I have had my Vermont Castings Defiant wood stove with a catalytic converter for over 20 years. It has been great. I always start up the stove with a higher heat and then close the damper to cruise at a lower temp. Last year I noticed when the start-up temp was at the high piont, I could not close the damper. That scares me as I cannot turn down the heat and it keeps roaring away. So then I would just close the damper before it got that high. Someone mentioned it had become warped. Is this something repairable or is it just time to get a new stove? I mean, this puppy has never been / needed service work except the annual cleaning by my chimney sweep. I love it. Are the new stoves as dependable today? I imagine they are probably more efficient. Is the glass front I see now as good at heat holding efficiecy as the solid closed cast iron?