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Installing New Thermostat

Jbaha14
Jbaha14 Member Posts: 8
in THE MAIN WALL
I'm going to be installing a new thermostat this week and had a question regarding the wires.

Let me start by saying that I have a one-pipe heating system in my house. The old thermostat is a Honeywell CT3500. I bought a Honeywell TH8110. The old thermostat has wires labeled as R, C, and W. There is also a 4th wire coming out of the wall. This wire is not connected to anything and is not labeled (the wire is wrapped with black tape.) The wire happens to be green and I know that color means nothing but maybe it will help.

My question is this. Do I need to worry about the 4th wire? If so, where 8110 would I connect it?

Thank you to anybody who will be able to help me with this question.

Jason

Comments

  • Jbaha14
    Jbaha14 Member Posts: 8
    Honeywell VisionPro 8000 TH8110 Settings

    I installed a TH8110 thermostat today. I had wires R, C, W but had another wire that I did not install. I am wondering if this wire is responsible for the fact that I did not get the chance to set the number of cycles per hour (Installer Setup Number 240.)

    If anybody has any idea about this I would greatly appreciate any help you can give me.

    Jason
  • BillW@honeywell
    BillW@honeywell Member Posts: 1,099
    Wiring

    Do you have heat only? Use the "conventional" wiring designation(inside) terminals. If so, connect "R" to the "R" terminal on the stat. Note that there is a factory applied jumper between R & Rc. Make sure you keep that there. Connect "W" to the "W" terminal on the stat. You're done. I assume you installed the batteries, so the stat is powered. From the "home" screen, press the system key. Five blank touch keys will appear between the Done & Cancel keys. Press & hold the two blank keys on either side of the center blank key for about 5 seconds.The user set-up screen will appear.you'll see two sets of numbers, 4 digits on the left and two on the right. The center up/down arrow keys advance the installer setup memo. The right hand keys change the setting. Press the up keys to advance to number 0240. Press the right hand up/down keys to change the option to 1 for your steam system. When finished , press done. I'm leaving shortly, and won't be on the "Wall" for a while, if you need more info, go to www.customer.honeywell.com, and follow the prompts,or refer to the instructions in the box. Thanks for using our products.
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