Gas Pressure Error Code: CO and Improper Installation on a 20H Liquid Propane

A customer with a 20H-LP reached out with an error code showing “CO” on their controller (remote) and the water heater is not turning on.                                      


Upon checking the customer’s photos of their setup, it was noticed immediately that they were using a 20-lb propane tank with a regulator that is not recommended for gas installation. The picture below demonstrates this.

CO install.png

We also noticed the gas hose connected to the regulator and propane tank may not be enough to support the installation of the 20H-LP model. The 20H-LP requires a minimum of a 150,000 BTU gas line for it to operate properly. We recommend a ¾” steel or ¾” flex gas line capable of supporting 150,000 BTU or more. The picture below demonstrates this.

        CO gas line.png      CO closeup gas line.png


Eccotemp does not recommend using a 20-lb propane tank for this type of gas line or regulator because a 20-lb propane tank can have as much as 200 psi of gas pressure. The 20H-LP only requires a maximum of 11” water column and/or 0.5 psi. ***Some installations may require a step-down regulator to achieve the 11” water column and/or 0.5 psi.

After advising the customer about the parameters, which they followed, the water heater operated properly.

In order to avoid any installation issues, Eccotemp recommends hiring a professional/licensed plumber or gas technician experienced in tankless water heater installations to ensure everything is done correctly and in compliance with local regulations. We also offer pre/post-sale product consultation to provide you with the essential aspects of the tankless water heater installation. To schedule a call, please go to our Booking Page

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