Underneath the Voyager are a four metal pipes. One is feed from the diesel tank to the underfloor heater, one is exhaust for it to purge burnt fuel and the other 2 are water send and return. They cost mega bucks to replace, even second hand. The water pipes do rust, and can spring a leak. I have cut both of these pipes leaving enough metal to fit rubber heater hose.Works well. Time will tell.