Got a New Rheem 95% Dual Stage Furnace and 14.5 Seer R-410A A/C installed with a Honeywell Vision Pro 8000 touchscreen Thermostat.
The Furnace fired up ok and ran for 10 mins. When they turned on the breaker for the A/C lots of smoke billowed out of the vents! Real nasty smelly stuff. Every smoke alarm and detector in the house went off! After working on the problem for 45 mins ... the guys said the Thermostat WHITE Wire was shorting and caused both the Furnance and A/C to run at the same time!
And the smoke was only dust in the vents! They used a spare wire as the white wire and refused to change out the 30+ year old thermostat wire. Since it was after midnight I let them go and called their boss the next day ... they came back and replaced the wire.

So are these guys full of crap or what?
What really caused the nasty smelling smoke?
Any ideas?