Blue Wire Thermostat

Atwood Hydro Flame thermostat - solution I have digital thermostat and owners manual recommendeds 68 using furnace and 72 using AC. How to Install and Set Up the Nest Thermostat. Pull the thermostat body off the thermostat base. If there is no wire, you don't have a c wire and will probably want to get one. C - BLUE WIRE = Not used on RTH2300B. You have been selected to participate in a brief customer satisfaction survey to let us know how we can improve your experience. When all of your existing. But that's not always the case. At the furnace end both power wires were connected to one terminal. Examine where the wires are connected to the thermostat's terminal screws. Get free 2-day shipping on qualified Thermostat Wires products or buy Electrical department products today with Buy Online Pick Up in Store. If there is a wire connected, note its color and go back to your thermostat. wire is actually light blue. The thermostat has five wires brown=live blue=neutral green=earth black=compressor and a white wire. Replacing thermostat by yourself without a Denver HVAC technician can be pretty harrowing if you do not hook up the wiring correctly. inside unit thermostat outside unit. thermostat terminal / wire control and supply wiring (oem / vendor) ceiling assembly terminal designation r or red one red, (+) 12vdc supply wire to the thermostat n /a b or blue two blue, one (-) 12vdc supply wire to the thermostat and one blue wire to ceiling assembly / plenum b y or yellow one yellow, compressor control wire to ceiling. So, your accurate wiring is:. Free Wire Configuration. Electrical Question #2: How is a Honeywell Thermostat wired? I am trying to rewire a 5 wire Honeywell thermostat. ) Remove the old wallplate only afterall wires are labeled. Pay your bill, report an outage, start or stop your service, and explore energy saving programs. So I did the same with the new thermostat. Not sure? Contact support. Attach the blue stickers in the Nest installation guide to the. When I took the front off the current honeywell thermostat, it looks like there are quite a few more wires than what the new thermostat will accept. Question - thermostat Honeywell, TH3210D1004-0914 OR BAR CODE Red-R, Yellow-Y, Orange-O, green-G, Blue-C, white-Aux (install a jumper wire. Thermostat Wiring Guide - How To Do it Right In this article, I am going to explain to you how to wire a thermostat in your home. The RH (Red Heat) connects to a red wire, the green wire connects to G, and the white wire connects to W. red, white, yellow, green, black or blue. I installed this myself and I'm no stranger to wiring. The Rc wire connects to the cooling system. C is common or blue to the HVAC world. For ALL Mechanical / Technical Questions concerning your Chevrolet or GMC vehicle which you can not find within some of the manuals on this site, Please ask or post on one of the online forums such as:. The O thermostat terminal is for this purpose. My current thermostat has 4 wires hooked up: one to Y, one wire to G, one wire to W, and one wire to RH with a jumper between RH and RC. be easy and I should take the red wire from terminal L in my existing thermostat and put it in terminal A on the new thermostat, the blue in N I. Discuss Replacing Room Thermostat 3 wires to 2 wires?? in the Central Heating so is it safe to just chocolate block off the blue wire then and leave it hanging. Once this is completed, connect the wires per the diagram and notes below. Thermostat Terminal Designation: Color of Wire and Termination*: R - The R terminal is the power for the thermostat. > Otherwise, with battery it only lights when you touch it and then > remains on for 15 secs or so. If you count 5 wires, you’re good-to-go. There are only four wires going into the existing thermostat - red, green, blue, white. 18 GAUGE THERMOSTAT WIRE - STRANDED SIZE (AWG) / NUMBER OF CONDUCTORS. I've read many posts regarding the lack of a blue (or "Common") wire running from the furnace to the thermostat, but I can't seem to find the conclusive answer as to what can be done to fix or work around this. Plug the 2 blue wires that are provided into the their matching. Breaker box Switch Two labels Tip: Take a picture of the wires on your old. Thermostat Wire Reference Chart List of the control function of each ID label or color of room thermostat wires. PROPANE GAS. Questions about the C-wire are by far the biggest drivers of traffic to this site, so I've written this article to. This wire also known as a common wire. B