I've made a big mistake and need some advice!

For some unknown reason, I thought it would be a good idea to remove my old thermostat without marking the wires, before trying to install the new one. Now I'm lost!

I live in a condominium high rise with a gas forced air furnace that I can't access. Once the thermostat wires go into my wall, there is no way I can trace them.

Is there a way I can figure out which wire is which? (I'm on a 9-wire set-up), or do I need to call a professional?

Sandra

Call a pro. With 9 wires you have to know for a fact they actually followed a standard color code when it was installed. Where is this furnace actually located, someone has to be able to acess it for routine servicing.