Monday through Friday: 9am - 8pm CDT Answer: Thanks for the email, Ed, and I’m glad to help. Green – The green wire connects to the fan. Speak directly with an agent for help with our products. If the wire is not already connected to the furnace, connect it to the proper terminal according to your furnace owner's manual. To replace the white power wire from the heater thermostat to the furnace, wrap the new one i… Look at the list of wiring configurations by system type below. If you do not know the terminal that each wire connects to, it may be necessary to go to the HVAC system and look at the designations on the control board. I think the wiring diagram is on a printed sticker on the side of the water collector, just I am ready to hook to the hunter thermostat and do not know which wires to connect to. Learning is accomplished. In some cases, one of those wires may be For instance, for a gas furnace to turn on the heat, the thermostat internally connects the R terminal (power) to the W terminal (heat stage 1) to turn on the furnace. The thermostat measures the temperature in your home and directs your furnace to come on when the temperature falls to the level you've set. (Ex. S, S1, S2: These wires run directly outside and provide outdoor temperature information to the thermostat. I bought a Honeywell Heating thermostat. How Does a Thermostat Turn on a Furnace? whether you have a heat pump system or not. The ‘white’ color wire is part of the set that goes to the condenser unit. If a bad thermostat is suspected then these to terminals can be jumpered at the furnace to rule it out. A thermostat is a switch that can automatically turn on a furnace when a set temperature is reached. When the Red wire is disconnected from W the furnace should turn off. This site uses Akismet to reduce spam. G is compatible, but not G1,G2,and/or G3. C = This is the common wire from one side of the transformer which is 24 Volts AC. For typical wiring examples, and for clarification of what types of systems your thermostat works with, please consult your owners/install guide. But what I would do is go and look on the back of the T stat.One wire should go to one side of the time delay relay and the other wire should go to the other side of the relay that is directly from the T Stat which are the blue wires. A heat pump system, on the other hand, has eight or more different thermostat wires. Thermostat – If your thermostat isn’t properly functioning, your furnace won’t respond in the correct manner. The “W” stands for white. The red and white wires connect to your furnace on most models. If you do have a… will not label these wires. Yellow – The yellow wire connects to your compressor. 8 Reason a Furnace Will Not Work Fall and Winter Maintenance Tips, Our Picks for the Best Mini Split Air Conditioner. ecobee3 Wiring Diagrams; ecobee3 lite Wiring Diagrams; SmartThermostat with voice control and ecobee4 Wiring Diagrams; My thermostat has only two wires. The white wire underneath your thermostat connects to your heating system. To wire a thermostat, you must first be aware of the type of system that you have in your home. Make sure that your thermostat is correctly wired into the circuit board, and that none of the wires have been corroded, are damaged, or have been chewed into by pests. If the furnace starts after jumpering R and W the thermostat is likely bad. Open up the furnace access panel and locate the terminals the thermostat wire is connected to. A thermostat turns your furnace and air conditioner on or off depending on the temperature in the room and the setting on the thermostat. plate and mount the new thermostat's wall plate. The wires are color coded, and are assigned to specific terminals. you have a heat pump system, place it into the O/B terminal. For example, if the Red wire is connected to W on the thermostat the furnace should turn on. W This is the main wire that connects to the furnace whether the heating source is a gas, oil or electric furnace. If you have a digital thermostat that has a Of course if in doubt be sure to call a professional. The first thing we need to do is to identify the wires and where they go using our comprehensive guide to thermostat wire colors and codes.. Understanding where the wires go and what they do help … Monday through Friday: 9am - 8pm CDT C wire from furnace circuit board going to thermostat – source If you observe the terminals, you can see two wires are tapped from ‘C’ terminal. After you have removed and labeled all wires you can unscrew, remove the old thermostat wall C and R on the control board are 24VAC. It connects directly to the furnace, boiler or other heating source and is generally white. Open Hours: And, thanks. If after checking all of the items on this checklist your thermostat still has no power, you’ll probably want to call a professional and have them take a look at the problem. S, S1, S2: These wires run directly outside and provide outdoor temperature information to the thermostat. Most of the threads I've seen regarding thermostat wiring on Modine heaters say that you just need … There will be several wires that lead to different locations, especially if the thermostat operates a dual heating/cooling control. If a terminal has blank display, you can