The old manuals recommended 15 or maybe 20-30 minutes on high after cat engagement for each load before turn down. Did they change the new manuals to "require" 30 minutes? After 15 minutes my flue temperatures are close to the redline and the cat meter is up past 1500 so I drop the stat at 15 minutes almost always. I've done the 1 hour on high thing to melt the goo and even though the meters all stay below the redlines (stat actually closes some) I am wasting tons of fuel, making tons of heat, and not really cleaning the firebox much anyway. I don't really get that clear exhaust plume until the stat closes down either by the stove getting really hot or by me selecting a normal cruise temperature which also closes the stat. Nonburners seem to like zero visible emissions more than the blue smoke of full throttle that occurs before the stat closes some.