I assume you are running on GAS..
On mine, when new, and cold, it took me several tries before it would work, Kept going to FAULT. I am assuming moisture was keeping the flame sensor (Thermocouple) from sensing. Eventually I had to replace the control board and that fixed it..
Spark gap adjustments are often off, and this can prevent ignition.
Those are my two best guesses.
IF it is lighting (you will see and hear) 3 times and then going FAULT. the control board or thermocouple are the culprits. DInosaur boards are superior to Atwood OEM.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times