I have a Nature's Comfort 250,000 BTU Wood Boiler and I can't seem to get it to work. The boiler burns the wood with no issues but the water just doesn't flow to the heat exchanger inside the house. The pump on the boiler works but I think the brazed plate heat exchanger is clogged. I have done some research into a shell and tube type heat exchanger but I don't know if they are too inefficient.. There was some corrosion inside the boiler and that probably made its way to the brazed plate heat exchanger and clogged it. I also am considering an in-line filter but not sure if this will restrict flow even more. Thanks for your help!