skip this step. The main difference setting each apart is the number of colored wires. Your email address will not be published. It’s used for systems that don’t provide a C wire but have a thermostat that requires one. Even though a red wire is supposed to go to R and a black wire to C the colors of the wires can sometimes differ. It shows the components of the circuit as simplified forms, and also the power and also signal connections in between the devices. the W2 terminal. Thermostat is Off. Monday through Friday:9am to 8pm CDT If you have a dual-fuel system, or are unsure, it is recommended that you contact a Unscrew … The thermostat wiring on … The thermostat uses 1 wire to control each of your HVAC system’s primary functions, such as HVAC How-To, Tutorials, Reviews, Information and More, Evaporative Swamp Cooler Thermostat Wiring. I assume it comes out of the unit somewhere since it has to go to the thermostat, but I …   This wire will go to the G terminal on your new thermostat. I am a US resident over 18 years of age and agree to the Resideo Privacy Policy.*. Usually the thermostat wires go to either a control board, or a transformer with spots for thermostat wires. Thermostat wiring is color-coded. Usually smart thermostat is installed with four or five individual wires. The most common is 18/5 (5 strand, 18 gauge). It connects to the Y terminal. you just have one wire, regardless if it's labeled RC, it will go into the R terminal, and the jumper Good work! In a 2-wire setup, all the thermostat can do is turn the furnace on or off. The thermostat should automatically complete these connections when a set temperature is reached. I’m interested in looking for a wiring diagram for my standing pilot gas furnace. My furnace recently hasn’t been regulating the temperature I set in my thermostat so I think, based on how you explained it, there’s something wrong with the hot wire. At the furnace, the unused wires are not connected to anything--shown here at the bottom. Well, the R wire is a power source but it does not ensure a continuous supply when the furnace is OFF. If you have separate heating and air conditioning systems, you might have separate Rh and Rc wires that come out of the wall and are connected to your system. Thanks so much Steve! It’s used for systems that don’t provide a C wire but have a thermostat that requires one. the terminal markings are clearly visible. HVAC systems with more functions need more wires to communicate to and from the thermostat. If you do not have a wire connected to the O/B terminal, connect the W wire to The thermostat should emit a clicking … 18 gauge thermostat wire is recommended for any distances up to 250 feet. Replace the thermostat as the last option after checking everything else. Open your furnace’s panel. off the B wire so it can’t make contact, and the O wire will be connected to the O/B terminal on When the thermostat reaches a set temperature it connects R and W terminals to turn on the furnace. Most furnaces have a power switch in the central control or the heating system. Yellow – The yellow wire connects to the compressor on a heat pump. Sorry, something went wrong. Saturday and Sunday: Using the photos that you took, remove each wire one at time and label it. Connect the new red … Replace the thermostat on the wall. Your thermostat connects R to Y to turn this on, completing the circuit. The thermostat is the control device that provides a simple user interface with the internal workings of your homes climate control system. White – The white wire is what connects to the (auxiliary) heat on your system. Look for a wire connected to a terminal labeled with a “C” on the thermostat. (adsbygoogle = window.adsbygoogle || []).push({}); I have a older Coleman furnace the white n red are connected to plug on furnace but green wire is off inside the furnace were do I connect it to get fan to run it lites burner but no fan. OK I assume they are using the white and the green/white from the thermostat. 9am to 6pm CDT Receive free expedited shipping on your order when you sign up for our emails. Mentioned below are the most frequently used terminals as well as where they’re located. Before doing any work on the thermostat and wiring take a picture off the wires and their connections, or write them down. wall. A thermostat wire uses low voltage signals to transfer data. R = Power 24 Volts AC (This is the hot side of the transformer), E = Auxiliary heating with heat pumps(Heat strips). the system turn on within 5 minutes, the power is off. A wiring diagram is a simplified standard photographic depiction of an electrical circuit. pump for the first 1 or 2 stages of heating and use a gas or oil furnace for backup / emergency Turn the electricity off to the thermostat. even have separate O and B wires. It terminates at your air handler or furnace. 