I have a Harman P61A freestanding stove that was installed into an existing fireplace. It is vented through the chimney. I know I have to get up to the top and take a brush to the vent pipe to clean it out. My question is, would I do the same thing for the vent pipe that is behind my ash pan? When I take the ash pan out, there is the combustion cover, fan and the flue that leads to the vent pipe. I assume it's safe to take brush and clean the insides of the the flue? I also know the ESP is in there and I need to be careful not to damage that as well...so am I correct in my assumptions? Thanks!