According to the internet, it should be a piece of cake to replace the back wall (refractory panel) of my fireplace. I have a Temco 42" Flush Face Heat Circulating Fireplace. But trying to get the front 3 metal panels off is a nightmare. I have removed all of the screws, but something is holding the top panel in place. It looks like it may be a spring that connects the flue arm to the panel itself. Does anyone have any experience with this particular model?