I just bought a house with a Harman PB 105 pellet boiler, and I'm getting it ready for the winter heating season. I figure I should start by cleaning/inspecting everything. I'm supposed to clean the tube heat exchangers once per week, but when I go to remove them, they're stuck fast. From the one video I found dealing with PB 105 maintenance, I see these should just slip out easily. I don't think I'm supposed to use a wrench on the bolts, am I? Any assistance appreciated! Thanks.