I accept for consideration this good info. However I've been using it this way for several years without a shut down. Now, I'm wondering I am just finishing up insulating all the baseboard pipes running below the floor in the basement ceiling. Now that could even add to hotter water in the boiler. But how can the water possibly get any hotter than what it produces. That just doesn't seem to bare logic. If the boiler puts out say, I have no idea, just for comment 200F Then it's 200F when it leaves the boiler, there is no way it's going to return hotter? Just thinking about it. Thanks so much. I may have to open some of these vents. Haven noticed any problem heating the house however and it seems to heat up quickly.If the radiator gets HOT from closed covers, the water temp rises in the boiler and it will shut down on it's normal temp control so you accomplish nothing.