I have a 13 SEER heat pump about one year old. Everything's been working fine, but the AC suddenly started heating my house spontaneously (no changes to thermostat, etc).
The outside ambient temperature is 80°F but the incoming air measures 116° at the vent. The odd part is that the outside condensing unit is blowing 68°F (cold?).
What might be causing this?
Coincidentally, I've been meaning to install a Nest thermostat I purchased awhile back. If this is a problem with the thermostat, I would just go ahead and do the installation now. But if this is more likely a problem with the system, I'd just as soon have it repaired before changing anything.