"Kevin Moore" wrote in message
...
How hard is it to install a common wire?


Depends...you MIGHT have the 5th wire there...but normally, not.
You just have to pull an 18-5 stat wire from the unit to the stat, and then
wire into the common lead of the trans..



"Steve@carolinabreezehvac" wrote
in message ...

"Kevin Moore" wrote in message
...
I just bought a Honeywell Chronotherm III. Model Number on the box is
T8601C.

Here is a link for the instuctions that came with it:

http://hbctechlit.honeywell.com/tech...0s/69-0533.pdf

I'm a little confused on how to hook this up, although I think it
should
be
easy.

I have an old Lennox mercury switched thermostat. There are four
wires
coming from the wall, red, white, blue green.

Those are connected to the terminals on the old thermostat as follows:
Red-"R"
White-"W"
Green-"G"
Blue -"Y"

I tried hooking up this new (Digital) one with the same color to
letter
arrangement. The thermostat showed "AC" on the readout next to the
time.
The manual indicates it will do this ( and not operate the hear or
air)
until it gets power from the 24VAC system (It has battery back up,
which
is
how the LCD display works).

My house is Electric cooling, gas heat.

So, either I do not have 24VAC, or I hooked it up wrong. Any ideas?

Thanks for help,

Kevin



You dont have a "C" Wire ran to it, and until you do, its runnin on
batteries..
Most good digitals require 5 wires.
This one also does.