Yellow Thermostat Wire (“Y1” And “Y2” Wire) Y terminals are for the connection to the compressor relay. It most often wires to the air handler (indoor split-system unit). Y1 is for ordinary or one-stage cooling; this is what most of us have at home. Y wire with “Y1” code is usually yellow-colored.
How to wire your thermostat?
How to wire and secure your new programmable thermostat. Step 1: Wrap each wire underneath the appropriate screw, according to your notes or labels. Step 2: Use a screwdriver to tighten each screw around each wire. Step 3: Before securing the thermostat unit to the mounted base, be sure new batteries are put in and the reset button is pushed to ...
What is the green wire on a thermostat?
So, this is what you might expect to see in terms of colored wires and what they mean:
- White – The white wire is what connects to the (auxiliary) heat on your system.
- Yellow – The yellow wire connects to your compressor.
- Green – The green wire connects to the fan.
- Orange – This wire connects to your heat pump (if you have one).
- Red – Now, there can be two separate wires for this. ...
- Blue – This is your common or “C” wire.
Does my thermostat have a "C" wire?
Usually “C wire” or the Common Wire will be a blue coloured wire. But there is no particular standard for thermostat wires, so it can be any color like Yellow, Brown, Green or any other color. If you see a wire of different color, say Yellow in the ‘C’ terminal of your current thermostat, most probably it should be your ‘C’ wire.
What is the RC wire on a thermostat?
“RC” and “RH” are terminals on an HVAC thermostat, each with a specific function. They are used with HVAC systems with two separate transformers – one for cooling and one for heating. The RC terminal supplies the 24-volt cooling power, and the RH terminal is the 24-volt heating power supply.
How do I fix Nest error Y1?
The Y1 wire is actually just for cooling. It appears that error code often indicates too much voltage on the wire. This could be a problem with the HVAC system rather than the thermostat. If this is a new Nest installation verify the wiring to ensure it is correct.
What does no power to Y1 wire mean?
Second: No power to Y1 is an indication of a problem with the AC. Sometimes condensate overflow or low on refrigerant. To check disconnect wires from the Nest base. Then twist together the Rh, G, and Y1. This should turn on the AC and fan.
What is Y1 and Y2 wire on thermostat?
Y/Y1 and Y2. In conventional cooling systems, Y/Y1 controls the first stage of cooling and Y2 controls the second stage, which helps cool down the home faster. In heat pump systems, Y1 controls your compressor, which heats and cools your home.
Do I need the Y2 wire on a thermostat?
Y2 is the thermostat wire for second stage of cooling. Y wire is for the first compressor (air conditioner units) and Y2 wire is for the second compressors (air conditioner unit). Y2 wires apply only if you have two air conditioner compressor units running from one AC thermostat.
What causes no power to thermostat?
A quick fix to restore your thermostat's power is a tripped circuit breaker or blown fuse, depending what you have in your home. Sometimes a surge can cause this issue. If you check your electrical box and a circuit breaker is tripped, just flip it back. If you have fuses, replace the fuse.
What happens to Nest thermostat when power goes out?
If backup power runs out, you'll get a notification that Nest Secure is about to shut down. Before it shuts down, Guard will disarm. Its status will also change to Offline in the Nest app.
What happens if you wire a thermostat wrong?
Potential consequences of improper installation could include: Electric shock. Blowing a circuit breaker. Damaging the thermostat unit, the electrical system or even the AC/furnace unit itself.
Is Y1 the same as Y thermostat?
The W or W1 wire controls your heating system. In most systems, the Y or Y1 wire controls your cooling system. If you have a heat pump, your Y or Y1 wire controls your compressor. Your compressor is responsible for heating and cooling your home.
What color is the Y wire on a thermostat?
yellowThermostat Wiring Tips The W wire is connected to your heating system. If your thermostat controls your heat, you will have a white wire. The Y wire is yellow and connects to your air conditioning compressor. The G wire is green and connects to the fan.
Does Y wire go to Y1 or Y2?
