[77newell]

I rebuilt the butterfly baffle actuators when I installed an electric vacuum pump to replace the compressed air driven one. That made a huge difference in my compressed air consumption.

I had a huge outside air draft coming from 3 sources; a warped entry door which I rebuilt, air leakage into the box containing the heating system which I sealed with foam panels, and air leakage where the hoses from the heater box penetrated the floor which I solved by stuffing foam into the gaps. I could have sprayed foam in gaps but that would make future repairs more difficult. I found these air leaks by turning on all my vent fans and watching airflow with an incense stick, and checked that they were gone by using the same method after corrections. There is no way for the heater to keep up when there are significant air leaks.

I found one reference to coolant heaters for buses rated at 45,000 btu/hr that assumed 7gpm and 13 degree temperature rise. The usage end would then be 7gpm and 13 degree temperature drop. These numbers sound consistent with what I calculated, though my numbers were smaller because the core design is smaller. Then again I haven't been involved in heat exchanger design in about 30 years so I could be off (that has been said about me a lot).

Forest: The cord is still there and should I find a nice lady to travel with I suspect she is the one that will benefit from the electric heat