I am installing a programmable thermostat (upgrading from a previous programmable that wasn't to our liking.

When taking the old thermostat off, I noticed 4 of the 5 wires were labelled. That's a good thing. HOWEVER, when I took the old baseplate off, 2 of the labels fell off (not sure from which wires.

My new thermostat requires:
RC
RH
G
Y
W

The wires from the wall are:
G - green
W - white
? - orange
? - black
? - red

So, I need to "map" RED, ORANGE, BLACK, to RC, RH, Y.

Can anyone help me? I am at a loss here. The house is about 4 years old. If I can't get an answer here (or how to TEST which wires are what), I might ask a neighbour in the same style of home (same contractor) to see their wires which are hopefully labelled.

THANKS!

ONLY IF four wires were hooked up to the old thermostat. Hook the R to RH and jump the RH to the RC. Now its either the orange or the black wire. Touch each one to the red wire. Connect the one that turns the outside system ON when touched to the RED wire to the "Y" leave the other unused.

Thanks for the reply.

I had 5 wires in the old thermostat.

I knocked on my neighbours' door and checked her thermostat - got my colour/label mappings that way. Everything is working fine now.

Thanks for the help though!
Eric