Remove the wall screws holding up the thermostat before disconnecting the wiring to prevent the wires from falling into the wall. White – The white wire is what connects to the (auxiliary) heat on your system. Complete the wire connections on the baseboard heater, if this has not already been done. You now know how to look for a c wire or common wire in your heating system wiring. The same two wires that connect the thermistor to its excitation source can be used to measure the voltage across the thermistor. Errors were found with the address you provided. Unscrew and remove the wires from their terminals. Snap the thermostat to the mounting plate. 8. .top-level { 4-Wire Thermostat Wiring Step 8. 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. 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. Heck, now I’m not calling anyone a dummy! 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. If you have heat and AC, you’ll need 18/5. Of course you can cut or extend the wires. Using wire connectors, connect a hot supply wire, which is typically black, to thermostat wire one (typically it is marked L1 or Line). Tuck the wires into the electrical box and secure the thermostat with the mounting screws. Unused C Wire Terminal. Now, loop each copper end around each terminal, and tighten the screw on the terminal. If you don’t have a “C” wire: Check the area behind the thermostat to see if a c-wire was tucked into the wall by your electrician or the installer. Determine your schedule. overflow:hidden; This new wire will serve as the C wire or common wire to provide necessary power to the thermostat. Thermistors are very simple to wire. Thermistor is a small non-linear resistance sensors, which can be embedded within the insulation of a motor winding, to provide a close thermal association with the winding.It’s made from a metal oxide or semiconductor material. Track when you leave the house (or workplace) and are away regularly for … Used in three-phase motors. It terminates in your outdoor condenser for reversing valve operation from hot to cold. Red – Now, there can be two separate wires for this. Mount the control unit to the base using the screws included with your thermostat. Running new thermostat wire can challenging even for professionals. Sometimes they employ a 3-wire construction if a ground or shielding wire is present. Installing The Wrong Thermostat Type – Always install a thermostat to its compatible base. If you have a C wire, place it into the C terminal on your wall plate. Connect the wires. Connect the remaining supply wire, which is typically white, to the second thermostat wire (typically marked L2 or Line). In this really short video you will learn how to connect an unused wire so it can be used as your C wire, which in a lot of cases has solved the problem of a thermostat not working. One is for cool and the other is for heat, hence the abbreviation “RH” and “RC”. The thermistor has to be connected to a control circuit, which can convert the resistance signal, which again has to disconnect the motor. Step 9. Tighten the screws securely. Thermostat Wiring for Dummies. For example, if the Red wire is connected to W on the thermostat … Wire the smart thermostat to the correct terminals. It is very simple and pretty straight forward. Screw the system wiring to the screw terminals on the new thermostat using the letter labels as reference (strip the wires back if necessary). So 4/4 and 5/5 when dealing with the wire setup. But what if you have a system that's a little different like a Heat Pump System, Then your thermostat is going to be wired a little different as well. Install the replacement wall plate and hook the new thermostat up to the old wires. How to Hook Up a Thermostat: Hook up the wires. Most come with two-wire connectors. If you already have a C wire in place, you just need to connect the same C wire to the new thermostat (when you replace the old model). Install new thermostat base. Reviews and General Information on Programmable Thermostats. Connect each marked wire to the corresponding terminals on the thermostat with a screwdriver. The wire will run through a dedicated opening on the side of the furnace into the control panel. When you purchase an item through links on our site, we may earn an affiliate commission. Since the resistance is pretty high (10Kohm) the wire resistance won't make a … See the diagram below for what each wire controls on your system: Y – Compressor Stage 1 (Cooling) Y2 – Compressor Stage 2 (Cooling) G – Fan C – Common Connecting to a Thermistor These thermistors are pretty hardy, you can strip the PVC insulation and stick the wires into a breadboard or solder to them directly. The orange thermostat wire links to your heat pump, if you have one. https://www.thermostatcenter.com/ is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. The main trouble is dealing with those different colored wires, knowing which one does what and if that wasn’t enough, you also have numbers and letters to deal with. Look for a wire connected to a terminal labeled with a “C” on the thermostat. Run the thermostat wire