What is a K wire on a thermostat?
The K wire is the AC and Blower wire combined. So K equals Y1 and G combined into one wire. Look at any thermostat with a K and you will see that the G and Y wires are missing. You can't put that wire into the Y2 terminal without having a Y1 you will get an error code of E39, E89 or E169.
What is the L terminal on a Honeywell thermostat?
L: This terminal is designated for indicator lights on the thermostat, sometimes for when auxiliary or emergency heat is turned on, or if there’s a general problem with your system. K: Honeywell wire saver modules combine the Y and G wires to form a single K wire that connects to the K terminal on some Honeywell thermostats.
What are the terminals on a thermostat for?
Refer to the thermostat manufacturer's wiring diagram for precise connection information. 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. RC: The RC terminal is the 24-volt cooling power supply. RH: The RH terminal is the 24-volt heating power supply.
Which wire connects to the Y terminal on a thermostat?
The wire that connects to the Y terminal is yellow and connects to the compressor in your cooling system. It enables the thermostat to control the air conditioning unit.
Where does K wire go on Honeywell thermostat?
K terminal from HoneywellFor your safety, turn the equipment off and pull the breaker down before touching the thermostat wires.Install the K wire to the G terminal of Emerson thermostat. ... Take a photo of your Emerson thermostat wiring connections. ... Go to your indoor equipment and open the door.More items...•
Where does K wire go on nest?
At the thermostat: Remove the thermostat cover panel. To be compatible with the Wyze thermostat wires K and C will need to be adjusted. Place the wire in the C terminal into the G terminal. Place the wire in the K terminal into the Y terminal.
What is the Y terminal for on a thermostat?
cooling or air conditioningY - 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 do the letters mean on thermostat wiring?
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). You can also refer to the Conductor Color Chart (see Chart 6, thermostat wire).
What wire controls heat on thermostat?
white wireIf 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 the RC wire the same as C?
The C and Rc wires are not the same. To install this thermostat you should follow the exact same wiring of the previous thermostat.
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 are the different terminals on a thermostat?
Thermostat Terminal Letters 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. RC: The RC terminal is the 24-volt cooling power supply. RH: The RH terminal is the 24-volt heating power supply.
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.
How do you identify thermostat wires?
Look for connectors that have labels that are the same as your thermostat. For instance, you might find labels like R, W, G, Y, C or O/B. You should find wires attached to these connectors that are the same color as the wires that connect to your 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.
How do you wire a thermostat?
5:5611:06Basic Thermostat Wiring - YouTubeYouTubeStart of suggested clipEnd of suggested clipInto the W terminal and the green wire into G or the fan tighten that one up as well. Okay. So weMoreInto the W terminal and the green wire into G or the fan tighten that one up as well. Okay. So we have the thermostat hooked up and then of course this wire goes into the wall and down to the furnace.
What is Y1 wire on thermostat?
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. The G or G1 wire controls your fan.
What is the common terminal on a furnace?
The common terminal is the "bridge" between the power supply and the load (typically a light fixture). With this in mind, the wire that attaches to the common terminal is either (1) a hot wire from the main board or (2) leads to the load (fixture).
What controls the water temp on a boiler?
The thermostat controls the circulator, turning it on and off as dictated by sensed temperatures in the heated space. The boiler temperature control opens to turn the circulator off if boiler water temperature drops below the low limit to maintain a minimum boiler temperature.
What is the purpose of the outdoor air thermostat?
What does the outdoor air thermostat control? It prevents operation of the electric heating elements above its setpoint.
What is the Y wire on a thermostat?
Y, Y1, Y2: Whenever your thermostat calls for cooling, the Y wire is used to send a signal to your HVAC system telling it to fire up the air conditioner. Y1 and Y2 wires might be used instead if you have a two-stage system (i.e. a high level for extremely hot or cold days, and a low level for mild days). W, W1, W2: Just like the Y wire, the W wire ...
What is a K wire?
K: Honeywell wire saver modules combine the Y and G wires to form a single K wire that connects to the K terminal on some Honeywell thermostats. It’s used for systems that don’t provide a C wire but have a thermostat that requires one.
How many volts does a thermostat use?
Note: While thermostat wiring only utilizes 24 volts (thus it won’t shock you or is even detectable), it’s still a good idea to shut the power off to your entire HVAC system before replacing the thermostat, so as not to cause any issues with the electrical system as you work on it.
What does it mean when you replace a thermostat?
If you’re replacing your thermostat for the first time, you might notice that the wires are connected to different terminals, each of which is denoted by a certain letter. Here’s what those letters mean. Replacing a thermostat is really easy, but sometimes the terminal letters on your old thermostat don’t match up with the ones on your new ...
What does C stand for in HVAC?
