Rob R. wrote:
I will remove the flue pipe and block the thimble, and will compare the coal consumption vs degree days over the next month.
From 10-29-16 to 12-17-16 I averaged .82 lbs of coal per degree day, and that was with the heat pump helping through November.
From 12-17-16 to 1-19-17 I averaged .78 lbs of coal per degree day, without the heat pump.
This tells me two things.
1. The efficiency of the coal heating system improves as the weather gets colder and there are fewer times when the entire system has to get heated up just to add a little heat to the living space - that was my reasoning for using the heat pump back in the fall.
2. Unhooking the flue pipe from the oil boiler seems to have little to no effect on the amount of coal I burn. Or, the effect is less than the efficiency improvement that comes with the colder weather and longer run times of the boiler.
I have decided to hook the flue pipe back up to the oil boiler and put it back into "ready for action" mode.