🚀 go-pugleaf

    I'm trying to hack the interface to my furnace to allow it to be controlled
by my PC.  My thermostat, A Chronotherm III, has 5 wires going to it.  I was
able to to deduce from looking at the schematic for the furnace that one wire
is a common, one is to turn on the Fan, and a third is either to turn on the
flame, or to turn on both the flame and the fan (not sure).  The A/C was added
to the furnace as an option, and I can't locate a schematic for it.  I would
expect there to be a single wire to turn on the A/C compressor.  This leaves
that 5th wire that I can't figure out.  I would think that this is a standard
interface that someone in net land could tell me about.  Any help?

Bill Pherigo