C: This stands for the “common” wire in an HVAC system, and it provides power to the thermostat. Some systems don’t provide this, and it’s not necessarily required by every thermostat, since some can be powered by a battery or just “ steal ” power from other wires, but if your system has one and there’s a terminal for it on your thermostat, you should absolutely connect it.
Can you replace a thermostat with a new thermostat?
Replacing a thermostat is really easy, but sometimes the terminal letters on your old thermostat don’t match up with the ones on your new thermostat. Knowing what each letter stands for and what it’s used for can help you figure out which wire goes where on your new thermostat.
What is the Y wire on a thermostat?from ifixit.com
Y, Y1, Y2: Whenever your thermostat calls for cooling, the Y wire is used to send a signal to your HVAC system telling it to fire up the air conditioner. Y1 and Y2 wires might be used instead if you have a two-stage system (i.e. a high level for extremely hot or cold days, and a low level for mild days). W, W1, W2: Just like the Y wire, the W wire ...
What is a K wire?from ifixit.com
K: Honeywell wire saver modules combine the Y and G wires to form a single K wire that connects to the K terminal on some Honeywell thermostats. It’s used for systems that don’t provide a C wire but have a thermostat that requires one.
How many volts does a thermostat use?from ifixit.com
Note: While thermostat wiring only utilizes 24 volts (thus it won’t shock you or is even detectable), it’s still a good idea to shut the power off to your entire HVAC system before replacing the thermostat, so as not to cause any issues with the electrical system as you work on it.
What does it mean when you replace a thermostat?from ifixit.com
If you’re replacing your thermostat for the first time, you might notice that the wires are connected to different terminals, each of which is denoted by a certain letter. Here’s what those letters mean. Replacing a thermostat is really easy, but sometimes the terminal letters on your old thermostat don’t match up with the ones on your new ...
What does C stand for in HVAC?from ifixit.com
C: This stands for the “common” wire in an HVAC system, and it provides power to the thermostat. Some systems don’t provide this, and it’s not necessarily required by every thermostat, since some can be powered by a battery or just “ steal ” power from other wires, but if your system has one and there’s a terminal for it on your thermostat, you should absolutely connect it.
Can you replace a thermostat with a new thermostat?from ifixit.com
Replacing a thermostat is really easy, but sometimes the terminal letters on your old thermostat don’t match up with the ones on your new thermostat. Knowing what each letter stands for and what it’s used for can help you figure out which wire goes where on your new thermostat.
Can you use emergency heat on a heat pump?from ifixit.com
It has to be turned on manually, whereas auxiliary heat can turn on automatically if need be. Emergency heat is only used if there’s a problem with your heat pump.
What is the O terminal on a heat pump?
The O Terminal is the control for the reversing valve in most brands of heat pumps. When the heat pump thermostat calls for cooling then this terminal closes and energizes the reversing valve causing it to switch from a default position of heating to a position of cooling. This is done as a failsafe for heating which is considered more important than cooling. If the reversing valve or its solenoid would fail for whatever reason you would likely still have heat. Its safer to go without the air conditioner in most cases than it is to go without the heat.
What is the Y terminal on an air conditioner?
The Y terminal is the terminal for the cooling relay in the condensing unit for your air conditioner (and heat pumps). When the thermostat calls for the air conditioner the contacts inside the thermostat close and Y gets the 24-volt power and passes it to the compressor contactor inside the condensing unit. This in turn, energizes the compressor and the condenser fan motor. The same thing happens for a heat with one other additional occurrence explained below. An addition to this terminal is a Y2 terminal for second stage cooling if the system is so equipped with 2 stage cooling.
How does a hot water boiler work?
A hot water boiler is controlled by an aquastat which cycles the boiler on and off based on the boiler temperature. There are many other ways to control a boiler but typically on a call for heat the W terminal in the thermostat closes and gets its power from the R terminal.
How does the W terminal work?
The W terminal controls the heating system. If you have a furnace or boiler then these appliances get there signal of 24 volt power from the W terminal in the thermostat. With boilers it is a little different depending on the type of boiler you have. A hot water boiler is controlled by an aquastat which cycles the boiler on and off based on the boiler temperature. There are many other ways to control a boiler but typically on a call for heat the W terminal in the thermostat closes and gets its power from the R terminal. This power usually energizes a relay that turns on the circulator pump for boiler piping loop. The water circulates through the loop and you have heat. The boiler turns on and off based on the water temperature and not from the thermostat. Furnaces are turned on by the W terminal by energizing a relay. Gas furnaces will automatically turn the indoor fan on by another control in the furnace. An addition to the W terminal is the W2 terminal which is for second stage heating. Some systems and thermostats even have a W3 for third stage heating.
What color is the R terminal on a thermostat?
A good example of this is I have opened thermostats and seen black used on the R terminal. Green used on the W terminal and red used on the Y terminal. Once you see the thermostat wire and the colors of thermostat wire that are available you will understand. As far as those unconventional wired thermostats I’ve seen, I can only think that the person was color blind. And that is giving them the benefit of the doubt. Now, on to the designations.