and O together Trane heat pump products. Normally, the blue wire in the bundle is used for a common wire. I am replacing my old Honeywell round gold thermostat (mercury bulb) with a new digital programmable one. No C wire in this example. Do not use C or X. This terminal may already have a wire connected to it but it may not be a wire that goes to the thermostat f. com sells some of the most energy efficient and innovative thermostats you can buy. NOT SURE WHAT YOU NEED? Give us some basic information about your project and we'll have one of our experts build you a custom quote and answer all of your questions. Hi, You do not need it if you have the green wire hooked upElectric Water Heater Wiring Diagram How to replace the Thermostat. By closing the circuit, it delivers constant 24-volt power to your thermostat. If there is no wire, you don’t have a c wire and will probably want to get one. We address them in order from most common to least common. In the best case scenario, you will find five wires (red, green, yellow, blue, and white) and maybe even a sixth wire that is black. Wiring—heat pump Connect wires: heat pump 1 Match each labeled wire with same letter on new thermostat. But if this. If you have a digital thermostat now, you MUST pay particular attention to any wire placed at the C terminal on the thermostat. I called honeywell and sent them these pics. iThis terminal may already have a wire connected to it but it may not be a wire that goes to the thermostat f. Smart Thermostat Wiring. So I did the same with the new thermostat. PROPANE GAS. Heat pump thermostat wiring - A typical wire color and terminal diagram. differential on a thermostat is. the color of the 5 wires on a 5-wire thermostat isolation circuit will most likely be. Here's what you need to know. 240 Volt Solar Controller Circuit Diagram. You can also use. Panel Wizard. This new wire will serve as the C wire or common wire to provide necessary power to the thermostat. Installing your new thermostat? Lowe's even has all the accessories you need to get the job done, including thermostat wire and thermostat covers. If you only have 4 wires they are typically (Red, Yellow, Green & Black). R - Red, W - White, Rc - Yellow, C - Blue. So what about the heat pump thermostat? If you have a heat pump you don't have a furnace since the heat pump provides cooling and heating. Snip off thermostat wire-end connectors-if the power-in wire is rigid copper wire, instead snip off 2-3 inches away from original connection to save some stranded wire for a wire-nut. At the furnace end both power wires were connected to one terminal. INSTALLATION INSTRUCTIONS SINGLE STAGE ELECTRIC FAN THERMOSTAT PART # 16735 (Continues on reverse side) KIT CONTENTS QTY. Some of the other wires powering your thermostat include: R-wire – Power, usually red. In all likelihood, as thermostats continue to develop that are going to need more wires rather than less. But there is no particular standard for thermostat wires, so it can be any color like Yellow, Brown, Green or any other color. Plug the 2 blue wires that are provided into the their matching. Honeywell Prestige wiring requirements) need a minimum of 5 wires, and maybe more depending on what features you want to operate (humidifier, etc). Problem is that I have a red, a white, a green and a blue wire. 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. New home owner. Initial setup and. Find the 24 VAC common terminal identified with C, X, B, or COM. thermostat 1 2 4 branch circuit to electrical distribution panel 1 upper thermostat & high temp. About thermostat wire. You are eligible for a full refund if no ShippingPass-eligible orders have been placed. Hi, please could someone help, I have read & searched but to no avail. Installation is Easy Label wires and remove your old thermostat Install and wire your new thermostat Set your new thermostat to match your heating/ cooling system - It is preset for the most common system We are here to help. After installing one I discovered that it called for heat but never shut it off. CT30/CT33 Low-voltage Thermostat 3 Label wires and remove old wallplate Use a screwdriver to disconnect wires one by one. You might check the wiring for shorts or as a simple test try substituting the blue wire with a spare if there is one available. Take note of the terminals that the wires are attached to. If you have a digital thermostat now, you MUST pay particular attention to any wire placed at the C terminal on the thermostat. Attach the blue