from your furnace to the location where your thermostat will hang. }, Copyright 2003 - 2019 OMEGA Engineering is a subsidiary of Spectris plc. Furnace Thermostat Wiring Diagram Terminal Letters On a Thermostat and What They Control The Hot wire (24 volts) usually Red from the transformer is the main power wire to turn on or off a furnace components. Thermostat Center is supported by our readers. If you must then following these instructions and helpful hints will hopefully help you in this endeavor. How Do You Wire Your Thermistor? Depending on the thermocouple’s type, a thermocouple’s wires may be magnetic. The orange wire connects to terminal O on your thermostat. Mount the baseplate of the smart thermostat to the wall using the provided screws. AND it has been recorded by a professional in the industry. Turn on the circuit breaker and test the heater and thermostat for proper operation. Green – The green wire connects to the fan. The resistance in the sensor remains relatively low and constant over a wide temperature band and increases abruptly at a pre-determined temperature or trip point. Even the most seasoned people who enjoy DIY may come across problems with wiring a thermostat. Yellow – The yellow wire connects to your compressor. HSTH-44000, Handheld Infrared Industrial Thermometers, Temperature Connectors, Panels and Block Assemblies, Temperature and Humidity and Dew Point Meters, Multi-Channel Programmable and Universal Input Data Loggers, Safe and precise temperature transmission and control can prevent unplanned production downtime. I will explain that in a little more detail further down this page. Complete the wire connections on the baseboard heater, if this has not already been done. Use the wire cutters to strip each wire so that there is approximately 1 inch of bare copper showing. C wire from furnace to thermostat – Source. In a three-wire installation, connect the red wire to the “R” terminal, the white wire to the “Y” terminal, and the blue wire to the “W” terminal. Prevent unplanned production downtime, Measuring Temperatures in Furnaces with Oxidizing Atmospheres, @media screen and (max-width:1024px){ Even the most seasoned people who enjoy DIY may come across problems with wiring a thermostat. Mount your new Sensi thermostat base using the supplied screws, drilling holes if necessary.] Finally, the 5 wires likely cover Red for 24-volt hot, white for heat, yellow for cooling, green for the fan, and blue for common (common could be another color). The wire colors indicate the thermocouple type. Thermistors are also available with metal or plastic cage-style element covers for air temperature measurement. } HSTH-44000. Tighten the terminal screws to secure the wires in place. What I would like you to know is the information detailed below is based on the industry standard, yet not all thermostats will work this way simply because letters and numbers are used as well as color. For more advice from our General Contractor reviewer, including tips on how to replace the thermostat in your car, keep reading! View this page in another language or region, Learn more about the  If you’re still a little confused (and I can understand why you would be), I have added a thermostat wiring made simple video for you to look at which isn’t very long but is one of the best explanations I have come across. Do not let them fall back in through the hole in … The thermostat uses 1 wire to control each of your HVAC system’s primary functions, such as heating, cooling, fan, etc. The manufacturer typically determines this property with a high degree of accuracy, as this is the primary characteristic of interest to thermistor buyers. 5-Wire Thermostat Wiring; This is the most common and covers many central air conditioners with an air handler or gas furnace. Learn more about the  Plus, I’m anything but a technician so what I have detailed below is here purely as a guideline. One of the biggest complaints, or rather, reasons for confusion I have come across is down to the fact that many thermostats on the market don’t work if your system isn’t equipped with a ‘C’ (common) wire. These letters are standard; hook them up to the same terminals on the new thermostat. Mount the thermostat base by gently pushing the excess wire back into the wall opening and plugging the hole with a fire-resistant material. The O/B wire can have many configurations. Please verify your address. Once the new thermostat is on the wall, turn power back on from the breaker. The thermostat wiring on these systems can have very similar wiring properties. If your system has both heating and cooling functions, you'll need to connect both the Rc and Rh terminals with a red wire. Thermistors are a type of semiconductor, meaning they have greater resistance than conducting materials, but lower resistance than insulating materials. Use a small screwdriver to loosen the terminal screws on the Sensi thermostat base, and insert each labeled wire into the corresponding terminal. ; this is the most seasoned people who enjoy DIY may come across with! 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