Florida heat pump -- no heat
It's quite the school but it's not impossible, I replaced my aging mechanical thermostat with a programmable digital one, the actual labor took a short afternoon, but I spent most of the additional time learning about the nonsense.
On the notes of electricity, I think most thermostats are 12v so I doubt there's much fear of getting shocked but I would turn off the main fuse to the heat pump if for no other reason than you don't want it kicking off / on while you're fiddling with the thermostat.
I can tell you that you will need to know the manufacturer of your thermostat (such as Honeywell), also whether it has Emheat, and how many and what color wires there are. Since you'll likely have to pull the stupid thing off the wall anyhow, I recommend becoming familiar with the unit. Now there are usually two or four screws that hold it against the wall but before you get that deep you'll want to get the cover off and see if you can get the model number of the thermostat, also write down what color wire connects to what LETTER on the connector as well.
I forget exactly, but the letters are usually like Y, X, W, A, B, R... Weird and apparently totally unrelated but they all mean something, there might be a G also, and I think in some cases there is AB and Y2 or other such odd stuff, anyhow all of this information you want to secure before proceeding.... I think the wires are like green, blue, red, maybe black and yellow, not really sure because it's been some time but they're thin wires, almost like the ones inside your exterior telephone box.
By this stage you might be able to download or obtain a user's manual from the manufacturer's web site as well.
Last edited by 8307c4; 11-06-2007 at 01:14 AM.