stickers in the Nest installation guide to the. In theory I had "no c wire" either but had 2 power wires, 1 for AC and 1 for heat. Back in the olden days, thermostats were simple on/off devices that didn't need their own continuous power supply. Because many thermostats come with a pre-installed thermostat jumper wire that connects these terminals, you only need one red wire, which could be the thermostat Rc wire or the Rh wire. If you have (Blue, White & Blue stripe, Orange, White & Orange stripe, and possibly Green & Brown pairs as well) coming out of the wall then it is probably phone or networking wire and it isn't good because it is too thin for the current. do i … read more. We don't seem to have a common wire, so I'm hoping we can maybe turn the blue or brown wire into a common so that the nests can get power other than when the HVAC is actually running. Many thanks. The temperature controller built into the AC unit itself is pre-installed by the manufacturer and requires no user wiring. Millivolt and 3-wire hydronic zone valve compatible; White Rodgers Blue. If your system has both heating and cooling functions, you'll need to connect both the Rc and Rh terminals with a red wire. So the G wire here does control the HVAC fan. online searching has now gone a protracted means; it has changed t. I have been Honeywell RTH 230 B thermostat. White – the white wire will connect to the heat on your system. There are a number of different 3-way wiring configurations that you may come across and need to know how to wire. ecobee thermostats require a C (common) wire to power on. Save on printer ink and toner to keep your office efficient and productive. A lot of campers come with an old fashioned analog thermostat like the one pictured here. View File Consumer Literature 3 · View File Installation Instructions ·. • Remove the red wire from the 24-volt side of the transformer’s secondary side. If your old thermostat is labeled 120V or 240V or has thick wires with wire nuts, your system is high voltage. most likely a System Common wire. Each individual conductor is sheathed in a protective, flexible coating of a different color. Remove Old Thermostat Before removing wires from old thermostat, mark wires for terminal identifi cation so the proper connections will be made to the new thermostat. Millivolt does not contain wiring for power, so that has to be managed as well. (If you’re checking the air conditioning, only the blower will go on. The Good Ecobee's $249 Ecobee4 Smart Thermostat has a responsive display, a remote sensor and tons of smart integrations, including a built-in Amazon Alexa speaker. limit (eco) upper heating element blue junction box l2 red 4 black blue black lower thermostat tm 1 black tm 2 g* g*g * branch circuit to electrical distribution panel upper thermostat & high temp. Dave’s Reply: Thank you for your electrical wiring questions. The blue wire is stripped. The old mercury thermostats did not require any power. Thermostat Schematic Wire colors. Rangemaster - Britain's best loved range cooker brand. Forcing or prying on the thermostat will cause damage to the unit. What's a C-wire, and why should you care? The C, or "common" wire can make -- or break -- your thermostat installation. If there is no wire, you don't have a c wire and will probably want to get one. Step 1 - Install the Thermostat * Wire down and fix the Thermostat in the boiler room. Locate all unused (disconnected) wires from the thermostat wire bundle and write down the colors. 24 VAC Furnace wire terminals Furnace cover. This information is designed to help you understand how the thermostat functions, how to set up a new thermostat, thermostat wiring, and configuring it to work with your current HVAC. I am going from a Rehau thermostat with four wires (red, white, dark blue, green) to a Tekmar 561 thermostat. Whether you need to replace an old broken thermostat or want to upgrade to a better one, it is a low-cost and quick project. There are a number of different 3-way wiring configurations that you may come across and need to know how to wire. Types of Thermostat Programming. Checking your existing system for a common wire is easy. Usually "C wire" or the Common Wire will be a blue coloured wire. Modern thermostats have many extra features that need additional power such as a large screen or wireless connection. C wire (blue or black, common for 24-volt power to the thermostat). Reader question: I just picked up a new Trane programmable thermostat for our air conditioner/heat pump