I am attempting to remove the back cover for an annual cleaning, first year owning this pellet stove. I removed all the screws according to the manual, but the top edge of the back cover will not move. I looked inside the pellet hopper and I don't see any screws that should be removed. I did see some type of sealant on the top edge of the cover. Is this cover just stuck on with this sealant ? If so how do I remove the cover without damaging it. Or am I missing some screws somewhere. I was going to contact the dealer but that is hit and miss at best. Thanks for any help!