My IH tech would not install the IH thermostat as my HVAC system is heating oil/heat pump/AC system with 8 wires connecting to the current thermostat. Our installation was during the winter and the tech didn't want us to have something happen and go without heat - which I'm in total agreement with. I understand that he's not a HVAC tech so I don't have an issue with him not connecting it but... he couldn't advise me what wires should go where -or- if the IH thermostat would even work for me.
Is there a wiring guide available and I can try this myself?
This is what I used to hook mine up. I feel like the Time Warner rep that setup my account over the phone did a bait and switch one me. He told me the tech would set everything up and when the tech came out, much like your issue, he said I'd have to have an HVAC guy do it. I found this diagram and it worked for me. Good luck, hit me up if you have any other questions. I'll help as much as I can.
Contact an HVAC technician
There are multiple wiring configurations if more than 5 wires are used and some will burn out the thermostat and the furnace if it has electronic controls.
Especially true if the a/c was added to an old furnace
I have Propane a/c heat pump and the stat is intelligent running a relay bank in the furnace call a hvac tech no one else !!!!!!! There are many different systems out there