I have a Goodman high efficiency gas furnace which is about 8 years old. It seems to be working fine.
I had it cleaned by a technician today. He observed that the flame stays on for a couple of seconds after the power is shut off and that this is dangerous and needs to be rectified. He recommends a replacing the control panel at around $450 for parts and labour. Is he correct?

Frankly I don't see the harm of a two second delay for the flame to shut off.

Contact Goodman tech support directly and tell them what is happening. They will be able to tell you if this is normal or not. I don't suspect the board, but maybe the gas valve. Or it may be completely normal.

I too suggest contacting Goodman but at the same time I think you have a salesman diguised as a service tech on your hands.

I agree completely, Grady. Salesman, or simply an under qualified tech. Im willing to bet that five out of ten techs are under qualified for simple trouble shooting and proper repair of residential heating/cooling systems. Heck, that may even be closer to 8 out of ten in certain areas. Even worse, I am certain that there may be a 10 out of 10 ratio in some small communities.

I contacted Goodman by email and got a response that the problem is likely to be with the gas valve rather than the control board.

Thanks for the update.

I agree completely, Grady. Salesman, or simply an under qualified tech. Im willing to bet that five out of ten techs are under qualified for simple trouble shooting and proper repair of residential heating/cooling systems. Heck, that may even be closer to 8 out of ten in certain areas. Even worse, I am certain that there may be a 10 out of 10 ratio in some small communities.

Do I hear 12 out of 10? Some are so bad they'd qualify as at least a negative 1.
Believe me. I work with one.

Ha, I know how you feel some days. It is hard to find good help and some just don't seem to be able to comprehend or learn. Got to catch them young and teach them I guess.