The basic Heat + A/C System thermostat typically utilizes only 5 terminals. After years of owning and running A smart home installation company I’ve realized that the information we’ve learned can be helpful for people who want to take on smart home projects on their own. As in the previous cases above, this Honeywell round t-stat utilizes the same wiring color code guide. In the setups we’ve seen, the most common wire color code guide for single stage climate control thermostat follows. ecobee3 Smarter Wi-Fi Thermostat with Remote Sensor, 2nd Generation. 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. White Wire = W = Heating Wire . Which Wire Is Ground. Open the HVAC unit by removing either on or both covers. In many cases, a bundle of these colored wires will be grouped together, and sealed within a black or grey cable. It does not have the G wire. Yellow Wire = Y = Cooling Wire Amazon's Choice for 4 wire thermostat. The picture above depeicts the typical wiring color code for a 4 wire thermostat. The blue, brown, or black wire (C) connects the low side of the output of the furnace transformer. 4 Wire Thermostat Wiring Color Code. 4 Wire Thermostat Wiring Color Code. In the setups we’ve seen, the most common wire color code guide for single stage climate control thermostat follows. 3 Pole Switch. Also, these particular t-stats need a C wire. … The Blue, Brown, or Black Wire. Name: 4 wire thermostat wiring diagram – How to Install Honeywell thermostat with ly 4 Wires Best Brown Wire thermostat Trane Heat; File Type: JPG; Source: firedupforkids.org; Size: 228.05 KB; Dimension: 836 x 768 For this reason, kill the power at the condenser and the air handler before changing or working on the wiring at the t-stat. So the Red Wire or R wire provides power to the thermostat and system for control. Even the most seasoned people who enjoy DIY may come across problems with wiring a thermostat. C – 24 VAC Common (You might see blue, purple, or brown typically used for this wire). We opted instead for the remotely programmable capabilities of a Wi-Fi smart thermostat that needs a C wire. 4 Wire Thermostat Wiring Color Code It also will feature a picture of a sort that could be seen in the gallery of 4 Wire Thermostat Wiring Color Code. 2002 Ford F250 Radio Wiring … This helps to protect people from accidental exposure, and makes it much easier to run the wiring where it needs to go, especially for higher voltage situations. Most people don’t use the “fan only” mode, so while you’d give up control over the fan in the system, you’d gain constant power to the smart thermostat. The blue wire is known as the neutral wire and its job is to take electricity away from an appliance. The t-stat connects this lead to the R wire whenever it calls for the air conditioning to come on. Wiring. Learn how to automate you life with a smart home, Our smart home blog to help you automate your life and smart home. 4 Wire Thermostat Wiring Color Code Uk have a graphic from the other. When wiring, each wire should be identified by what terminal(s) it connects to, never by color. To access the HVAC system control board you need to turn off the HVAC system either with the switch on the side of the unit or at the control board. See this shown below in the units we’ve wired. $15.99 $ 15. We also teach you how you can control your Nest Thermostat with voice in another post using Alexa. R – 24 VAC usually a red wire (Rc and Rh are discussed later) 3. Then, we had to move the green wire from the G to the C terminal on the furnace wiring block. The above is a typical wiring diagram of a Nest Thermostat with 4 wires. The red wire (R, RC, RH) connects the high side of the output of the control transformer to the t-stat. 4 Wire Thermostat Wiring Color Code. The diagram below shows how a basic 4-wire thermostat is connected as indicated by the color code chart above. The wire color codes used are only going to apply to the actual wires that are carrying the electricity. The brown cable – known as the live wire – actually delivers electricity to your appliance. If that is the case there is one way to determine what the right wiring is. If you don’t have a common wire, Ross recommends wiring the G wire into the common port instead. This is commonly found in standard HVAC systems that use an air conditioner and a furnace. Smart thermostat’s are a great investment, just take your time when installing your new smart thermostat and you should be fine. So even if they used the wrong color wiring, what ever wire is connected from R on the furnace terminal to R on the thermostat terminal will provide power. The best thing to do is to take a picture before you start your project so you know what wiring was there. 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