I have been using my Maxim M250 for just over a month now. It works great and I do feel the heat when the temperature outside is around 25 degrees or higher. The problem is when the temps dip below 20 degrees, which does happen every few weeks or so. When that happens, I just don't feel the heat in the house even though I have installed brand new windows, the thermostat claims the temperature inside the house is 68 degrees or so, and the water temperature on the Maxim says 190F. What am I doing wrong? Is it the house? the Maxim? or what?