system. It's heat and air conditioning, and the old thermostat was a pretty basic, older round variety (also honeywell). The temperature controller built into the AC unit itself is pre-installed by the manufacturer and requires no user wiring. CAUTION: When removing thermostat, don't let the wires slip into the wall and don't let the wires touch each other. If wires will be connected to both R and Rc terminals, remove metal jumper. If you have (Blue, White & Blue stripe, Orange, White & Orange stripe, and possibly Green & Brown pairs as well) coming out of the wall then it is probably phone or networking wire and it isn't good because it is too thin for the current. thermostat wire bundle and write down the colors. I am installing a new NEST thermostat, replacing an old two wire mercury bulb furnace thermostat. The current connections on my old round thermostat are as follows: W = White wire for Heating G= Green wire for fan relay to energize blower fan R= Red wire for power to thermostat Y= yellow wire for air conditioning and a mysterious blue wire that. Inside of the thermostat there are several terminals which must hook up with the right wires. i24V Common wire is typically (not always) colored blue Unused wires Thermostat wire bundle c. At the furnace, the unused wires are not connected to anything--shown here at the bottom. The three wires are red, white, and blue or yellow, depending on the manufacturer. At the beginning of Nest Learning Thermostat 3 rd Generation, you have to check the compatibility with your heating or cooling system. Thermostat/Terminal Wire Control and Supply Wiring (OEM/VENDOR) Ceiling Assembly Terminal Designation R or RED One Red, 12 VDC (+) Supply Wire to the Thermostat N/A B or BLUE Two Blue, One 12 VDC (-) Supply Wire to the Thermostat and One Blue Wire to Ceiling Assembly/Plenum B Y or YELLOW One Yellow, Compressor Control Wire to. The O thermostat terminal is for this purpose. Try Terminal 1 = Red Terminal 2 = Blue Terminal 3 = Yellow If you have a meter, check the voltage between 1 and 2 with the stat set low; it should be 230v. 5 Amps maximum load (all terminals combined) Standard Systems Gas, Oil, Electric Single Stage/Heat Pump Millivolt Systems Thermal Specifications Setpoint Temperature Range:. Introducing ZLINK! ZLINK, conceived and executed by industry experts with deep experience in Home Control, Building Management, and Independent Living, exists to bring to market high-value, innovative solutions that complement the existing field of Z-Wave products. Try Terminal 1 = Red Terminal 2 = Blue Terminal 3 = Yellow If you have a meter, check the voltage between 1 and 2 with the stat set low; it should be 230v. com sells some of the most energy efficient and innovative thermostats you can buy. Reply Delete. The O thermostat terminal is for this purpose. Follow the instructions below to determine if your home has the required 24 VAC Common Wire. The most common configuration for thermostat wiring is: Green - fan wire. The blue wire on the old tstat was connect to a C terminal. We offer a variety of thermostats to fit your unique needs and lifestyle. First with the power off I connect the optional common wire up to the thermostat. During installation, the wires are connected to one board that sends certain data through each wire to the thermostat. Get Started > The Circuit Wizard app is available for Android™ devices & iOS devices. Here's what you need to know. Is it a common? I looked at the wiring in the SMZ box but cannot tell what the B terminal is going. Problem is that I have a red, a white, a green and a blue wire. If your old thermostat is labeled 120V or 240V or has thick wires with wire nuts, your system is high voltage. Now I can't get either one to work. It is only used on thermostats that are powered by the transformer. Nest & Other Power “Sharing” Thermostat Wiring Options Notes: Wiring applies to Digital Energy Manager (shown) and Classic Energy Manager with red labels used on System 2000 and 90+ Resolute™. In the wall, there are only 2 wires. First oder of business was to replace old round thermostat with new digital. The wax (blue) is inside a sealed chamber (gray) that contains a metal needle (silver). It seems to me that the terminals are designated with the first letter of the color wire connected to it. This complete 24-volt thermostat wiring guide covers all thermostat wiring issues from the simple to the complex. What Do Electrical Wire Color Codes Mean? Yellow and blue electrical wires are also used to