Seems I have encountered the loose exchanger tube situation. The curved tubes at the top have a small flange ring that appears to be caulked to the top of the heat exchanger box. the cleaning rod will not travel up to the top on the one side any more. The other side seems to be intact, but the caulking material is coming loose.I can see where ash has blown out of this area around this flange ring. What made me find this issue is that the fire bowl has been having an issue with lazy flame and a pellet buildup last year. If we didn't pay attention to this stove, we would get smoke in the house during thermostat shutdown. I will be pulling this stove apart to review the options and repair possibilities. Buying a new stove is not an option. Finding a Quadrafire authorized repair/service person has been a fruitless endeavor in the past. From other posts I've seen, these tubes don't look like they were swagged in place - more like epoxy caulked. Any comments or input would be appreciated.