Digital Thermostat INstallation

[Kevin Moore]

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:

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

[Kath]

Which one are you trying to work with it? I think you need 5 wires for it to work both or you need a little jumper in the t'stat. Call the 800 number

[Greg O]

You need more wires! A T8600 needs a common wire. Greg

[steve]

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.

[Red Neckerson]

"Steve@carolinabreezehvac" wrote

Hmmmmmm....I C wot you mean........

[Kevin Moore]

How hard is it to install a common wire?

[steve]

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..