carry power but are not for wiring the outlets for common plug-in. Basic Thermostat Types. I also have a tan wire which was not connected to anything. Windy City Wire is the industry leader in cable management solutions, offering labor savings at every phase of the cable management process from concept to completion. (Typically the blue wire). • If your old thermostat has both an “O” and a “B” wire present, then “B” is likely a System Common wire and may be connected to the “C” terminal. G - Fan (green wire). A C wire adapter (common wire adapter) is basically a small electronic device, which re-purposes the existing wiring between your thermostat and the furnace, to add a new wire to the system. The O thermostat terminal is for this purpose. To deselect a ball just click on another. Modern thermostats with Wi-Fi and backlit display, by contrast, need a steady supply of juice. The wires are blue,green,white,orange and red. Discuss Replacing Room Thermostat 3 wires to 2 wires?? in the Central Heating so is it safe to just chocolate block off the blue wire then and leave it hanging. In common with most coach accessories in an RV, the thermostat that controls the air conditioner (AC) is a regular household unit. Here's what you need to know. your old thermostat had 2 C or C1 wires, wrap each separately with electrical tape and do not connect them. I added some wiring labels to make this easier to read. Screw on the mounting plate, thread through the wires, and attach the thermostat in place of your old one. Thermostat Wires Color Coding. Call 1-800-468-1502 for wiring assistance before returning the thermostat to the store. If you are reinstalling another digital or programmable thermostat you will reuse this wire. The C wire, or "common wire" enables the continuous flow of 24 VAC power to the thermo. The most common configuration for thermostat wiring is: Green - fan wire. Some covers pull off while others need to be released. The blue wire on the thermostat is the Common or "C" wire. Now I can't get either one to work. View and Download White Rodgers 1F89-0211 installation and operating instructions manual online. tENC-408 t tt ttt Enclosures Thermal Management 1-800-633-0405 Compact Thumbwheel Thermostats Wiring Diagram Inches [mm] Dimensions Please see our website www. About thermostat wire. R - RED WIRE = RTH2300B R terminal leave jumper installed between R and RC. Breaker box Switch Two labels Tip: Take a picture of the wires on your old. Wires on control thermostat wrong. If the old thermostat was a mercury style thermostat, dispose of it properly as described below. Then I open up the air handler and locate the transformer. As previously mentioned, Alan's wiring documentation (his was a Coleman) DID NOT work on my unit, so bare in mind that some wiring changes may be necessary to make the Hunter Digital thermostat function properly with your particular system if they are different than the two referenced within this article. Initial setup and. 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). Emerson 1F80-0471 Thermostat User Manual. There are a number of different 3-way wiring configurations that you may come across and need to know how to wire. Use the Blue Sea Systems Circuit Wizard to select the correct wire size, circuit breaker or fuse type and amperage, and fuse holder. So you’ve decided to install your new thermostat and discover that you have an unused wire but you do need a C wire connection. C terminals are connected to the common wire, which is most often black, but can also be other colors. As you disconnect each wire, wrap it with the label matching the letter on your old thermostat. Reading from top down, green wire on the G post, yellow wire on the Y post, white wire on the W post, red wire on the Rc post, blue wire on the R post. 1F78-151 Thermostat pdf manual. How to set up your ecobee. Typically, a furnace plus A/C HVAC system has four or five thermostat wires and a common wire. An Aprilaire whole-home dehumidifier extracts the right amount of moisture from your home to help prevent the health problems caused by high humidity. After installing one I discovered that it called for heat but never shut it off. To replace a three-wire thermostat, connect each of the three wires to the right connection. Not sure if the W2/Y2 jumper is even needed from the research I done, it appears my Trane XL15i hvac is 2 stage heat and 1 stage cool. In our lab tests, Thermostat models like the Blue Easy Reader 1F95EZ-0671 are rated on multiple. Remove old