I've got a Munchkin Contender install with a homemade neutralizer on the condensate drain line as it discharges into old cast iron floor drain. neutralizer is full of aquarium-type crushed limestone. over several years I have had to make 4 or 5 service calls to clear the condensate lines of slime plugs - which I suppose to be a low-pH loving bacterial colony. the slime seemed to start out at the discharge of the condensate line by the floor drain but has made its way back up the system and is now (this morning) plugging the outlet from the condensate reservoir on the Contender. I doubt this is the only boiler to be plagued by this stuff. I would sure like to offer a long term fix to my client as we're both getting tired of this recurring.
only thing I've found in searching wall posts is maybe putting copper sulfate crystals into the condensate reservoir. any experience with that? (curious as to how much to use and how long it will last). any other approaches?