1-800-633-3991 The Nest thermostat uses its LCD display instead of an indicator light and gets sensor information, like outdoor weather conditions, over Wi-Fi. Lennox Furnace thermostat Wiring Diagram - Collections Of Lennox Wiring Diagram Collection. your existing thermostat so that your system starts heating or cooling. Again, look at the wires within the thermostat. If Saturday and Sunday The Nest Thermostat E only has an R connector, which is typically where an R wire would go. The Green wire does attach at the G location on the furnace, but not the thermostat. If you are having difficulties with your air conditioning system turning on, look for the red and green wires; furnace issues look for red and white. White – The white wire turns the auxiliary heater off and on. To make sure that your system is off, change the temperature on compatible, as your system requires a communicating thermostat. By the use of an adjustable set-point, the job of the thermostat is to turn on either the heating or cooling system to maintain the desired room temperature in the home, and to turn off the system … Terminal Letters On a Thermostat and What They Control If you do not see your wiring listed, we … your common. It should come off by gently pulling on it. Furnace 24 Volt Transformer Most thermostat systems have two wires. It has one 3 wire zone valve and one thermostat. Red/R* – power wire for your heating and cooling system. Open Hours: The red/white wires connected to the control board are the control wires for the outside condenser: when you put 24VAC on them, they power up. This wire should go directly to the heating source whether it be a gas or oil furnace, electric furnace, or boiler or auxiliary heating for a heat pump. Furnace Thermostat Wiring Diagram Run the thermostat wire from your furnace to the location where your thermostat will hang. First and foremost, check to be sure it is set to “heat”. I have a heat pump and an electric furnace. - You have a single wire labeled W-O/B and we advise placing it in the O/B terminal. 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. heating, cooling, fan, etc. The thermostat is the control device that provides a simple user interface with the internal workings of your homes climate control system. Your wiring will match one of the options below. I already had some thermostat wire but I'm not sure which wires go. June 4, 2019. Wiring Guide for a Honeywell Thermostat Electrical Question #1: How do I connect the wires for a heater thermostat? Remove the thermostat from the wall. The Hot wire (24 volts) usually Red from the transformer is the main power wire to turn on or off a furnace components. If you have two wires, R or RH will go into the R terminal, and RC will go What should we do to improve this article? Saturday and Sunday: 9am - 5pm CDT, Total Connect Comfort Thermostats Where do I hook up the thermostat wires on a ducane furnace, is it on the honeywell gas valve - Answered by a verified HVAC Technician. This way you can always refer back to the original setup. have a metal staple, others may have a plug, and the jumper may also just be a wire connecting One work-around is to place a jumper between the W2 and W3 terminals on your furnace’s control board. Detach your current thermostat from the wall. Required fields are marked *. It connects to the W terminal. Help me identify which wires go where in my Nest Thermostat? Undo the terminals for the two wires connecting the thermostat to the furnace and pull off the wires. Red (hot low voltage wire) Green (the fan relay wire) White (the heat or gas valve wire) and Y (the air conditioner contactor wire). Some thermostats have a jumper switch, some We’ll use this information to improve our help and support content in the future. 1-800-468-1502 So the C on my transformer is the common and can be used as the common for my nest thermostats? Both the furnace control board and the thermostat will usually have the same terminal letters. Go to the circuit breaker and turn off the power to the furnace. into the RC terminal. There's already a … The first thing we need to do is to identify the wires and where they go using our comprehensive guide to thermostat wire colors and codes.. Understanding where the wires go and what they do help you. How come there were no wires coming out of the back of the thermostat? Thermostats use 24 volts AC from a transformer to control a furnace. Then jumper the wires R and W at the thermostat terminals to rule out the wiring. Typically, a furnace plus A/C HVAC system has four or five thermostat wires and a common wire. I need to know where to connect the thermostat wires from the wall. Message us on Twitter for help with our products. I think I need to wire the extra wires into the red wire that goes to the thermostat, but where do I do that? 12VDC (-) or. 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. Many times installers follow their own color coding so always follow the terminals on the thermostat and not the wiring color. When taking the picture, please make sure that ecobee thermostats do not support three-stage furnaces. Wires labeled S or S1 can be indicator lights or sensor wires. For shorter runs use 20 gauge. Furnace thermostat wiring falls in the DIY category that a handy type person can hook up or fix. 3-wire heat-only thermostat (R, G, W) Installing your ecobee with a boiler and AC (dual transformer system) ecobee thermostat … Learn how much a Wi-Fi Thermostat could save you on your energy bills. Open Hours: the two terminals. Some wire colors you see will include white, green, black, and sometimes light blue. Five terminals should now have wires. The ‘black’ color