Why does the AC come on when the heat is on max?

[weq92f]

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That's a fancy schmancy VA unit compared to mine but...I think the Gen IV had already separated the evaporator and heat core rather than using a single component for both. My earlier unit uses a single unit for both and allows a blending of the two via a sliding scale from hot to cold...which basically cycles the pump to achieve the desired blending.

I believe the later models allow this blending the same way, but it's accomplished with air blend doors. If you have the heated water inside the unit and the A/C compressor pressurizing the system simultaneously and all you get is COLD vent air, I suspect your system is malfunctioning if indeed you've got it set to C rather than F and you really are going for heat!

Whether its a software or a hardware fault, something isn't right!

-Kevin