Of the Y, Y1, and Y2 wires, Y or Y1 go to the Y terminal and Y2 to the Y2 terminal. The O/B wire can have many configurations. It can be W-O/B, O/B, W-O, W-B, or even separate O and B wires. If you have separate O and B wires, tape off the B wire so it doesn't make contact and connect the O wire to the O/B terminal.
What's the difference between Y1 and Y2?
In standard systems, Y/Y1 controls the first stage of cooling, and Y2 controls the second stage.
Where does the Y2 wire go on a Nest thermostat?
Correct, you have single-stage heating with two stages of cooling and the */OB terminal is where the Y2 would go. Correct, you have single-stage heating with two stages of cooling and the */OB terminal is where the Y2 would go.
How do you trace a wire that has no power?
How to Trace a Wire with No PowerUsing the Circuit Breaker. If each circuit breaker is properly labeled, you can quickly determine the area or device that it connects to. ... Stud Finder. Vertical electrical wires usually run along wall studs. ... Voltage Detector. ... Tone Generator.
What can you do with low voltage wiring?
Low voltage wiring is often used for Smart doorbells, telephones, garage door opener controls, heating and cooling thermostats, landscape lighting, alarm system sensors and controls (security system cameras, motion sensors), audio-visual wiring (surround sound audio systems, cable television, intercom systems), ...
Can you use thermostat wire for LED lights?
Even if the supply is listed as Class 2 using small gauge wire such as thermostat wire is a bad idea. The voltage drop is going to greatly effect the lighting performance. There is 10 times as much current on a 12 volt lighting system as there is for the same system operating at 120 volts.
Is low voltage wiring required to be in conduit?
Low-voltage (no more than 30 volts) wiring must be buried at least 6 inches deep. Buried wiring runs that transition from underground to above ground must be protected in conduit from the required cover depth or 18 inches to its termination point above ground, or at least 8 feet above grade.
How many wires does a Honeywell thermostat have?
With the basic Honeywell thermostat, you will find: 8 wire sockets to the left. 8 wire sockets to the right. Before we take the flathead screw to unscrew these, let’s first familiarize ourselves with the crucial part of any thermostat wiring: Wire codes and colors. Here’s where the thermostat wires go:
What wire does an air conditioner thermostat use?
All air conditioner thermostats have a red wire for power. You may also have Rc or Rh terminals for dual transformer systems; these are special cases in thermostat wiring.
What is the red wire on an air conditioner?
Thermostat Red Wire (“R” or “Rc” Wire) Red wire or “R” wire is the power wire. They originate in the transformer (air conditioners; in the air handler) and provide the 24-hour volt AC power. All air conditioner thermostats have a red wire for power.
What is the black wire on a thermostat?
The black wire or blue wire (either color is used) is the C – “Common” wire. What does the C wire do? C wire is connected to the transformer and completes the 24V electric circuit. Newer thermostats have a continuously looped 24V circuit; in older models, the loop is completed only when the power is required (when you turn the AC on, for example).
What is a thermostat?
Thermostats are the ultimate control hubs for HVAC devices such as furnaces and air conditioners. Thermostat wiring is a useful skill to know if you have to replace an old thermostat or just check if something is wrong with the new thermostat. With a little help, you can learn how to install a thermostat on your own.
How many sockets does a thermostat have?
As you can see on the thermostat base, you have 16 sockets, with letters C, R, W1, W2, O/B, G, Y1, Y2, BK, 2x RS, 2x ODT, AUX NO, AUX C, and AUX NC. With 2 wire, 3 wire, and 4 wire thermostats you don’t have all of these. That’s normal. You might also notice that all sockets don’t wire in them. That’s standard as well.
What is the difference between a 2 wire and a 3 wire thermometer?
The difference between 2 wire and 3 wire thermometer is the “G” or green wire that is usually used for fans. In the 3 wire thermostat wiring, the green wire serves as a repurposed C or “Common” wire. Here are the 3 wires: Red wire for power (24V). White wire for heating (connected to W or W1 terminal).
What is the C wire on an Ecobee thermostat?
Also known as the common wire, the C wire enables the continuous flow of 24VAC power that ecobee thermostats need to operate.
