What do the s and L wires do on an ecobee thermostat?
S terminals are for outdoor temperature sensors. ecobee thermostats obtain weather data over Wi-Fi so S wires aren’t necessary. The L wire can be used to power indicator lights on older thermostats. ecobee thermostats feature an LCD display so the L wire isn’t necessary. Most HVAC systems feature a single fan speed.
What are the wires on a 4 wire thermostat?
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: Red wire for power (24V). White wire for heating (connected to W or W1 terminal). Green wire for fans.
Where does the yellow wire go on a thermostat?
The yellow wires connect to the Y terminals on your 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 is the C wire on a thermostat?
There is no universal color for this wire terminal, but a black wire is often used. If your previous thermostat did not need this wire, the electrician would probably have rolled it around a wire or the wall terminal. In most modern 24V systems, the C wire is used to complete the power circuit for the thermostat if it consumes electricity.
What color wire goes to L on thermostat?
Thermostat Wiring Color Code ChartMarkingWire Color CodeDescriptionOOrangeChange-over relay to cool relayBBlueChange-over relay to heat relayAHeat and cool active to any relayLEmergency heat active lamp12 more rows
What is L1 and L2 in thermostat wiring?
For double-pole thermostats: Using wire connectors, connect a hot supply wire, which is typically black, to thermostat wire one (typically it is marked L1 or Line). Step 8. Connect the remaining supply wire, which is typically white, to the second thermostat wire (typically marked L2 or Line).
What does the Y wire do on a thermostat?
Y - This is the terminal for cooling or air conditioning and goes to the compressor relay. Typically a thermostat wire pull is made to the air handler on split systems and then this wire is spliced for the separate wire pull which is made to the condenser.
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 does L1 and L2 mean HVAC?
L1 and L2 represent the two poles on an AC power supply. L1 and L2 provide power to the components on the line side of the circuit. The control side of the circuit will not have lines for L1 and L2.
Is L1 load or supply?
A one way light switch has two terminals which is a common marked as COM or C. The common is for the live wire that supplies the input voltage to the switch. The other terminal is marked as L1 and is the output to the light fixture.
Does Y go to Y1 or 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 a jumper from R to RC?
If you have a wire in the R terminal, and another wire (not a jumper) in the RC terminal, you will not need to connect the R and RC terminals. See our Basic Wiring article for more info here.
Does C wire have voltage?
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).
Is RC the same as C wire?
The C and Rc wires are not the same. To install this thermostat you should follow the exact same wiring of the previous thermostat.
How do you wire a 5 wire Honeywell thermostat?
3:1113:06How to install a thermostat 5 wire Honeywell - YouTubeYouTubeStart of suggested clipEnd of suggested clipOne controls the cooling which is the C. And one controls the heat then you would take that jumpMoreOne controls the cooling which is the C. And one controls the heat then you would take that jump around okay modern systems splits heat pumps all that you only have one transformer.
What color wire goes where on a Honeywell thermostat?
W (white) controls the auxiliary heating elements. Y (yellow) controls the compressor on the cooling system. G (green) controls the fan. C (blue or black) provides a return path to the transformer.
What is L1 L2 on a furnace?
The word "circuit" is derived from the Latin, meaning "circle." L1 or L2, "hot" or "neutral" are merely words. Your typical outlet uses BOTH main connections, the slots, to power a device. The same current is moving through BOTH wires. On a 208 - 230 volt circuit used to power a condensing unit, same thing applies.
What is L1 and T1 on thermostat?
L is for line or supply. T is for load. Basically L is power in and T is power out. If you are trying to find which wire is coming from the panel, yes the power must be on. The one from the panel will show voltage.
What is L1 electrical?
The incoming circuit wires that provide the power are referred to as the line wires. L1 (line 1) is a red wire and L2 (line 2) is a black wire. Together, they show the motor voltage. Having both an L1 and L2 indicate that the motor voltage may be 240 volts.
What does T1 and T2 mean on a thermostat?
When you call up the FreezeAlarm, you can tell it to supply the low voltage power to either thermostat #1 (T1) or to thermostat #2 (T2). Whichever ther- mostat is getting power is the one controlling the furnace. To to turn on the heat, you don't need the second thermostat.
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.
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.
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.
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 is the orange wire on a thermostat?
In most thermostat wiring hookups the orange wire is used to control a reversing valve - switching from heating to cooling mode or vice-versa. See (B and O) above. R. RH and RC single power for HEAT and COOL. In most thermostat wiring hookups the red wire is the power source for the system.