thermostat cover Remove the cover using a screwdriver or by pushing the pressure latch. R- Red wires to Ts and HP O - Orange wires to both B - Blue wires to both W1 - Black and white wires to Ts, Black wire to HP. Call 888 750-ALFA toda. Installing a Nest learning thermostat involves removing your old thermostat, and wiring in the new one with Nest's simple kit. My old thermostat is a Trane and my new thermostat is a Honeywell Programmable digital WiFi touchscreen model RTH8580WF. Call 1-800-468-1502 for wiring assistance before returning the thermostat to the store. I am having difficulty understanding where the four wires go on the Tekmar 561. The terminals on the rear are marked NO (red wire connected) COM (Yellow wire connected) and NC (nothing connected). This is a common problem when replacing a mechanical thermostat or a thermostat powered by batteries. At the furnace end both power wires were connected to one terminal. White Rodgers 1F89-0211 - Non-Programmable Blue Thermostat, 2/1HP - Features 2-square-inch Blue display with easy-to-see characters Exclusive Cool Savings feature saves energy during peak A/C demand periods Long battery life uses 2 AA alkaline batteries (included) Exclusive battery power monitor 5-year warranty Easy push-connect color-coded. C - BLUE WIRE = Not used on RTH2300B. Can somebody advise which ones are required please. this for a coleman mach thermostat model 7330 335 heat/cool the problem is i don't know where blue wire connects to there is two solid white wires one white wire with red stripe and the blue wire the other wires i think i am good. Discard it. limit (eco) upper heating element junction box 1 3. Use the Blue Sea Systems Panel Wizard to design and order a Custom 360 Panel. Known for rugged dependability and tremendous value, our products stand the test of time. blue wire, no polarity furnace thermostat white wire into street-side roof n/c. Here's what you need to know. We have both a natural gas furnace and an AC unit. the new thermostat has white, red, yellow, green, blue terminals. The exact number of colored wires varies, as does the gauge of the wires. Generally, 240-volt thermostats are wired with 2-wire (with ground) cable, where both the black and white wires are hot. Some programmable thermostats (e. (Typically the blue wire). Always remember thermostat wiring used to be rated for 110 volts but now modern systems are rated for 24 volts. Separate the fuse and it's wires from end to end-make certain to view which end is which looking at thermal element inside the clear plastic shield 6. your old thermostat had 2 C or C1 wires, wrap each separately with electrical tape and do not connect them. As shown in the diagram, you will need to power up the thermostat and the 24V AC power is connected to the R and C terminals. Sea Frost 148 Old Concord Turnpike Barrington NH 03825 Tel: (603)868-5720 Fax: (603) 868-1040 [email protected] Personally I ran my Hot lead to the W terminal (with white wire) , Then the R terminal was connected T1 on my Zone Valve (Red wire). If you have (Blue, White & Blue stripe, Orange, White & Orange stripe, and possibly Green & Brown pairs as well) coming out of the wall then it is probably phone or networking wire and it isn't good because it is too thin for the current. Ideally, the HVAC professional that installed your system used standard colored thermostat wire, and connected the wires to the terminals that match the wires’ color. Usually, this common wire is blue or black, but be advised that many electricians are “creative” when it comes to using wire colors!. If they are connected incorrectly, the thermostat can burn out. The c wire provides 24vac power source. The orange wire is for reversing valve to energize the Heat Pump in cooling mode. The information provided is intended for references purposes only. Forgot to take note of how old thermostat was wired. In this configuration, the blue wire acts as the return wire between the 24V transformer in the heating/cooling system control panel and the thermostat. The thermostat has a total of four wire leads: two marked LINE that connect to the circuit feed wires, and two marked LOAD that connect to the circuit wires leading onward to the heater. Wiring Options Considerations. Questions about the C-wire are by far the biggest drivers of traffic to this site, so I've written this article to. Thermostat Wiring and Wire Color Chart. Common configurations found in houses that are covered in this guide are: 4 Wire Heating and Cooling - Rh/Rc, W, Y, G. The Nest Learning Thermostat shows eight blue rotating dots during startup It’s normal for the Google Nest Learning Thermostat to display eight blue rotating dots during start up. I connected the red/white wire from P1-1 to the red wire from P2-2, and soldered those two wires to the red solid wire that goes to either RH or RC on the Si. Those both energize the reversing valve in heat, as most other brands energize it in cooling. Blue Sky Solar Controller Network. 