What do all the thermostat terminal letters/wiring labels mean?
Use the Thermostat Compatibility Checker to see if an ecobee thermostat will work with your system.
How many R wires are in a dual transformer?
With dual-transformer systems you’ll have two R wires—one from the cooling transformer (Rc) and one from the heating transformer (Rh). Learn how to install an ecobee thermostat in a dual-transformer system.
What wires are used for ecobee heat pump?
If you have a heat pump system with auxiliary heating, you will normally connect the wire labelled AUX/AUX1 or W2 to the ecobee’s W1 terminal. If you have two stages of AUX heat, connect the AUX2 wire to the ecobee’s W2 terminal.
What wires tell the compressor when to switch between heating and cooling?
On heat pump systems, the O and B wires tell the compressor when to switch between heating and cooling your home.
What controls the fan speed in HVAC?
Most HVAC systems feature a single fan speed. In multi-speed systems, fan speed is either controlled by the furnace control board or the thermostat.
What is an auxiliary heat pump?
Heat pumps systems sometimes have a second, auxiliary heat source that helps warm your home quicker and keeps the home warm in frigid weather conditions when the heat pump cannot. Some auxiliary heat systems for heat pumps have two stages, hence AUX2.
What is Y1 in heat pump?
Y1: The Y1 terminal is used for the compressor contact in a single-stage heat pump installation.
How many wires do you need for a thermostat?
Some new thermostats require no more than two wires and will work fine if the extra wires are left unattached. Your thermostat may also have extra terminals that don't apply to your particular HVAC system; again, it is not a problem if not all the terminal connections are used.
What is a Y/O terminal?
Y/O: The Y/O terminal is used to control the cooling condenser. When the thermostat calls for cooling, signals are sent to power up the condenser and the blower fan, cooling your home.
What is a thermostat?
A thermostat is wired to a furnace or air conditioner unit and acts as a switch to turn the unit on and off automatically , based on the thermostat's temperature setting and/or programmed time schedule.
What is the G terminal on a fan?
G: The G terminal controls the fan relay and is responsible for turning the blower fan on and off automatically or manually via the thermostat.
Can you use a transformer to wire a thermostat?
Most thermostat wires operate on 24-volt power provided by a transformer, and they are generally safe to work on without shutting off the circuit feeding the thermostat wiring. However, if the low voltage wires touch each other during the work, the system's internal fuse will blow.
Is a thermostat a low voltage device?
The thermostat that is used to control the heating and cooling (HVAC) system in your home is a low-voltage device that is easy enough to replace. And replacing one is a very common project, as homeowners swap out older thermostats requiring manual adjustment with newer programmable thermostats that change temperatures automatically at preset times.
Why is the common wire used in Nest thermostats?
Because the common wire is used to provide consistent power to the thermostat, it’s important to determine what function a wire labeled B serves before connect ing it to a Nest thermostat.
What happens if you put wires in the wrong thermostat?
If you put wires into the wrong thermostat connectors during setup can, this can cause your system to malfunction or possibly damage it.
How to tell if a B wire is a common wire?
How to tell if a B wire is really a common or C wire. Wires labeled B typically should go into a Nest thermostat's O/B connector. But for some systems the wire in the thermostat 's B connector is actually a common or C wire. Common wires should go in your Nest thermostat's C connector.
How to check if Nest thermostat is compatible?
Usually, you just remove your thermostat’s cover and enter the wires you find into the compatibility checker. The Nest app and Home app will also let you know if your system is compatible and give you a wiring diagram for installation.
What does orange wire mean on a heat pump?
If the wire in the O/B-W connector is orange: you probably have a heat pump. (Check the picture above.)
What is a jumper wire?
Jumper wires connect two thermostat terminals together (often Rc and Rh), but they aren’t “two label” wires. Jumpers aren’t connected to the system and don’t run back into the wall.
How to tell what an unknown wire is?
Checking your system's control board is a very reliable method for determining what an unknown wire is. The control board’s connectors typically have labels that can tell you what each wire is when other methods aren’t convenient or don’t work.
