The past couple of days, it has been pretty cold in Western PA. I worked two 16 hour days in a row, and both days my Eko 40 was not reloaded until I got home, and it had burned out. The interesting thing is that my house was still warm, despite the fuel error message on the boiler. The pump on the boiler had shut off, but there is a secondary cirulation pump on the heating loop that still works when a thermostat calls for heat, and the boiler burning out has no effect on this pump. I was wondering why the house was still so warm even though the fire was out, and I got to thinking...the main loop goes through a sidearm heat exchanger on my domestic water tank. I wondered if the secondary circulator was pushing enough water through the main loop, boiler, and pex that the heated water in the domestic tank would actually heat the water in the heating loops, thus keeping the house warm. In this case, the sidearm exchanger meant to heat the domestic water would actually be working in reverse, and the domestic water would almost be acting as thermal storage of sorts. Does anyone think I am crazy, or is this possible?