I have a carrier unit that is giving me trouble. When the power is applied the inducer motor turns on and the spark for the pilot begins sparking. After the pilot lights the burners come on and seem to burn fine however they only stay on for ten seconds at best. I am stumped because I have already put in a new gas valve, three wire pilot assembly and rollout switch. I am writing asking for advice seeing as I am still fairly green in the field. I also dont want to keep throwing parts at this unit. Also customer doesn't want to replace unit at this time.