What wire does an air conditioner thermostat use?from learnmetrics.com
All air conditioner thermostats have a red wire for power. You may also have Rc or Rh terminals for dual transformer systems; these are special cases in thermostat wiring.
What is a 5 wire thermostat?from learnmetrics.com
5 wire thermostat is basically a 4 wire thermostat with a “C” or “Common” wire. The newer digital thermostats for HVAC devices all require a 24V C wire connection to function. 5 wire thermostats are the most versatile thermostat; they control anything from smart air conditioners, heat pumps, furnaces, and so on.
What color wires are used in a Nest thermostat?from learnmetrics.com
In addition to heating (2 wire thermostats) and C or fan (3 wire thermostats), 4 wire thermostats include the cooling wire, usually in blue or yellow color.
What is a thermostat?from thespruce.com
Thermostats are the ultimate control hubs for HVAC devices such as furnaces and air conditioners. Thermostat wiring is a useful skill to know if you have to replace an old thermostat or just check if something is wrong with the new thermostat. With a little help, you can learn how to install a thermostat on your own.
How to remove Honeywell control panel?from learnmetrics.com
Most control panels can be removed just by nudging it from below or above a bit. Some Honeywell thermostats can have some screws as well; just unscrew them to expose the wire terminals.
What is the difference between a 2 wire and a 3 wire thermometer?from learnmetrics.com
The difference between 2 wire and 3 wire thermometer is the “G” or green wire that is usually used for fans. In the 3 wire thermostat wiring, the green wire serves as a repurposed C or “Common” wire. Here are the 3 wires: Red wire for power (24V). White wire for heating (connected to W or W1 terminal).
What color is the cooling wire on a 4 wire thermostat?from learnmetrics.com
In addition to heating (2 wire thermostats) and C or fan (3 wire thermostats), 4 wire thermostats include the cooling wire, usually in blue or yellow color. Here are the wires in 4 wire thermostats with terminal codes and color codes:
Where does the red wire come from on a thermostat?
The red wire should always come from the hot side of the 24-volt transformer. Additionally, the common (sometimes black) should come from the common side of the transformer.
Where are thermostat wires terminated?
Remember, the wires coming from the thermostat are terminated in the HVAC equipment . Importantly, there is a high voltage inside the air handler, boiler, or other equipment where the wires terminate. Some HVAC system manufacturers provide a terminal strip board where the wiring is attached.
What does C stand for in thermostat?
C stands for common, and there is no universal color used for this terminal, although black is the most common color I’ve seen. For the thermostat, wiring colors code for this terminal (if equipped) consult with the installer. Finally, if that is not possible, then trace the wire out to the source.
Where is the R terminal on a split system?
R – The R terminal is the power. It is a red wire and comes from the transformer usually located in the air handler for split systems, but you may find the transformer in the condensing unit. For this reason, kill the power at the condenser and the air handler before changing or working on the wiring at the t-stat. Lastly, if you have a package unit, then the transformer is in the package unit.
What is the terminal for a heat pump?
O or B – These terminals are for heat pumps and the B t-stat terminal is used on for Rheem or Ruud and any manufacturer that energizes the reversing valve in heating mode for the heat pump. Furthermore, other manufacturers of heat pumps utilize the reversing valve for cooling. The O thermostat terminal is for this purpose. This wire goes to the outside heat pump condenser, for reversing valve control. Finally, this is for heat pump thermostats.
What terminal is used for second stage cooling?
Finally, many systems only have a single compressor but if you have two compressors (or a two stage compressor) which should only operate off of one thermostat then you need the Y2 thermostat terminal for second stage cooling.
What wire do you use for a reversing valve on a Trane?
If you have a Trane, Carrier, Goodman, Lennox, Ducane, Heil, Fedders, Amana, Janitrol, or any other manufacturer other than Rheem or Ruud, you will be utilizing the orange wire for reversing valve. Lastly, Rheem and Ruud will usually use the blue wire for the reversing valve.
What is Y1 wire?from doityourself.com
Y1 is the wire that goes to the outside A/C condenser.
What is the yellow wire with a red stripe on the thermostat?from justanswer.com
OK so the yellow wire with a red stripe is your high pressure switch and the blue wire with a red stripe is the low pressure switch. The way this system works is the 24V call comes through the thermostat wire and links to the Yellow wire with a red stripe. The 24V travels though that wire past the high pressure switch and then on to the blue wire with red stripe loop and then goes through the low pressure switch and back to the contactor. If both switches are closed your contactor turns on.
Why is my thermostat yellow and white?from justanswer.com
you switched yellow and white? Same AC error? Check your thermostat wire outside by the condenser (outdoor unit). Sometimes a mouse can chew up wires or dogs can dig near them. Make sure you don’t have damaged wiring that is causing a short or a no call situation.
How to check if Nest thermostat is compatible?from support.google.com
Usually, you just remove your thermostat’s cover and enter the wires you find into the compatibility checker. The Nest app and Home app will also let you know if your system is compatible and give you a wiring diagram for installation.
How to eliminate a loop in a thermostat?from justanswer.com
2. You can eliminate a loop by disconnecting the yellow/red wire and connecting the thermostat wire to the blue/red wire direct. If that does not blow the fuse the short is in your yellow/red. If it still blows the fuse then its in your blue/red loop.
Why is the common wire used in Nest thermostats?from support.google.com
Because the common wire is used to provide consistent power to the thermostat, it’s important to determine what function a wire labeled B serves before connect ing it to a Nest thermostat.
What is a jumper wire?from support.google.com
Jumper wires connect two thermostat terminals together (often Rc and Rh), but they aren’t “two label” wires. Jumpers aren’t connected to the system and don’t run back into the wall.
What is the yellow wire with a red stripe on the thermostat?
OK so the yellow wire with a red stripe is your high pressure switch and the blue wire with a red stripe is the low pressure switch. The way this system works is the 24V call comes through the thermostat wire and links to the Yellow wire with a red stripe. The 24V travels though that wire past the high pressure switch and then on to the blue wire with red stripe loop and then goes through the low pressure switch and back to the contactor. If both switches are closed your contactor turns on.
How to check thermostat wire?
Check your thermostat wire outside by the condenser (outdoor unit). Sometimes a mouse can chew up wires or dogs can dig near them. Make sure you don’t have damaged wiring that is causing a short or a no call situation. Ask Your Own HVAC Question.
How to eliminate a loop in a thermostat?
2. You can eliminate a loop by disconnecting the yellow/red wire and connecting the thermostat wire to the blue/red wire direct. If that does not blow the fuse the short is in your yellow/red. If it still blows the fuse then its in your blue/red loop.
How to test if a wire is broken?
If you’re getting an error most likely reason is the wire is broken somewhere.The best way to test for a broken wire is to get a multimeter with continuity reading. That means when its two leads touch a conducting surface it beeps. Then what you do is first turn off the power.
What to do if Y1 wire is broken?
You might have a broken Y1 wire I suggest turning off power and picking a different color wiring. Switch it at the Nest thermostat and at the furnace or air handler.If this resolved the issue please rate your experience. It’s the only way I can close out the call. If you need further assistance let me know.
Does AC blow when connected to contactor?
AC. And it only blows when its connected to the contactor. My original test (take a look at the picture attached) I disconnected the T-stat wires from the blue wire nuts, kept them separated and tested their continuity.
Does a contactor coil blow a fuse?
Per your description that the fuse only blows when the contactor is connected, the short is in your condenser. I have never seen a contactor coil short but it is possible. I would be 99% the short is a wire rubbed raw. Take several pics of the condenser with the top off and the control panel area. Let me see what you got.
What is Y1 wire?
Y1 is the wire that goes to the outside A/C condenser.
Why is Y1 disconnected?
Y1 can be disconnected due to a safety switch. One safety is in the outside unit that is triggered when it senses low pressure/temperature. Another safety switch is usually attached to the furnace/air handler's condensate overflow switch.
How does a 24VAC nest work?
Refer to the diagram. The 24vAC comes into the nest on R. R connects to the internal battery. The battery needs a connection to C so by being inline it gets it's C from the air handler thru the contactor, thru the low pressure switch and to the Y1 connection. So as long as there is a wire in the Y1 terminal..... the charge is handled thru the Y1 line. If you have a low charge the pressure switch will open the Y1 circuit.
What does Y1 loss mean?
A Y1 loss means a break in the wiring somewhere from the stat to the contactor in the outside condenser.
When you add a direct C connection to the nest, does it need to steal power?
When you add a direct C connection to the nest it no longer needs to steal power.
Can I swap thermostats from upstairs to downstairs?
I also completely swapped thermostats from the upstairs unit to downstairs unit. Before I only swapped the faces. The upstairs unit did the same thing when I installed it and the downstairs unit worked fine upstairs, so the thermostat isn't broken.
Overview
- You’ll need to check your current thermostat’s wires to tell if your system is Nest thermostat com…
Usually, you just remove your thermostat’s cover and enter the wires you find into the compatibility checker. The Nest app and Home app will also let you know if your system is compatible and give you a wiring diagram for installation. - Sometimes a thermostat’s wire connectors have two labels, which can be confusing, or no label …
There are several ways to identify your thermostat wires:
1. Turn off the main power to your system at the breaker box
- Before you turn off the power, make sure each wire coming to your thermostat is a different color…
Your system can have multiple breakers, so make sure to turn them all off before moving on. Once the power to your whole system is off, check your furnace and fan. Make sure there are no lights that might indicate your system still has power.
2. Test that power is off
- Try to turn on your system. If you have both heating and cooling, try to activate both as each co…
1. Turn the temperature up on your thermostat at least 5 degrees to try to turn on your furnace. - 2. Wait at least 5 minutes to check if your system turns on (you’ll need to wait because many sy…
3. Turn the temperature down on your thermostat at least 5 degrees to try to turn on your AC.
3. Remove your system's panel
- Once you’re sure you’ve turned off the power, look for a removable panel on your system. It ma…
To learn more about removing your system’s panel, consult the user guide for your HVAC system or contact a local pro in your area.
4. Look for the wire connectors
- When you’ve removed the panel, look for the control board. It looks like a circuit board and usual…
• If you need help finding your HVAC system’s control board, consult the user guide for your HVAC system or contact a local pro in your area. - Look for connectors that have labels that are the same as your thermostat. For instance, you mi…
Look at the labels where these wires connect to the control board to determine what each wire attached to your thermostat should be labeled.
5. Take a picture of the wire connectors
- Take a picture of the wires and connectors on your system’s control board. Make sure the connector labels are clearly visible.
6. Close your system's panel
- Some systems have a safety feature that will keep them from turning on unless the panel is fully closed. If your system doesn’t turn on after you’ve turned the power back on, double check that the panel is shut properly and that any latches are secured.
7. Use the Nest or Home app to get a wiring diagram
- The in-box instructions will let you know which app to use for setup: the Nest app or Google Home app. When you begin setup with the app, you’ll get a custom wiring diagram. Now that you have a picture of the wires connected to the control board, you can use it as a reference to enter wires into the app and help make sure that your wiring diagram is accurate for installation.
More help with wire labels
- Thermostat wires with two labels
• Some thermostats have wire connectors with two sets of labels: one for conventional systems, one for systems with a heat pump. You need to know whether you have a heat pump or conventional system so you know which thermostat labels to enter into the Nest compatibility ch… - • If you put wires into the wrong thermostat connectors during setup can, this can cause your sy…
Important: The side that the wires come out of the connectors doesn’t matter. In the picture above, you might assume that this thermostat is connected to a conventional system because the wires are coming out of the conventional side of the connectors. In fact, this thermostat is actually con…
What thermostat wire labels mean
- Below are some of the wire labels you might find on your thermostat and what they do.
The app will give you a custom wiring diagram to help you install the Nest thermostat. Refer to the following article for step-by-step installation instructions. - How to install your Nest thermostat
Note: If you don’t find your wiring labels in this article, contact a local pro.