A couple of months ago I posted on how everyone should clean and check their wood stoves for leaks before the heating season. Mine was clean and ready, and I didn't think it had any leaks - until I discovered one last night.
I only fire it up when it gets below zero to save on propane, so with temperatures forecast to get down around ten to fifteen below and winds at 25-30 mph I thought I had better stoke up a nice fire.
A few hours later the fire was burning nice and hot, but my wife said she could smell an occasional whiff of smoke. I checked the dampers and vents and everything seemed fine, so I sat and watched the stove and pipe and sure enough - a short puff of smoke came out from where the flue damper was. The wind was strong enough to overpower the hot smoke and the pressure buildup caused the leak. I will need to replace that section of pipe, but in the meantime I will try to find some high temperature putty or tape as a solution for the winter.
I guess the moral of the story is; don't assume your stovepipe has no leaks until you watch it in windy conditions or test it under pressure.