However, some heating and cooling systems and situations exist where the Nest Thermostat may need a common wire to bring power to the thermostat… be determined (for LOW VOLTAGE series 10 type circuits). However, if the system is not being used the Nest still needs to get power so it will pull short bursts of power … C wire (blue or black, common for 24-volt power to the thermostat). image.jpg image.jpg. Nest support folks say a C wire is needed. CAUTION: High voltage cables Fuse box or Switch 1. On the phone with Nest for an hour and we had to disconnect common to get them to work But now I’m concerned that the Nest batteries will be … A brown wire is mostly likely a heat pump wire and should be connected to the O/B connector on the Nest thermostat. Google improves upon the Nest Thermostat with this $130 model. However, once I installed the Nest and run … That wiring caused the Nests to continually stay in “delayed mode”. The installer could have used any color, though. O & B Terminals. This is not a problem when the HVAC system is running in either heat or cool mode. Here's how you should install your existing wires on your Nest Thermostat. Nest vs Honeywell Lyric T5 Smart Thermostat [2018 Update] Ecobee3 & 4 lite vs Nest E & 3 – Four Models Compared [2018 Update] ... It’s usually black, but in some cases, it’s the thermostat blue wire. Original Post: Nest Thermostat and C Wire. A blue jumper wire connects terminal 3 of the relay to the 24V AC common C terminal within the furnace. This wire also known as a common wire. Click to see full answer. Thankfully installing a smart thermostat without a C-wire is pretty simple. My transformer has the red and blue wires in the secondary, so there is no guessing there. Usually smart thermostat is installed with four or five individual wires. Blue – This is your common or “C” wire. Previously during the Heat, Fan, Cooling test it had come on, but in the cycling fashion described above. • If there’s an orange wire in the connector labeled both W and O/B, then you likely have a heat pump. d=, r=red, =blue. There's actually no need to connect the green wire anymore since it isn't also connected to your old thermostat. For programmable thermostats and smart thermostats, c-wires are essential for setting a schedule or having your heat or air conditioner turn on at a desired temperature.While some units can run without a c-wire, even brands like Nest … bshughes657 Member. Smart Thermostat Wiring. Nest Thermostat vs. Nest Learning Thermostat: The breakdown. I'm trying to get the nest thermostat to function with the Honeywell Aquastat L8148e. The blue wire, or C-wire, is known as the common wire.It's there to provide power to the thermostat.Older thermostats usually don't have a C-wire because they either don't need power or, if they do, they get it from a battery.. Jmosely98 said: I have a question about the blue wire … 5,655 Posts #3 • Apr 9, 2013. Then, unscrew your old thermostat’s cover, and label the exposed wires using the tags from your Nest kit. I get 24 volts at the aquastat between the Rh wire and W. Zero volts between the white wire T … Nest Thermostat G4CVZ - C Wire Not Detected by Nest, Multimeter shows 25v. I blew a small purple, two … Thermostat C-Wire is that extra cable providing extra power to the smart thermostat. Would like to connect a nest thermostat. Keeping this in view, where does the blue wire go on a thermostat? As soon as I started the testing phase I could tell it was working properly. They tried connecting the red wire that’s capped to the blue wires which are connected to the Nest Common. How to Install a 7-Wire Thermostat To install your 7-wire thermostat, first ensure you have thoroughly read all manufacturer instructions and followed all necessary safety procedures for working with electricity. If the Nest doesn’t turn on after installation and the Red LED is blinking on front, the Nest thermostat battery is low and needs to be charged. If you’re installing the Nest Thermostat and aren’t connecting it to any cables within the wall, then you’ll need to: NOTE: The Stand for the Nest Learning Thermostat is sold separately 20. yellow wire connected to “Y”, white wire connected to “W”, and so on), but sometimes that isn’t the case, and you might have something like a blue wire connected to “Y”–like I do in the photo below. The Problem is the Heater Has Short Cycles when heating. ... (Like the other Nest thermostats, this model does not require a C-wire to operate. When the thermostat does that, it displays a message that there is something wrong with the furnace. Use a Common Wire With a Nest Thermostat (or Suffer the Consequences) Technology Editor Bill Wong takes some unwanted time to replace his Nest thermostat … This time the AC compressor turned on only during the … Installing a Nest learning thermostat involves removing your old thermostat, and wiring in the new one with Nest’s simple kit. In the above image, a “Blue” coloured wire is coming into terminal marked “C”. Customer reply replied 1 year ago. • Common or C wires are generally blue. Some people have no problems whatsoever, the nest in my office/store doesn't have it connected, been like that for years, no wifi drops, no problem. I discovered the wire was there, just wrapped around the wiring sheath and unused. (but requires a c-wire for Apple HomeKit functionality) ecobee3 ; ecobee3 lite; ecobee4; Sensi Wi-Fi Programmable Thermostat; Sensi Wi-Fi Thermostat (but requires a c-wire for Apple HomeKit functionality) Even then, the Nest uses a battery that may … Each wire coming out of the wall should go into a specific labeled port on your old thermostat (R, Y, W