The E6 and E7 error codes indicate that there is a problem with air flow. This can either involve the fan, the vacuum/air-flow switch, the connections between them, or an exhaust blockage. The FVI-12 manual has a labeled diagram of the internals of the water heater. You can also download the manual from our website if you cannot locate yours. Lastly, the comprehensive troubleshooting guide also has a picture with the components of the fan clearly labeled. You can download that at the link located at the bottom of this page.
If the fan is NOT coming on:
1. Verify that it has no physical blockages in the exhaust pipe which would cause it to not be able to spin freely.
2. Unplug the power supply from the water heater, remove the cover, and verify that the power connection going to the fan is secure. There is a black, square capacitor located down and to the right of the fan. This capacitor has two wires going to it. DO NOT, under any circumstance, touch those wires regardless of whether the water heater has power going to it. If after following these steps the fan will not come on and you are still receiving an error code, please contact customer service.
If the fan IS coming on:
1. Confirm that the exhaust pipe is clear of any obstructions and that it is not bent or damaged. You may also have E6 or an E7 error codes if you are experiencing strong, sustained winds.
If possible, try to protect the output of the vent pipe from strong drafts.
For the remaining troubleshooting instructions, the water heater should be unplugged so no electricity is going to it and your gas should be shut off.
You will need to remove the cover from the front of your FVI12.
1. Remove the two control knobs on the front by hand.
2. Remove the two screws on the top of the cover and two screws on the bottom.
Once those steps are complete, the cover can now be removed freely. Be careful as to not damage the digital display mounted to its front cover. This display can be disconnected by unhooking the black connector in the wires going to it.
Before moving forward, check all wires and wire connections inside the water heater to ensure nothing is burned or disconnected. There is a black, square capacitor located down and to the right of the fan. This capacitor has two wires going to it. DO NOT, under any circumstance, touch those wires regardless of whether the water heater has power going to it.
The air flow switch is a black disk located in the top left corner inside of the water heater. Locate the vacuum switch and confirm that the two wires leading to it are securely fastened. They should be plugged into the far right and far left connections on the vacuum switch. Next, you will see a rubber tube emerging from the front of the air flow switch and connection to the fan. Ensure that the tube is not kinked, pinched, perforated, or blocked with debris. If the tube appears to be in working order, pull the tube off of its connection to the fan and gently suck and blow back and forth into the tube. Should the diaphragm in the air flow switch be stuck, this will free it. You should now plug the display back up and place the cover back on the water heater. After reconnecting the power cord and opening the gas supply, please test to see if the water heater is now operating properly.
Should the issue persist, please contact Technical Support.
You can view our comprehensive troubleshooting guide for your Eccotemp FVI-12 Tankless Water Heater using the link below: