To identify the thermostat wires, you should:
- Turn the thermostat and the HVAC unit off.
- Locate the HVAC control board – this is where the thermostat wires connect to the heating and cooling system.
- The wires will most likely be color-coded. They should also be labeled.
How to wire your line voltage thermostat?
When to Call a Professional
- Attach a Wire Nut to Ground and White Wires. ...
- Wire-Nut One Hot Wire to Bypass the Thermostat. ...
- Attach the Line and Load Black Wire to Thermostat. ...
- Push the Green, White, and Red Wires Into the Box. ...
- Line up the Screws on the Box. ...
- Screw the Thermostat Into the Box. ...
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.
How to connect thermostat wiring?
Steps Download Article
- Read the manufacturer's instructions. Before wiring a new thermostat into your wall, review all tips, suggestions and pictures provided in the instructions.
- Turn the electricity off to the thermostat. Flip the switches at the breaker box that corresponds to your furnace and air conditioner.
- Take down the old thermostat and wall plate. ...
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.
What color wire goes where on a thermostat?
This is the most typical thermostat wiring style, and it applies to systems that regulate both heat and air conditioning. The wires are typically arranged as follows: red for 24-volt hot, white for heat, yellow for cooling, green for the fan, and blue for common (although the common wire may be a different color).
What are the 5 thermostat wires?
5 Wire Thermostat Wiring (Any HVAC Device – Air Conditioners, Heat Pumps, Furnaces, etc.)Red wire for power (24V).White wire for heating (connected to W or W1 terminal).Green wire for fans.Blue or yellow wire for cooling (connected to Y).Black wire for “C” or “Common” wire.
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.
What color is the C wire?
Blue wiresBlue wires are also called “C” wires because they are the Common wire. C wires are necessary for any “smart” thermostat that needs to be connected to a power source 24/7, regardless of your heat pump type.
Is RC and C wire the same?
The C and Rc wires are not the same. To install this thermostat you should follow the exact same wiring of the previous thermostat.
Does red wire go to RC or RH?
There is no standard for the colour of the RH wire, but most units use a red one. The RC wire, on the other hand, refers to “red cooling”. It's the same with the RH wire in that it powers the thermostat. For the RC, it powers the cooling system.
What are some of the common mistakes when installing a thermostat?
4 Mistakes You May Be Making With Your ThermostatNot Using a Programmable Thermostat. ... Not Programming the Thermostat Properly. ... Bumping the Temperature Up/Down to Quickly Heat/Cool Home. ... Not Maintaining the Thermostat.
Can you touch thermostat wires?
It's "ok" in that if it works, you're probably in the clear. However, there is a high risk of letting some of the thermostat wires in the bundle touch while doing this (the wrong ones) which would cause a short/surge back to the controller board.
Why is there a jumper between R and RC?
In most cases, the heating and cooling system share a single transformer by leaving the jumper in the lower right corner it connects the RC and RH to power heat and cool features.
How do I know if C wire is live?
0:110:48Use a Multi Meter to Test for a "C" Wire - YouTubeYouTubeStart of suggested clipEnd of suggested clipBegin by putting one probe whichever probe you want on the rh wire and test every other wire withMoreBegin by putting one probe whichever probe you want on the rh wire and test every other wire with the other probe. One of the wires will show up is 24 volts and that is your c wire.
Does C wire have voltage?
What Is a C Wire? The C wire, a.k.a. the "common wire", allows a constant flow of 24 VAC (volts AC) power to a smart thermostat. However, the C wire doesn't provide the actual source of power to the thermostat. The wires that provide the source of power are the R wires (or hot wires).
Which one is the C wire on a thermostat?
When you open your thermostat, you can quickly identify your C-wire among five coloured wires by locating the wire (usually blue) connected to 'terminal C. ' You may find there are fewer than five wires, or there is no wire attached to terminal C. It's possible that the wires are tucked inside the wall.
How do you wire a 5 wire Honeywell thermostat?
1:5713:06How to install a thermostat 5 wire Honeywell - YouTubeYouTubeStart of suggested clipEnd of suggested clipRight you use the top lines. If you have a heat pump use the bottom you see the see is optional withMoreRight you use the top lines. If you have a heat pump use the bottom you see the see is optional with batteries that you're commonly it's like a ground.
What wire controls heat on thermostat?
white wireThermostat Wiring Tips 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.
Is B the same as C on thermostat?
The common wire, usually labeled C, should go in the C Terminal of the Zen Thermostat. A wire labeled O, B, or O/B is used to control whether a heat pump is in heating or cooling mode. However, on some thermostats, a wire labeled B is the common wire C. In most cases, the common wire is labeled C.
What does the black thermostat wire go to?
This the Common Terminal, and usually, a blue or black wire is run to the transformer from this terminal to complete the circuit, and in some cases, provide power to the Thermostat. This terminal is found on thermostats designed to work with Heating Pumps and is used to power the defrost cycle on the heat pumps.
What is the yellow wire on my thermostat?
Yellow Wires. The yellow wires underneath your thermostat connect to your compressor. They control your air conditioning system. The yellow wires terminate at your compressor contactor via an air handler. The yellow wires connect to the Y terminals on your thermostat.
Where is the green wire on a thermostat?
The green wire underneath your thermostat connects to the fan of your furnace or air handler. It terminates at the air handler or furnace. The green wire connects to terminal G on your thermostat.
What color wires are used for a heat pump?
This thermostat wire color code will help homeowners understand the anatomy of their thermostat: 1 White wires 2 Yellow wires 3 Green wires 4 Orange wires 5 Red or “Rc” wires: Industry standard for geothermal heat pumps 6 Rh wires: Industry standard for geothermal heat pumps 7 Blue or “C” wires
Why are blue wires called C wires?
Blue wires are also called “C” wires because they are the Common wire. C wires are necessary for any “smart” thermostat that needs to be connected to a power source 24/7, regardless of your heat pump type.
What is the red wire on a transformer?
The Rh wire, another type of red wire, is also responsible for 24-hour volt power from your transformer. The Rh wire connects to your heating system as opposed to your cooling system. This wire may be red without an “H” attached to it, depending on if you have a dual transformer setup.
What are the different types of wires on a geothermal heat pump?
Yellow wires. Green wires. Orange wires. Red or “Rc” wires: Industry standard for geothermal heat pumps. Rh wires: Industry standard for geothermal heat pumps. Blue or “C” wires. Make sure you know what’s happening underneath your thermostat! Read on for information about all possible thermostat wires.
What does a red wire mean?
Red wires indicate power. You may see an Rc and/or an Rh wire.
Overview
- You’ll need to check your current thermostat’s wires to tell if your system is Nest thermostat co…
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 colo…
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 sys…
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 may …
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 usuall…
• 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 c… - • 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 actua…
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.