Ask Experts Questions for FREE Help !
Ask
    DIY's Avatar
    DIY Posts: 3, Reputation: 1
    New Member
     
    #1

    Jun 16, 2007, 08:18 PM
    thermostats for furnace and AC
    I am new to this site as of today.
    A contractor friend of mine and I just took out a 25-yr-old fuel oil furnace and 20-yr-old AC unit (central air) and replaced them with the following: Furnace-Maytag 95+ 2-stage gas furnace, and Maytag 16 Seer 2-stage R-410A AC unit. He is not certified to do electrical work. I've done most of my own wiring over the years but have never messed with this type of situation before. I've hard-wired in the furnace, and tomorrow plan on hard-wiring in the AC unit, complete with whip and shut-off box to be mounted on outside of house, as well as direct wiring the rest of the way into the breaker box.
    I have the following concerns. The old thermostat, which was a programmable digital, is being replaced with a Honeywell 8000 series, which is also a programmable digital. The old thermostat wiring consists of a red, a white, a green, a yellow, and a blue. Being this is a two-stage LP gas furnace, I am not sure how to run the thermostat wires. Will I need to get a 7-wire thermostat wire? Is such a beast even made? Or can I simply continue to use the current 5-wire thermostat wire? If the latter, how do I go about making the appropriate connections?
    On the AC unit, there are four 24V wires that are colored/labeled as follows: black = C, red = R, yellow = Y1, and blue = Y2. My understanding is that I only have to run the low-voltage AC wires to the terminal bar on the furnace, and not to the thermostat. How do I accomplish that task? Do I need only a two-wire cable, which is what the old AC had, or do I have to go with another 5-wire cable? What runs to what?
    Thanks so much in advance for any advice.
    hvacservicetech_07's Avatar
    hvacservicetech_07 Posts: 1,083, Reputation: 75
    Ultra Member
     
    #2

    Jun 16, 2007, 10:13 PM
    First you'll need a multi stage thermostat. Second, you need to run an 8 count between the thermostat and furnace, and 4 wires between the A/C and furnace. You'll need the following wires hooked up at the stat... R-24 volts, G-fan,W1- first stage heat,W2- second stage heat, Y1- first stage cool, Y2-second stage cool, C-common, It doesn't matter what colors you use, just be sure to mark everything and hook it all up the same, R- all the "R"'s will go together on the terminal strip on the furnace and so will the common's , hook your W1 and W2's on the terminal strip on the furnace. Now for the A/C wires... R- will go to the terminal on the furnace, and common will tie in with the common on the furnace, Y1 and Y2 need to be hooked with the Y1 and Y2 from the stat... Make sense? If not I can try to explaine this in a little more detail.

Not your question? Ask your question View similar questions

 

Question Tools Search this Question
Search this Question:

Advanced Search

Add your answer here.


Check out some similar questions!

2 Thermostats on one furnace [ 6 Answers ]

I would like to add a downstairs thermostat on my furnace. Will it hurt my electronic/programmable thermostat upstairs to simply wire another thermostat to the furnace? I understand the voltage would be sent back to it but it wouldn't go anywhere that it doesn't already when the upstairs...

Two thermostats controlling one furnace [ 1 Answers ]

I have a situation where I would like to have two thermostats controlling the furnace. There is no cooling system involved, just heating. Does this require any special type of controller? Or is it possible to just hook the two thermostats in parallel to the furnace?

Two thermostats to one [ 3 Answers ]

Right now I have two separate thermostats, one obviously controlling the A/C (heat pump), and the other controlling a gas furnace. To save money, I've upgraded the heat thermostat to a programmable thermostat (using two wires, red and green). I would love to have one thermostat controlling the...

Two Thermostats to One [ 2 Answers ]

I currently have a separate thermostat for the heater and the A/C... I want to combine them into one thermostat... I have replaced the thermostat before, but my knowledge of the wiring is very basic... My issue is that I have two "R" wires and I am worried about combining them together since it is...


View more questions Search