting screws of the component. To check out the switch, do the following:

  • Take a voltmeter and check out the continuity at the switch hose connection.
  • Then, verify all the wiring connections of the switch to the control board are in well working condition.
  • Inspect the open pipe of the pressure switch for any stuck debris. Clean it.
  • In case, still you are getting the air pressure switch non-functional, you need to replace it with a new one.

Error Code #10. E9

Girard tankless water heater error code E9 is the clear sign of the shorted or open flame sensor. Basically, when the flame sensor or the wiring has shorted with the contact of the burner, the controller senses it and throws the error E9 on the display.

How To Fix:

First, locate the flame sensor probe of your tankless system. You will find it at the right-hand post of the igniter assembly that will be wired with the control board. 

Now verify if there is a short in the flame sensor probe or its wiring. If so, repair or replace the defective part.

Error Code #11. Fd

Girard tankless water heater error code Fd appears on the control display when the system operates with the winter-use device. All the Girard tankless water heater models equip a WUD Thermostat. It is basically an anti-freeze element that keeps the water heater from freezing when the RV is operating under freezing conditions.

This bi-metallic thermostat is designed to turn on at 35 degrees Fahrenheit and turn off at 48 degrees Fahrenheit. Thus when the thermostat turns on the water heater will begin to operate and heat.

The controller will also keep the ignition process on until the temperature reaches 48 degrees. At this point, the flame shuts off immediately and the fan turns off 30 seconds later. 

And when the WUD thermostat is engaged by turning on the water heater, the controller will keep showing the “Fd” code on the display.

How To Fix:

As your water heater is running under the operation of the anti-freeze WUD thermostat, no troubleshooting action is required. It will automatically diminish when the temperature reaches the recommended level.

Error Code #12. END/EN

END or EN error on the Girard tankless water heater is mainly a system timer. When your tankless water heater runs longer than 20 min, the controller automatically turns off the unit and shows the “END” or “EN” code on the display. 

It is basically a safety feature of the system. Thus, no action is required to eliminate the code. Just turn off your unit, turn off the hot water faucets, unplug it for some time, and then turn it back on. Hope that you will start getting hot water again.


What to do if there are no sparks in the igniter in my Girard tankless water heater?

If no spark occurs, you need to check for cracks in the ceramic of the igniter. Verify the wiring connection. Then, unplug the high-voltage connector using insulated pliers and hold it approximately 1/8” from the case. Now look for the spark!

Why does my Girard tankless water heater not start up when the faucet is turned on?

First off, check for the fault code. If not, make sure the heater on/off switch is turned on. Test water flow and confirm that water lines are connected properly. If the water flow is less than 1 GPM, increase the pressure or replace the faulty flow sensor.

In Closing

After complete discussion, it’s worth mentioning that this is an ultimate guide on all the Girard tankless water heater error codes. Throughout this guide, I’ve explained nicely how you can easily clear the error code and start getting the hot water gain. 

Hope that all have become enough informative for you. Still, if you’ve any confusion left over in your mind, don’t hesitate to share your thoughts with us through comments. I’ll guide you with the best solutions. 

Lastly, I’ll recommend operating your Girard tankless water heater under regular maintenance if you want to avoid such unwanted trouble codes and to run your heater with its optimal performance and efficiency!! 

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