This is me second year with the Econoburn 150 and I am very satisfied with it's performance. There is one thing I've noticed this year that didn't happen last year. There as been some water coming from my blow-off valve/pipe that's located on top of the unit. It's usually not much. Looks kinda like someone spilled a cup of water on the floor of my building. Is this normal? Could the pressure in my expansion tank need adjusted? How much of a concern is this? Everything else seems normal with the boiler.