or G, for example). It fixed everything. There is a stand alone air handler in the attic. I’ve just spoken to nest tech support and told her that I only have a 2 wire system and she seemed very confident that they will connect to the C and NO and that the … Usually “C wire” or the Common Wire will be a blue coloured wire. My wires are Rh and W1 from the Aquastat and Rc and G and Y1 from the air handler. any help is - Answered by a verified HVAC Technician Likewise, does the Nest Thermostat need AC wire? This portion of the heat pump … The Nest is working perfectly now. Put this wire in the Nest Thermostat’s * O/B connector. The one in my house will drop wifi if the unit doesn't run at least once every couple of hours and when the nest … It causes issues with the Nest thermostat’s operation. Search for 8 Wire Thermostat To Nest here and subscribe to this site 8 Wire Thermostat To Nest read more! In many ways, some would say the most important ways, the Nest Learning Thermostat and the Nest Thermostat are the same thermostats. Then, what is the blue wire on a thermostat? There is a blue wire that I had assumed was the "C" wire, but looking at the furnace, it doesn't look like that's the case, as the blue wire looks like its connected to the W2 terminal. 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. But there is no particular standard for thermostat wires, so it can be any color like Yellow, Brown, Green or any other color. I still don't recommend this thermostat with or without a blue wire. The reversing valve in a heat pump system connects to the O & B terminals. Nest used to claim that their thermostats would work without a C-wire because the circuitry uses the voltage provided by the R-wire to charge an internal battery when needed. ... Nest Thermostat E; Honeywell Lyric Round 2.0. the trane thermostat has three wires connected. Hi again, can I just clarify that this is a nest thermostat E that uses the heat link at the thermostat with nothing fitted to the combi boiler itself (obviously the thermostat connects to the boiler at that point). If there is a common wire installed the Nest Thermostat will not power share. Start by turning off the circuit breaker for your thermostat to avoid electrocuting yourself. Below are the basic steps you need to follow to install a smart thermostat without C-Wire. • If there’s a white wire in the connector labeled both W and O/B, then you probably don’t have a heat pump. Each of these wires has a name featuring a single letter (listed below). You may also have up to two black wires as well but these are used for various heating systems in the North or for outdoor purposes, so for most of you these won’t need any attention. If you don't, you'll need two red wires so you can connect each terminal separately to the system transformer. I then need to factory reset the thermostat. Next I attached the yellow wire coming from the transformer to the yellow wire running down from the thermostat. If you're unsure about your C-wire … Put this wire in the Nest Thermostat’s W connector. Actually factory resetting your Nest Thermostat when uninstalling it from the wall is an option not a must, but it is good to factory reset it if you are moving to a new place. The thermostat black wire connecting to the Nest’s * connector, controls the operation of the humidifier. “C Wire” coming into thermostat – Look “Blue” wire in ‘C’ terminal – Source. Welcome to Google Nest Community Forum. I matched up all wires from my old thermostat, which did not have a C wire connected. Switch off mains power You’ll be working with high voltage cables, so protect yourself and the thermostat by turning off the power … But the Nest Thermostat does not show the Blue wire connected on the Equipment Detected Page of the Nest Thermostat. The common wire, sometimes referred to as the c-wire, is what’s responsible for delivering constant power to your thermostat. Every now and then it takes over the control of the furnace and the furnace won't stop unless I turn off the power to the furnace. The blue wire completes the 12-24 volt circuit so the nest receives full power 100% of the time, even if the hvac isn't running. Thanks! A wire marked 'G' is typically green, while 'O' is orange and 'B' is blue. From what I can tell, all I need to do is cut and splice the blue wire of the 24 vac transformer to my blue wire in the thermostat wiring, and then provide the other end to the nest connection. I hooked up the blue wire to the common and then plugged it into the “C” on the Nest base. Every time, it has been the thermostat… Most of the time, the color of the wire will correctly correspond to the letter of the screw that it’s connected to (e.g. I just got a Nest E thermostat and I'm trying to hook it up. I put my multimeter across R and C (the previously unused blue wire) and got 25v AC. Click to see full answer. The black of the 18/8 thermostat wire connects to terminal 1 of the relay mounted inside the furnace. Whether you have an Ecobee, Nest Emerson or some other smart thermostat, the same principles will apply. Can I do what I am proposing to do to fix my lack of a "C" wire problem for my Nest thermostat… Power sharing, I have found, to be a pain in the rear. Once you’ve labelled the wires, remove your old thermostat … Find your 8 Wire Thermostat To Nest here for 8 Wire Thermostat To Nest and you can print out. Looking at the photo you shared, it seems that you have a 2- wire heating system. After removing … Turn off the power ; Remove the faceplate; Detatch the backplate from the wires; Plug in the C-wire … If the B wire is blue, it should most likely be connected to the C connector.