How does a boiler turn on and off?
The water circulates through the loop and you have heat. The boiler turns on and off based on the water temperature and not from the thermostat. Furnaces are turned on by the W terminal by energizing a relay.
What terminal is used for second stage heating?
Gas furnaces will automatically turn the indoor fan on by another control in the furnace. An addition to the W terminal is the W2 terminal which is for second stage heating. Some systems and thermostats even have a W3 for third stage heating. C Terminal.
What is the terminal for second stage cooling?
Many systems only have a single compressor but if you have two compressors which should only operate off of one thermostat then you need the Y2 thermostat terminal for second stage cooling.
What is a W2 thermostat?
W2 – This is the thermostat terminal used for second stage heat. There are gas furnaces with low fire and high fire and some depend on control from a two-stage heating thermostat with a W2 terminal. Heat Pumps use staging for auxiliary heat and need a W2 terminal.
What is the W wire?
W – This is the thermostat terminal for heating. This wire should go directly to the heating source whether it be a gas or oil furnace, electric furnace, or boiler,
What does E stand for in a heat pump?
E – This thermostat terminal is for heat pumps and stands for Emergency Heating. If for whatever reason the heat pump condenser fails and it is necessary to run the heat there is an option on heat pump thermostats for emergency heating. Basically this simply utilizes the back-up heat source many heat pumps have to heat the home without sending a signal to the condenser to run for heat.
What color wire is used for a reverse valve?
Rheem and Ruud will usually utilize the blue wire for reversing valve.
What is RH in a transformer?
RH – The RH terminal is designated for the power for heating. See RC above for an explanation. It should be noted that a jumper can be installed between RC and RH for a heating and cooling system equipped with a single transformer.
What color is the R terminal?
Red for the R terminal. *Although be aware that this may have changed especially if the person who wired the thermostat didn’t use conventional color coding.
What is the color of the thermostat wire?
When taking into consideration your thermostat wiring colors, the orange wire typically connects to the O terminal while the dark blue wire connects to the B terminal. This depends greatly on who installed it as well as who manufactured your heating pump.
How many thermostat wires are in a furnace?
Typically, a furnace plus A/C HVAC system has four or five thermostat wires and a common wire. A heat pump system, on the other hand, has eight or more different thermostat wires.
What terminal is needed for a two stage compressor?
A cooling system with two compressors or a two-stage compressor need a Y2 terminal , so the thermostat is able to control the second stage of cooling. The color of the wire varies from installer to installer, but it appears light blue is usually the go-to color for this terminal.
What is the C terminal on a thermostat?
The common wire links to the C terminal. This particular wire extends from the transformer and is responsible for completing the 24 V power circuit in the thermostat. The common wire doesn’t have a standard color. It’s usually black, but in some cases, it’s the thermostat blue wire.
What is the yellow wire on a thermostat?
The wire that connects to the Y terminal is yellow and connects to the compressor in your cooling system. It enables the thermostat to control the air conditioning unit.
Why does my thermostat have an E terminal?
When your thermostat triggers the emergency heat, it’s usually because it’s too cold for the heat pump to depend solely on the first stage heating. The price to use second stage heat alone is high.
Why do you want to take a picture of the current wiring?
You want to take a photo of the current wiring because even when you have your old device removed, you’ll still have a map of how the wires were connected to the base. You may want to mark the terminal where each wire connected.
What is a wire saver?from honeywellhome.com
The wire saver is designed to be used with applicable thermostats in which a 24V C wire is required but the homeowner does not have a C wire connected to their current thermostat. Honeywell's wire saver acts like a splitter and replaces the need for a C wire to be run from the HVAC system to the thermostat. This is the best recommendation ...
How to identify RC wires?from honeywellhome.com
Identify any wires label R, RH, or RC. You will typically have one or two out of those three. If you just have one wire, regardless if it's labeled RC, it will go into the R terminal, and the jumper connecting terminals R and RC will be in place. Some thermostats have a jumper switch, some have a metal staple, others may have a plug, and the jumper may also just be a wire connecting the two terminals. If you have two wires, R or RH will go into the R terminal, and RC will go into the RC terminal. If you have more than one wire (you have a wire labeled R, and another wire labeled Rc for example) you can remove any jumpers between the R and Rc terminals, or push the switch to open the RC terminal so you can insert a wire.
How many wires does a thermostat use?from honeywellhome.com
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?from honeywellhome.com
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?from honeywellhome.com
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
What is labeled as W and O/B?from honeywellhome.com
Using the photos that you took, remove each wire one at time and label it. If a terminal has multiple designations like W and O/B, it will be labeled as W and O/B and not just one or the other.
Where to photograph thermostat wires?from honeywellhome.com
NOTE: Photograph your connections at your thermostat and at your furnace where your wires are connected prior to disconnecting them.