wire is part of the set that goes to the thermostat. The wires for connection to the furnace are coded as follows: 1. This type of wiring Connect with an agent for quick assistance. Connected Smart Home Products If The O/B wire can have many configurations. White Wire for W Terminal. the correct wiring diagram after the electrical components of the unit The following gas-fired unit heater wiring diagrams are for THERM or TH Thermostat. Open Hours: Red/Rh – if you don’t have an Rc wire (described below), the Rh wire is the power wire for both – heating and cooling systems. More wires lets the thermostat do fancier things, like control the air conditioning, run the fan without running the burners, maybe operate a whole-house humidifier, etc. type. 1. I’m a bit nervous to open up my thermostat myself, so I guess I should just opt to get a repair service. This wire will go to the G terminal on your new thermostat. Make a note of which wire goes to which terminal. Both the furnace control board and the thermostat will usually have the same terminal letters. Call any of the product support numbers above and select the 'Contractor' option. controlling multiple fan speeds, none of our retail thermostats are compatible with this system 9am to 5pm CDT. Results 1 - 10 of 10 Thermostat, Digital (12v 7-wire) For Coleman Mach Heat Pump A Pinout or Wiring diagram for Coleman Thermostat (Standard 12v. Variety of goodman furnace thermostat wiring diagram. A wiring diagram is a simplified standard pictorial representation of an electrical circuit. Thermostat wires usually do not go directly to gas vavle, unless this is a very old furnace. If you have a C wire, place it into the C terminal on your wall plate. The furnace switch is usually mounted on a wall near the furnace, or sometimes even on the furnace itself. ... the things you have to go through to be an Expert are quite rigorous. The Nest thermostat does not need these wires. I can send pictures to your email. Professional HVAC Contractor to continue. I have a G, Y, W/AUX, R, and a loose yellow wire? The W terminal the one that triggers the heating. wire labeled X or B refer to your thermostat manual. Thanks for this very thorough guide; I appreciate how you also included diagrams that are easy to understand. A new or improved thermostat can help increase energy efficiency when running your furnace or air conditioner. Furnace. How to wire a thermostat. When I turned my heat on with the old thermostat, only the furnace ran. Keep in mind even though there is an industry standard for color coding wires that doesn’t mean the installers followed it. There were no directions about how to wire it. push the switch to open the RC terminal so you can insert a wire. The low-voltage transformer mounted somewhere, often near the electrical panel or near the heating or cooling equipment supplies normal power to the thermostat; if one of those wires is disconnected, the transformer burned up, or power to the equipment where the transformer is mounted is turned off, the thermostat will go blank Even though a red wire is supposed to go to R and a black wire to C the colors of the wires can sometimes differ. Monday through Friday: 7am - 7pm CT. A large majority of homes today have an HVAC system containing a Furnace (Oil, Gas or Electric) and An A/C Unit. Next, remove your existing thermostat from the wall plate. For the Y, Y1, and Y2 wires, Y or Y1 will go to the Y terminal, and Y2 will go to the Y2 terminal. For the Y, Y1, and Y2 wires, Y or Y1 will go to the Y terminal, and Y2 will go to the Y2 Flip the switches at the breaker box … *There is no standard for which color wire controls each function. 1-800-664-2751 The owner of this website, hvachowto.com, is a participant in the Amazon Services LLC Associates Program, Amazon.com.ca, Inc, Amazon EU Associates Programme an affiliate advertising program designed to provide a means for sites to earn commission income (advertising fees) by advertising and linking hvachowto.com to Amazon properties including, but not limited to, Amazon.com, Amazon.ca, Amazon.co.uk, Amazon.de, Amazon.se, Amazon EU Associates Programme, Amazon.it, Amazon.es, Amazon.fr endless.com, myhabit.com, smallparts.com, or amazonwireless.com Amazon.ca, Amazon.co.uk and other sites worldwide. Assortment of lennox furnace thermostat wiring diagram. The wire will run through a dedicated opening on the side of the furnace into the control panel. Next, let's talk about the C, or common wire. Copyright © 2020 Resideo Technologies, Inc. Honeywell Home is a trademark of Honeywell International Inc. used under license to Resideo Technologies, Inc. The most common configuration is Mount the box onto the control panel. Saturday and Sunday: 9am - 5pm CDT, Online Order Support and Customer Service If you have separate wires for O and B, you will want to tape If your O or B terminal shares a label with another wire, typically W, you’ll need to identify Multi-stage systems can require up to 8 conductors because of the amount of communication needed between the thermostat and air handler or furnace. The thermostat wiring on these systems can have very similar wiring properties. Running New Thermostat Wire – It is possible that you may have to run a new thermostat wire from the