Important things to check before moving forward.
1. Is the Eccotemp FVI12 mounted vertically (straight up and down)?
2. Look at the right side of the FVI12 and you will see an information plate It will make mention of the gas type of this unit. Is that the gas type that you are supplying?
3. What is the gas regulator set at?
4. Have you sprayed the gas connection with soapy water for any leaks?
5. Is the FVI12 plugged in to a 120 volt wall socket or converter of equal voltage?
6. Are you above 6000 feet in elevation?
7. How much water pressure do you have? The FVI12 needs to have a minimum of 20 pounds per square inch.
8. How much water are you running through the FVI12? Maximum of 3.6 gallons per minute with a 35 degree rise is what the FVI12 will offer. For instance if the water is 70 degrees coming in you can expect about 3.6 gallons per minute of 105 degree water.