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Eccotemp FVi12-Liquid Propane Indoor Tankless Water Heater E4 error code
Eccotemp FVi12-Liquid Propane Indoor Tankless Water Heater E4 error code
Updated over 10 months ago

Eccotemp received an email from a customer with an FVi12-LP tankless water heater shutting off after igniting and having an E4 error code. The customer has provided pictures of their water heater below.

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The image above demonstrates a correct and proper installation of the FVi12 Liquid Propane tankless water heater. Notably, the Blue Arrow (1) indicates the appropriate backflow preventer, but we advised the customer to ensure that there is a downward slope to prevent condensation damage. Regarding water connections, the Yellow Arrow (2) highlights the use of properly sized ½” water pipes. In terms of the gas connection, as denoted by the Green Arrow (3), a ½” connection is correctly utilized. Additionally, we have advised the customer to confirm that the gas pressure falls within the acceptable range, specifically between the minimum and maximum inches of water column.

The E4 error code for an FVi12-LP Tankless water heater indicates the outlet temperature sensor is not detecting the actual temperature of water in the hot water outlet. It can be caused by water corrosions that causes the Outlet Temperature Sensor to malfunction.

  • First, we recommended that the customer use a manometer to assess their gas pressure. They should ensure that the gas pressure falls within the acceptable range, as indicated in the right-side panel of the FVi-12 Liquid Propane tankless water heater for reference, between the required minimum and maximum inches of water column.

  • Second, we recommend descaling the water heater, particularly if the water supply has high mineral content or is considered hard water. Performing this maintenance task every six months is crucial to minimize the effects of corrosive elements and mineral deposits on the sensors. This routine ensures optimal sensor functionality, facilitates unimpeded water flow, and prolongs the lifespan of the water heater. To assist with descaling, we suggest using our Eccotemp EZ flush kit, a comprehensive solution that simplifies the process. Connect the kit to the water heater to maintain proper water flow within the pipes.

How we fixed the E4 error code for the FVi12 Liquid Propane tankless water heater.

After confirming that the gas pressure falls within the acceptable range (minimum to maximum inches of water column) and successfully descaling the water heater using the EZ flush kit, we recommend cleaning the outlet temperature sensor. This ensures the absence of corrosion on the metal sensor, preventing any interference with accurate temperature detection at the hot water outlet. For detailed instructions on addressing this matter, please consult the image provided below.

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Following the customer's completion of the troubleshooting steps outlined above, the FVi12 Liquid Propane tankless water heater operated seamlessly, and the E4 error code was successfully resolved. The issue stemmed from corrosions from the outlet temperature sensor, preventing it to detect the proper and accurate temperature of the water in the hot water outlet.

We always recommend taking advantage of our Free Pre/Post Purchase Consultation call with one of our experts to better understand the uses, installation, and common mistakes made when installing one of our products. We also always recommend hiring a professional licensed installer to ensure your installation is correct and intended for the product you purchased.

To take advantage of our consultation services or to schedule a call with one of our experts, please visit our booking page. Investing in professional installation and seeking expert advice ensures that you get the most out of your tankless water heater and enjoy reliable, energy-efficient hot water for years to come. Click here to schedule your call with our team today!

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