If you had a new system installed and it's not working right, forgive me, but the first step seems pretty obvious-call back the installer.

installer for sure

meanwhile maybe the thermostat is messed up or wired wrong.

I have a gas boiler separate from my AC in the attic and there are two sets of wires running (one from each unit) to the Honeywell setback thermostat. Heat and AC run separately from each other and are controlled by the normal thermostat controls. It sounds like your installer has connected the two systems together at the thermostat.

From what I recall, the heat only uses two wires, while the AC uses three. In most systems the heat uses red (power) and white (heat), and the cooling uses red (power), yellow (cool) and green (fan). At my thermostat the red wire for the AC (Rc) is on a different thermostat terminal than the red wire from the heat (Rh), but in your case they may have put them on the same terminal so that both systems power up at the same time.

Any decent HVAC installer should not find this unusual or hard to figure out.

Bruce

Just had our gas pack serviced, was told by the new technician that the contacts on the heat pump have started to show signs of rust. He said that when they go, the heat pump which provides our ac will either run all the time or not at all. That might help. But call the installer. We have twice a year maintenance with the install company and it has been great. Usually the techs replace things they see are starting to wear before they go bad.

It is better to see the system being installed. There might be problems on that.