When all else fails, open the package and find instructions on how to replace. :/ Looks like the back panels have to come off, where the inlet/outlet is. That said, I will have to call the pool store. The heater is installed in a corner with very little room for maneuvering anything behind. I was bruised for days after wrapping myself around the heater, vents, and pipes trying to get that stupid little plug in there this spring. My guess is that they will have to pull the whole heater out. Grrr...