I have 2 drain pipes on my, new to me, 2006 270 bhs tt. I would guess one is for the clean water tank. What would the other be for? It seems like maybe the hot water tank? Would I use that to drain the tank instead of removing the threaded plug for winterizing?
My guess is you actually have three pipes below the membrane. Two close to each other - one for hot and one for cold "low point drains". Used for draining the lines prior to winterizing. The hot one will NOT drain the W/Htr. The other one is near your water holding tank and is used for draining the water tank (although it won't drain completely..