Wiring to old box - Electrical Supplies

You could do that but it would not be up to the electrical code requirements. Take the old one out and remove the wire nuts and put the new one in. There should be a ground wire stuffed in the box somewhere. Unless the house is really old. You connect the ground wire to the bare ones in the box.

This is the GPO junction using both BT (left) and old GPO (right). How far back are you going ? This setup assumes you have the British Telecom wiring at some point. Hope this helps...

Shooting from the hip here, but look at both the new and old wiring diagrams. Chances are that the new unit has terminal leads that would connect to the old units' relay/control box and you simply need to install the old box on the new A/C by connecting to the correct terminals. beyond that, you can build your own relay setup if you understand wiring diagrams. If you don't know wiring, I'd recomend taking to an RV shop, as you can damage either the A/C or the furnace or both if wired incorrectly... Hope this helped!

The green wire is the ground, just like the bare wire. Attach black to black, white to white, and green to bare.

Disconnect the green wire from the black wires. The green should only be connected to either a green wire in the box or to the box itself.
Gary

Hi,

Here is a tip that explains the wiring and the color designations...

Thermostat Wiring and Terminal Designations

Thermostat Problems - How to Change the Thermostat for Heating or Cooling

heatman101

Receptacle needs 1 Hot wire and 1 Neutral wire to complete circuit.
It sounds like you have 1 Hot wire and 1 Load wire but no Neutral wire.

Neutrals are not always present in switch box.
As a general rule, if a switch box has Neutral wires, they are twisted together and covered with wire nut, and then pushed to back of box.

Every receptacle box has Hot and Neutral wire. Hot connects to brass screw, and Neutral connects to silver screw. The two wires together complete circuit when you plug in a lamp.

So each receptacle box has Neutral wires, and you can get a Neutral wire from receptacle box and bring it over to the switch box. This work takes every tool and probably touch-up paint.

Here is a link showing how to drop a wire down to your switch box:
You have to tear out old switch box, and then install 'old work box.'
Old switch box is nailed into 2x4s. Pry box out a bit, then reach in with hacksaw blade and cut nails.
http://waterheatertimer.org/Install-owb.html

Here are two more links that show basic 240V and 120V circuits:
http://waterheatertimer.org/B220C.html
http://waterheatertimer.org/See-inside-main-breaker-box.html

Add a comment for more free help.
Also take advantage of fixyas phone service.
For a price, fixya expert speaks with you over phone while you work on electric.

Review old switches:
Two old switches > each has 2 wires
Old switch 1 > Red and White
Old switch 2 > Black and White
The same white wire connects to both switches, so effectively they count as 1 wire
This means you have 3 wires ... 1 White, 1 Red, 1 Black
Each switch controls a separate load (light, fan, motor)

New Leviton double-rocker switch:
-Leviton has 2 Brass-colored screws on one side, and these screws are connected together by a brass plate >> your Hot wire will connect to brass screw
-Leviton has 2 Silver-colored screws on other side, and neither of these screws are connected in any way >> the wires going to each load will connect on a different screw on this side of switch.

Hot wire: Each box in your house has exactly 1 hot wire that is connected back to breaker box. This is true for all boxes (excluding boxes that have a 3-way & 4-way switches).
We need to identify Hot wire.

-By code the Hot wire is black for identification purposes ... but your box sounds like maybe the Hot wire is White.
-If your Hot wire is white, that is NOT an immediate safety issue ... it will not cause a fire or malfunction ... it is a code violation ... because code requires things be uniform so next electrician knows what previous guy did. So some day, electrician working outside grabs wrong color wire, and wow. I say this so you know.

Moving on.

Identify Hot wire:
-Pull 3 wires up so they can be tested
-Turn on power
-Use ordinary tester, or old lamp with plug cut off and wires stripped back
-Tape tester lead to sticks so hands are away from voltage
-Power is on. Don't stand in water or touch metal pipes, and you're fine.
-You have 3 wires in box + ground wire
-Test all 3 wires to bare ground wire >> when tester lights up, that is Hot wire ... testing is complete

Connect wires to Leviton double-rocker:
-Power is OFF.
-You have 3 wires - 1 White, 1 Black, 1 Red >> one is Hot wire, the other two wires go to load
-Hot wire connects to Brass-colored screws on new Leviton.
-Brass colored screws are connected together by a brass plate so the Hot does not need to connect to both brass screws.
-The other two wires connect to Silver screws on other side of new Leviton switch
-One wire goes to each silver screw
-Connect bare ground wire to green screw.
-Push wires back into box. Use eraser end of pencil if needed.
-Make sure ground wire is back and away from screws on switch
-That's it.

I think you are saying a nail was driven into your wall and has gone through your thermostat wires? If that's the case here is a simple solution. Go to your local building supply such as Home Depot. Buy a an "old work" box which is designed to go into your wall where there is no stud. It will require you to cut a rectangular hole just large enough for the box, then tighten the screws to install... but dont do that yet. Get the box and a white or beige plain cover to fit it. The plain cover should have no holes except for the two screws to afix it onto the old work box. Cut a small hole next to where the nail went into the wires. Remove the nail and pull the wires out slightly. See which side has more slack. Locate the old work box on the side where the wires are shorter or tighter (less slack) and pull the other wire into the box so that both can be spliced together. If necessary finish cutting the wires the nail didn't sever. Do not cut red with any other wire at the same time because red is the power (24 vac hot) going to the thermostat. When you have pulled both wires into the old work box and tied a knot to prevent them slipping out, then fit the box into the wall hole and tighten the screws to draw the box snug to the wall surface. Splice each color with a wire nut, tiny wire nuts that are blue or grey are for 18-24 gauge bell and thermostat wires. Join red to red, white to white, yellow to yellow, blue to blue, orange to orange, green to green, etc until all are finished. Doing this will eliminate the need to research which wires are actually in use for your application. Install the cover plate. Test your repair.

Review this Wiring Schematic about Olds 98 ('89, '90 & '91):
1989 1
1989 2

1990 1
1990 2

1991 1
1991 2

I really hope help you with this (remember rated this help). Good luck.