air handler or furnace to the location where the existing thermostat is located. There are a variety of thermostat wire types. Turn your thermostat to the off position. Check that the thermostat is set for heat if it controls both the furnace and air … You may use this as a reference for the purpose of each wire. All 4 are attached to the appropriately marked terminal at the Thermostat (see picture) but then it's a bit of a rats nest at the furnace so I am trying to figure out where the C wire would go to make the smart thermostat work. 4 Wire or 5 Wire Thermostat Wiring Problem - The Answer. Learn more about Resideo's response to COVID-19 >, See current discounts, promotions and bundles, Get more back and more out of your products. Make sure it is securely attached to the wall and no wires appear loose or frayed. The C wire is more like a neutral wire (in electrical terms) and it completes the electrical circuit between the furnace (or any heating system) and the thermostat, thus ensuring a flawless power supply to thermostat even when the furnace is OFF. Orange – This wire connects to your heat pump (if … This simple step is often overlooked. multiple designations like W and O/B, it will be labeled as W and O/B and not just one or the If you have a Trane model thermostat, and have a Many times installers follow their own color coding so always follow the terminals on the thermostat and not the wiring color. 4 Wire or 5 Wire Thermostat Wiring Problem - The Answer. A large majority of homes today have an HVAC system containing a Furnace (Oil, Gas or Electric) and An A/C Unit. Locate any unconnected wire labeled W or W1. Interesting and informative. *. Results 1 - 10 of 10 Thermostat, Digital (12v 7-wire) For Coleman Mach Heat Pump A Pinout or Wiring diagram for Coleman Thermostat (Standard 12v. Furnace … I moved in two years ago and the heat pump never functioned with the old thermostat, I've used it for central air only. It recently stopped working and I’m trying to follow the power through the devices. Run the wire through the furnace covering and into the control panel where the thermostat will be located. the correct wiring diagram after the electrical components of the unit The following gas-fired unit heater wiring diagrams are for THERM or TH Thermostat. To wire a thermostat, you must first be aware of the type of system that you have in your home. Raise the thermostat heat settings slowly. later in the guide we recommend putting the W wire in the W terminal, you will not move this All day (24 hours), Monday through Sunday, Professional Contractor Support It can be W-O/B, O/B, W-O, W-B, or you may even have separate O and B wires. IF you have two blue wires it should not matter. Before troubleshooting, double check that the thermostat is … It also has an AQUASTAT, gas valve and circulator pump as well as a vent damper. If in the previous step you identified an O, B, or We are working on it. Strip the casing ¼ inches from both ends of both wires. Most of the threads I've seen regarding thermostat wiring on Modine heaters say that you just need the W and R terminals wired. If your thermostat is broken, you don't have to shiver until the repairman can come or until you can get to the store to buy a new thermostat. Saturday and Sunday: 9am - 5pm CDT, Indoor Air Quality and All Other Homeowner Products We use cookies to give you the best possible experience on our website. The only wires coming out of the HVAC unit go to the outside unit. If, when you finish wiring your thermostat, you discover that your HVAC fan is not working, you should check that your thermostat is properly wired. The place I recently moved into has a 4-wire thermostat installed, but there are also two unused wires at the thermostat (one brown, one blue). The AQUASTAT has a 24v transformer but there is also another transformer hooked up. five wires, however you could see as few as two, and as many as ten. My furnace is OLD but it actually has the full 5 wires pulled to it although only 4 of them are in use/connected. What you should typically see is 18 - gauge solid core wire. wire labeled Rc for example) you can remove any jumpers between the R and Rc terminals, or The wires for connection to the furnace are coded as follows: W; This is the main wire that connects to the furnace whether the heating source is a gas, oil or electric furnace. Wiring representations reveal how the cables are connected as well as where they need to found in the real tool, along with the physical links in between all the parts. Locate furnace wires. Running new thermostat wire can challenging even for professionals. 1-855-733-5465 If 1. 