Hello, I have been reading about wood boilers for a couple months now. I think one would work well for me and be worth it in the long run. I have alot of questions, one thing that I have been having a hard time figuring out in my head is related to pressurized storage. I understand putting the hot from the boiler into the top of the tank, and returning the cool water from the bottom of the tank back to the boiler. Next, for heating a zone you take the hot off the top of the tank and have the return enter the bottom of the tank, this is what I'm trying to figure out. Is there not alot of weight from the water plus pressure to over come to push the water back into the bottom of the tank? Is this taking a big pump to accomplish or other forces at work to make this happen?