? asked in Home & GardenMaintenance & Repairs · 1 decade ago

How do I install new programmable 5 wire thermostat?

I have a new digital programmable hunter 44360 thermostat I am trying to install in a house with a 1986 ArcoAire gas furnace (no heat pump) and Trane A/C. The old thermostat has 5 wires:

white - W1

blue - B

yellow - Y1

red - R

green - G1

The new thermostat has the following:

RH - 24 volt

RC - 24 volt cool

G - fan

Y/O - a/c compressor

W/B - heating

Y1 - heat pump compressor

Everything I read about blue says that it's for a heat pump (which I don't have) or that on some trane systems, it's common. The thermostat says not to hook up a common wire, to tape it and leave it alone. But it was hooked up on the old thermostat.

So how should I wire this? I'm basically confused about the blue and the white wires, the rest seem self explanatory. The book refers to either the B (which it refers to as a reverse valve operating in heat mode for heat pumps) or the W going to the W/B. I'm pretty sure both don't go together.

Update:

Yes I have looked at the panel in the furnace. The blue wire is connected to "C" which I believe is common. I found a manual on arcoaire which said that blue was common when used but it was an electric furnace, not gas and not the same model as mine so I don't put too much faith in it.

8 Answers

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  • done
    Lv 4
    1 decade ago
    Favorite Answer

    I refer to this link when my memory fails me... which is often.

    http://www.toad.net/~jsmeenen/wiring.html

    What is really important is what the wires are connected to. No, I'm not poo-pooing color codes. Rather, emphasizing that you should be concerned with what the wires are doing as opposed to their color.

    So...

    Go to your furnace and open the compartment where the t-stat wire connects up. Note the colors of the wires actually connected to the furnace and what the terminal is labeled.

    These are the only connections/wires you should fret about.

    Ten-to-one it will be clear then.

    G'luck.

    ~+~+~+~+~+~+~~+

    On edit after Additional Details:

    Well, I would say the common would only be needed if the t-stat requires an outside power source to operate. The website says it is battery operated. No problem there.

    Really, for a single stage heat / single stage cooling system you are focusing on four connections.

    1) Red wire - the power - 24 A/C hot - (RH)

    2) White - heat call - (W/B)

    3) Yellow - A/C call - (Y/O)

    4) Green - Fan on - (G)

    Think of the t-stat as a switch. It closes to send voltage to a terminal which triggers the board (or relays) to spring into action.

    Clear as mud? ;)

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  • 5 years ago

    This Site Might Help You.

    RE:

    How do I install new programmable 5 wire thermostat?

    I have a new digital programmable hunter 44360 thermostat I am trying to install in a house with a 1986 ArcoAire gas furnace (no heat pump) and Trane A/C. The old thermostat has 5 wires:

    white - W1

    blue - B

    yellow - Y1

    red - R

    green - G1

    The new thermostat has the following:

    RH - 24...

    Source(s): install programmable 5 wire thermostat: https://tinyurl.im/fXkPs
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  • saleh
    Lv 4
    3 years ago

    5 Wire Thermostat

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  • Dean C
    Lv 6
    1 decade ago

    In my experience with simple heat systems ( gas furnace with AC) The wire colors should be

    White heat

    Red hot

    Yellow Cool (AC compressor)

    Green fan

    That is assuming that they were wired properly. You may have to do as Rancidcrab said and go out and trace every thing down.

    If there was another terminal it could be for aux heat or heat pump. You normally will not find a gas thermostat that will operate a heat pump, but a heat pump thermostat will operate a gas furnace as Aux heat.

    On the new thermostat RH and RC are for if you have a two transformer system, one will be where ever the air handler is and the other will be outside in the condenser unit. If it is a single transformer system, then your hot wire from the transformer (usually red) is attached to either the RH or RC and a jumper applied to the other.

    G green or what ever is on G1

    Y/O yellow or what ever is on Y1

    W/B white or whatever is on W1

    Hope this helps

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  • Anonymous
    1 decade ago

    First off, do NOT remove the jumper between RC and RH if the heat and ac are one unit. You only remove the jumper if you have two separate systems, example: baseboard heat and ac.

    Separate systems have two transformers and require the jumper to be removed so that the transformers do not buck one another.

    Removing the jumper and connecting the R wire to either the RC or RH terminal will mean that you will only have heat OR ac and not both.

    The blue wire that is connected to C or Common on your furnace is only used if you have a thermostat that can either be run by batteries or the 24volts that the furnace supplies.

    good luck

    Source(s): This is coming from my boyfriend whom is a certified HVAC technician.
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  • Janice
    Lv 4
    4 years ago

    For the best answers, search on this site https://shorturl.im/axY3C

    Chances are good that black is G, blue is never used for G. Most 5 wire stat wire would have all those colors except black would be green. The blue wire is probably the 24v common wire and is not needed on your new stat, just tape the end up with black tape and stuff it back in the hole in the wall. If the blue wire touches the red wire (copper to copper) it will either short out your control transformer or blow the low voltage fuse if there is one.

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  • Joe S
    Lv 5
    1 decade ago

    5- wire systems indicate 2- 24V transformers. 1 on the cond. outside and 1 for the funace. RH will go to the red wire. Rc will go to the blue wire G1 will go to green. Y1 will go to yellow. W1 goes to white or WB on your new stat. Don't put anything on Y1.

    Heat = white

    blue= RC

    Green = fan

    Red= RH

    Yellow=a/c compressor

    That should do it,

    • Correction, first he meant Y0 and nothing connected to Y1...

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  • DAN Y
    Lv 4
    1 decade ago

    White goes to W/B ...Blue to RC...Yellow to Y/O...Red to RH... Green to G

    If there is a jumper between RH andRC , remove it.

    You have to remove the jumper if you are powered by two sources, such as an oil primary control powering RH and a fan center (on the same furnace ) powering RC. See ...same unit different power sources.

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