1F80-0261 Thermostat pdf manual download. The red wire was connected to "Rc" terminal, green to the "G" terminal, white to the "W" terminal, and blue to the "Y" terminal. Snip off thermostat wire-end connectors-if the power-in wire is rigid copper wire, instead snip off 2-3 inches away from original connection to save some stranded wire for a wire-nut. This complete 24-volt thermostat wiring guide covers all thermostat wiring issues from the simple to the complex. I am replacing my old Honeywell round gold thermostat (mercury bulb) with a new digital programmable one. These older thermostats require 4 wires, but newer more sophisticated thermostats require a 5th wire known as the Common wire to power the digital display. One is for cool and the other is for heat, hence the abbreviation “RH” and “RC”. Not sure? Contact support. Orange (pulse) - HVAC system is actively heating. There are only four wires going into the existing thermostat - red, green, blue, white. warning! this is a ford motor company private computer system. I'm unsure if my furnace (Amana GUIS070CA35) is actually two stage or not. Related Posts to Honeywell Thermostat Wiring Color Code. That's because the thermostats I bought lack support for the third wire (B, blue) on my Honeywell V2008A zone valves, the wire that closes the valve. A thermostat's terminals are marked with "Y," which is usually a blue wire, "W" is a white wire, "G" is typically black, and "R" is red. After one year with this connection and one particular annoying issue, I found out the Nest thermostat only needs one (or the other) connected. com for complete engineering drawings. This is typical wiring for most units. Great! Diligently reading the new unit's manual it informed me that the plate to which all the wires were connected on the old thermostat would have labels not unlike that of the proteins in DNA -- individual letters that may or may not have anything to do with the wire colors. So you've decided to install your new thermostat and discover that you have an unused wire but you do need a C wire connection. But it appears the brown wire and blue wire do nothing. thermostat 1 2 4 branch circuit to electrical distribution panel 1 upper thermostat & high temp. C terminals are connected to the common wire, which is most often black, but can also be other colors. on the inside unit you have green, white, blue and red control wires. WIRING CONNECTIONS. I am going from a Rehau thermostat with four wires (red, white, dark blue, green) to a Tekmar 561 thermostat. I need help! This is the wiring setup on the Air Handler terminal block. The additional 5th wire will be for common; providing stepped down power from a transformer. We address them in order from most common to least common. Some of the other wires powering your thermostat include: R-wire – Power, usually red. I nstalling a new programmable thermostat is easy to do and can save you money by using less energy. Here's what you need to know. It's a wire that (if you have one) runs all the way from your furnace to your thermostat. Unlike many thermostats, smart or not, the Ecobee4 comes with one remote sensor. Always remember thermostat wiring used to be rated for 110 volts but now modern systems are rated for 24 volts. Connect thermostat wire Never check for leaks with an open flame. Blue - This is your common or "C" wire. On the old one both the Yellow and Blue wires are connected to the Y screw. DESCRIPTION 1 Blue 5/16” Ring Terminal 3 Blue #10 Ring Terminal 2. Hi, You do not need it if you have the green wire hooked upElectric Water Heater Wiring Diagram How to replace the Thermostat. Snip off thermostat wire-end connectors-if the power-in wire is rigid copper wire, instead snip off 2-3 inches away from original connection to save some stranded wire for a wire-nut. The trouble is, the c-wire is not that common in many (older) homes, as a traditional thermostat didn't require much power. R - Red, W - White, Rc - Yellow, C - Blue. Breaker box Switch Two labels Tip: Take a picture of the wires on your old.