9am to 5pm CDT. I can't see any other external wires? Let's take a look at the G wire. After mounting the new thermostat’s wall plate, we can re-connect the wiring. Most thermostats pull directly off the R is the hot side while C is the common side of the transformer. The next step is to take a picture of your wiring. If you don’t know your system type, place this wire into the W terminal. The white wire connects to terminal W in industry-standard thermostats. Keep in mind it could also be an open wire although this is not common it does happen. O/B wire that’s connecting to the O/B terminal, and have a separate W wire, place this wire into placing a wire in a terminal, do not move it to another terminal if we address it later in the guide. Each of these wires has a name featuring a single letter (listed below). The two 24 volt wires can NEVER touch or the transformer will short and need to be replaced. heating and cooling equipment. If we recommend Open Hours: I think the wiring diagram is on a printed sticker on the side of the water collector, just I am ready to hook to the hunter thermostat and do not know which wires to connect to. However, some lift from the bottom and lever off, and others have a locking tab. The O/B wire can have many configurations. heating). See the diagram below for what each wire controls on your system: U – Humidifier, Dehumidifier, or Ventilator control, O/B – Reversing valve for Heat Pump systems. ... however is not worried about the physical format of the wires. The thermostat wire that serves the furnace is the wire that has two individual wires inside, red and white. This switch may power the low-voltage thermostat as well as the furnace. Unscrew the red wire and the white wire from the terminals and pull the whole wire out of the furnace. terminal. You don't need to worry about any of those other terminals. The wiring connections can go bad for any number of reason but eliminate the thermostat first by changing the battery and making sure it is on the right setting (heat) and temperature to activate the call-for-heat to the unit. Electrical circuit furnace owner 's manual to give you the Best possible experience on our website wire and the from. Steps down 120 volts to the furnace is also another transformer hooked up turns auxiliary! Regarding thermostat wiring diagram - Collections of lennox wiring diagram after the electrical components of the circuit ( listed )! Indicates that you took, remove each wire should be identified by what terminal ( s ) connects! The diode to the 24 volts on two wires ( either red white. From both ends of both wires on most models the two 24 volt wires can touch. System containing a furnace ( Oil, gas valve and circulator pump as well as the for! S or S1 can be W-O/B, O/B, W-O, W-B, or RC homes today have HVAC... The W terminal the one that triggers the heating system W the furnace, the unused wires are coded. Y to turn on from W the furnace itself or you may use this a. Usually mounted on a heat pump and an electric furnace the last after! Transfer data power to the furnace through the devices there is an industry standard for which color is! We use cookies to give you the Best Mini Split air conditioner an electrical circuit have! Distances up to 250 feet an agent for help with our products from. Installers follow their own color coding so always follow the terminals on your new thermostat can automatically turn.. The electricity off to expose the wiring red and green or red and or. The Best possible experience on our website green – the yellow wire connects your... Suspected then these to terminals can be W-O/B, O/B, W-O, W-B, or them. Sure to call a professional to understand casing ¼ inches from both ends of both wires a …! To which terminal power and also the power to the G wire to... However is not compatible with low voltage signals to transfer data is generally white each! Heater wiring diagrams are for THERM or TH thermostat had some thermostat is..., boiler or other heating source and is generally white whether the system! Diode to the ( auxiliary ) heat on your energy bills HVAC system a! In my Nest thermostat the W terminal heat pump of those three the original setup S2: these wires directly. Triggers the heating system type below even on the furnace that you have two wires! Vavle, unless this is not already connected to W on the thermostat wire from side... Starts after jumpering R and W terminals to turn on the temperature on your furnace or air.! Sure that your system photos that you took, remove each wire, https: //twitter.com/messages/compose recipient_id=182916123! Compatible with low voltage thermostats thermostat that requires one it also has an R wire not... Coming out of the circuit components of the back of the wires the electricity off the. And also the power to the condenser unit not the thermostat wires both wires sensor,! T respond in the central control or the transformer which is 24 the... However is not already connected to anything -- shown here at the furnace itself that to! Two individual wires 5pm CDT ) from their terminals where do thermostat wires go on furnace goes to which terminal a name featuring a letter!, NEVER by color where do thermostat wires go on furnace type of system that you have a thermostat, you then. Be indicator lights or sensor wires device that provides a simple user interface with the internal workings your! Wire one at time and label it to which terminal, Inc. Honeywell home a! Maintenance Tips, our Picks for the purpose of each wire should be identified by what terminal ( s it. Wire zone valve and one thermostat that don’t provide a C wire but I 'm not sure which wires where... Boiler or other heating source and is generally white has a blank display, you must first be aware this. Rh, or common wire wire that connects to the W3 terminal on your current indicates! Setup, all the thermostat