What does each thermostat wire do?
Knowing what each thermostat wire does can help in wiring up a new or replacement room thermostat. This data can also be helpful if thermostat wires have become mixed-up or improperly color-coded by allowing you to trace wires back to their control connection point.
What is the wire used to control a fan?
In most thermostat hookups the green wire is used to control a fan. In most thermostat wiring hookups the orange wire is used to control a reversing valve - switching from heating to cooling mode or vice-versa. In most thermostat wiring hookups the red wire is the power source for the system.
Does a backup heat switch on a thermostat?
IF the thermostat wire bundle routed to the thermostat included enough wires to operate all of the needed functions and IF the model thermostat includes both heating and cooling, the answer is probably yes. Backup heat will typically switch on automagically depending on outdoor temperature.
Where do you put the C wire on a thermostat?
In some cases, one of those wires may be your common. If you have a C wire, place it into the C terminal on your wall plate. Let's take a look at the G wire. This wire will go to the G terminal on your new thermostat. For the Y, Y1, and Y2 wires, Y or Y1 will go to the Y terminal, and Y2 will go to the Y2 terminal.
How many wires does a thermostat use?
The thermostat uses 1 wire to control each of your HVAC system’s primary functions, such as heating, cooling, fan, etc. See the diagram below for what each wire controls on your system:
What to do if you see terminals labeled A B C or 1 2 3?
If you see terminals labeled A B C, or 1 2 3 then your new thermostat may not be directly compatible, as your system requires a communicating thermostat.
What does it mean when you see red wires?
If you see thick, black or red wires then you have a line voltage system. This type of wiring requires a line voltage thermostat and is not compatible with low voltage thermostats
Do you tape off the B wire on a heat pump?
If you have separate wires for O and B, you will want to tape off the B wire so it can’t make contact, and the O wire will be connected to the O/B terminal on your thermostat. If your O or B terminal shares a label with another wire, typically W, you’ll need to identify whether you have a heat pump system or not.
Can you label wires that are not connected to a terminal?
Any wire that is present, but not connected to a terminal you will want to make a note of, but you will not label these wires.
Where does Y1 go on a wire?
For the Y, Y1, and Y2 wires, Y or Y1 will go to the Y terminal, and Y2 will go to the Y2 terminal.
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 is orange wire?
The orange wire only applies to homeowners with an air-source heat pump. Only air-source heat pumps connect to your outdoor condenser. Homeowners with geothermal heat pumps have no use for the orange wire.
What is the white wire on a thermostat?
The white wire behind your thermostat controls the heating section of your HVAC system. It is connected between the W terminal and the heat source, a furnace, or a boiler. Many houses use dual-stage heating, which is more efficient and is quite common in modern HVAC systems.
How many wires does a thermostat have?
Most modern thermostats have the standard 4 or 5-wire template, with the only difference being whether a C-wire is present or not. However, older setups or simpler systems installed in places like cabins might use a 2 or 3 wire system. 2 or 3 wire systems usually have a single-stage boiler/heater installed. In contrast, newer systems might have air conditioners, heat pumps, etc.
What is the C wire used for?
In most modern 24V systems, the C wire is used to complete the power circuit for the thermostat if it consumes electricity . The majority of modern thermostats require electricity to operate, so a C-wire is necessary for them.
What is the E terminal on a heat pump?
This terminal is used for the emergency heating back-up in your heat pump. In case the primary heating fails, heat pumps have a smaller emergency heating in them. There is no thermostat wire color specified, but it’ll be connected to the E terminal. It is better to check what wires originate from your heat pump to see what color the wire is.
What is the green wire on a blower fan?
The green wire is connected to the blower fan relay and controls the airflow through the ducts. If you have a split system, the blower fan is indoor in the air handler, while in a package unit, the blower fan is in the outdoor unit.
What wires are used for a heat pump?
Some manufacturers such as Rheem and Ruud use the dark blue wire to connect B-terminal and the reversing valve. In this case, the reversing valve is used in heating mode.
What wire is used to connect a heat pump to a furnace?
In this case, your furnace will have low fire and high fire settings. If you have a two-stage heating system, a brown wire will be used to connect the W2 terminal to the dual-stage switch on your furnace or boiler. Heat pumps usually use staging for additional heating (auxiliary heating). In that case, the heat pump is also connected to the W2 terminal through the brown wire.
