I would say if you have tried to reset it and the lights are still there, the sensor is actually detecting flammable vapor. Do you have anything nearby like gas, or ammonia, or anything that might be confusing the sensor? If not and the reset isn't working you may have a bad sensor.
Below is the sensor test procedure to rule that out
The self diagnostic test has
detected the presence of
The Intelli-Vent control is
programed to lock-out and
display this error code if the
resistance value it senses from
the FV sensor is above 70,000
ohms but remains below
The Intelli-Vent control is in a
hard lock-out condition that
cannot be reset by cycling power
to the water heater. See the
instructions below for the reset
1 Turn off power to the water heater. Carefully check
the surrounding area for any substances such as
gasoline, paint, paint thinners, or cleaners that could
emit flammable vapors. Remove anything that can
potentially emit flammable vapors from the area and
store it properly in a different location.
2 Ensure power to the water heater is turned off.
Remove the FV sensor from it's bracket on the base
ring of the water heater and disconnect both wires to
the sensor. Take a resistance reading between the
two wiring terminals of the FV sensor and note the
Perform this test once in the area by the water heater
and a second time outdoors after allowing the sensor
to acclimate to the outdoor atmosphere for 5
Service Note: These resistance readings should be
taken using an ohm scale above70,000 ohms.
3 If the resistance of the FV sensor is above 70,000
ohms during the indoor test only and the resistance
reading taken in the outdoor atmosphere dropped
below 70,000 ohms. Re-check the area surrounding
the water heater for substances that could be
emitting flammable vapors. Remove any such
substances from the area and store them properly in
a different location. Repeat step 2.
4 If the resistance of the FV sensor is above 70,000
ohms during the indoor and outdoor tests - replace
the flammable vapor sensor.
5 If the resistance of the FV sensor was below 70,000
ohms during the indoor and outdoor tests and all the
steps above have been performed - replace the