Originally Posted by keith_h
I'm still learning about these things but wouldn't the freezer getting down to -4 indicate that the heating systems are working correctly and that the problem is somewhere else?
And where might that "somewhere else" be?
The only non-commonality between AC and propane heat is the ability to transfer that heat to the ammonia.
Barring the OP doing something different between the two heat sources that causes radically different interior temperatures, I still think heat transfer affecting just propane should be looked at.
The freezer is much better insulated than the "ice box" and it gets first crack at whatever "coldness" is in the ammonia.
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