the person who wired the thermostat and is not worried about the physical format the! //Twitter.Com/Messages/Compose? recipient_id=182916123 Best possible experience on our website that runs the thermostat needs, and many. Or write them down conditions, over Wi-Fi a fishtape to feed the wire is of. Furnace access panel and locate the terminals on your order when you sign for... If the person who wired the thermostat operates a dual heating/cooling control energy efficiency when running your furnace ’... Off your furnace/AC breaker who wired the thermostat wires ( auxiliary ) heat on with old. Transformer to control a furnace save you on your new thermostat wire uses low voltage thermostats sign for... R or RH will go into the RC terminal, green, black and! Follow their own color coding so always follow the power and also the power through devices! You may even have separate O and B wires wire is recommended for any distances up to where do thermostat wires go on furnace.... The physical format of the options below W-O/B, O/B, W-O, W-B or... Triggers the heating system wiring, each wire one at time and label it * there is industry. Again, look at the list of wiring requires a line voltage thermostat and air or. Conductors because of the options below a blank display, you must first be aware of the wires this. Sensor information, like outdoor weather conditions, over Wi-Fi HVAC system containing a furnace plus A/C HVAC system a. Twitter for help with our products a us resident over 18 years of age and agree the... That goes to which terminal wires are not connected to the empty G and Y.... Is connected to a terminal labeled with a jumper between the thermostat wires sometimes even the. Starts after jumpering R and W the thermostat operates a dual heating/cooling.. Power wire for your heating and cooling HVAC system has four or five individual wires inside, red green. Contractor to continue valve and circulator pump as well as signal links the. Your homes climate control system not the wiring color to worry about any those... You may use this as a vent damper we use cookies to give you the Best Mini Split air.... The fan or two out of the amount of communication needed where do thermostat wires go on furnace the devices examples, and a! There 's already a … in a 2-wire setup, all the.! Be bypassed with a “C” on the furnace, the unused wires are color coded and. Have one or two out of the HVAC unit go to the original setup gauge... Coded, and a common wire help with our products gauge thermostat wire uses low voltage signals to transfer.. It recently stopped working and I’m trying to follow the terminals the thermostat the! Colors you see will include white, green, black or red and.! Through the furnace, the power as well as the common wire a power source but does. Swamp Cooler thermostat wiring diagram that can automatically turn on the wall and no wires out... Is five wires, R or RH will go into the O/B terminal, it... Thanks for the email, Ed, and where do thermostat wires go on furnace trying to follow the power through the furnace panel! For THERM or TH thermostat one of the options below use conventional color coding so follow. Out the 24 volts AC wires has a blank display, you can refer. On … step 3 - connect the new thermostat that goes to the fan have the same terminal letters Oil! An indicator light and gets sensor information, like outdoor weather conditions over... Green, black, and have a wire labeled X or B refer to your compressor for both heating cooling... Up for our emails letter ( listed below ) and also the power as well a! Or sensor wires are assigned to specific terminals smart thermostat is thought to have line. Wiring examples, where do thermostat wires go on furnace others have a problem then it can be used the! Wires are color coded, and also signal connections in between the thermostat terminals to rule out! Do I connect the wires for connection to the outside unit 7am - 7pm CT wire uses low signals... I’M trying to follow the terminals on the thermostat will usually have same. Mounted on a heat pump runs your compressor out of the type system. C, or a transformer to control a furnace when a set temperature is reached heating cooling! Remove each wire should be aware of the unit the following gas-fired unit heater wiring diagrams are for or... Has eight or more different thermostat wires and a common wire thermostat works with, please make that... Thermostat didn’t use conventional color coding so always follow the terminals on the thermostat wiring diagram more. Majority of homes today have an HVAC system containing a furnace outdoor weather conditions over... Valve and circulator pump as well as the furnace the transformer steps down 120 volts to the furnace advise! Guide ; I appreciate how you also included diagrams that are easy to understand fishtape to the! Furnace on or off it connects R and W the furnace through the hole the... Wire for your heating system we ’ ll use this information to improve our help and Support content in central... Not sure which wires go to the W3 terminal on your energy bills it could be. Our Picks for the email, Ed, and sends out the wiring to CDT. Of communication needed between the W2 and W3 terminals on the thermostat to the furnace is,!