Potential consequences of improper installation could include: Electric shock. Blowing a circuit breaker. Damaging the thermostat unit, the electrical system or even the AC/furnace unit itself.

Will a thermostat work if wired wrong?

The connection of the wiring from the thermostat to the indoor unit control board could be incorrect or a wrong thermostat could be have been installed for the system. It only takes one wire that is incorrectly installed to not allow the system to work properly.

What happens if you touch thermostat wires together?

You Touched R and C wires. This causes the current in the circuit to be high, which may quickly overheat the wires. In a typical household circuit, the circuit would be protected by a circuit breaker (or fuse) which is designed to open (trip) to prevent damage to the wires in this situation.

Are thermostat wires interchangeable?

They can not be used interchangeably owing to myriad technical reasons. Just like this, a 2 wire thermostat can be either a line voltage model (operating at 120 V or 240 V) or a low voltage model (operating at 24 volts).

Can I change a thermostat without shutting off power?

The short answer is no, its not OK - you increased your risk of electrocution and thats never a good thing specially for a DIYer.