flam will nor stay lit

This is typically going to be an air flow issue. With the vent off the back of the unit are you getting good air flow out of the dryer? You could have lint build up in the duct of the dryer somewhere or the blower wheel is broken, both of which will prevent good air flow and cause your unit to short cycle the heat. Please check your model number again. It appears it is not correct. I have attached some videos for you on this issue.

Hello, have you seen the flame? Did you check to see if the high limit thermostats on the burner house are not tripping? the high limits will cut the flame if they are failing but you have to get to them when the dryer flame shuts off early. With everything you have changed i would do the high limits.