If not contact Honeywell and ask them for assistance. Yes, I admit, it is an outdated unit as I procrastinated installing it for 5-years or so.Gas boiler system is more than 50-year sold.If you have an answer I WILL donate.Norm (not lazy, just slow to pull the trigger). Tom,I bought one of these thermostats and found out I do not have the 24VAC common either. The red and white wires from the thermostat (as marked in the pic) are connected to R and G. It looks like instead of W, G is being used. I will be at the AHR show in Chicago next week and will be stopping by Honeywells booth to give them a piece of mind on making this information available. Once your c-wire is ready, follow these steps to install your new thermostat. The base plate of the thermostat comes with a metal jumper connected between Rc and R, it looks like a small staple. You are lucky that Honeywell gave you help. HVAC: red to R, white to W, green to C, blue to blue ( add a wire unit). Yet another thought is I might leave my old Honeywell Mercury thermostat and its wiring in as a backup. I have a question In to Honeywell as to how I have power one rth9580 draws. Hi All, I bought a WiFi tstat that needs a "c" wire. Power comes into the thermostat on a wire connected to the transformer, which is usually red, and returns to the transformer on the C-wire, which is usually blue, but it can be black. I can run it from the wall outlet up to the smart thermostat? The Rc terminal is used for connecting the cooling relay. Then I stripped off about 3/4" from the ends of the 4 remaining wires. ), ( ** Check the wattage requirements of the new thermostat and the output wattage of your existing 24vac transformer. ), ( Wire stripper (if you're not comfortable stripping wire with a wire cutter), Precision flat-head screwdriver (Like from the. I have a Control-4 thermostat only handling the heat connected to a gas boiler. I used all new wiring because I need to snake the other wires through the wall and it was easier to use the old wires to help bring the snake down the wall by pulling on the wire. comments, Simple Contemporary Black Nightstand Plans, How To Make Square Cuts In Dimensional Lumber, 24 Volt AC plug-in transformer (I used an, 18 gauge thermostat wire. That's what I need to eliminate. Like this article? Make sure you have enough fish tape unreeled to reach down to the other end of the opening. A device that draws less power can work with a higher rated transformer, just not the other way around.The transformer I connected hasn't had any issues. Using the app on my phone I can adjust the thermostat from anywhere. Watch an easy solution to install a wifi thermostat without a c (common) wire. One is for cool and the other is for heat, hence the abbreviation “RH” and “RC”. DoItYourself.com®, founded in 1995, is the leading independent It has a transformer and relay in it. ), ( I made sure to unspool enough wire that when I pulled the end upstairs the spool will still be on the ground so that the weight of the spool wouldn't pull the wire back down. Unless the system is OLD line voltage controls with big wire nuts or millivolt control there is no risk providing an external 24 vac source between the C-Rh. To concur with another post, for my system the transformer needed to be connected to the RH and C terminals; didn't work connected to the RC terminal. Finally I securely wrapped the connection using electrical tape and tugged on it a few times to make sure it wouldn't come apart while pulling the wire through the wall. Is this new wire connected directly from thermostat to the boiler or does it need to be cut at the junction box. The "C" wire provides the needed power. In this case If I blew that switchboard I'd be out $300 instead of a $15 transformer. Success! In other words, I need for my motors/pumps to receive power ONLY if BOTH switch 1 AND my thermostats (switches 2a and 2b) are closed ... and I further need for this setup to run in such a way that the thermostats (2a and 2b) are NO LONGER IN SERIES with switch 1. Great article! Venstar ACC0436 2-Wire Kit for all 24VAC Thermostats Lux Products LPB-WH Power Bridge Provides 24V AC Thermostats in HOmes without C-Wires Google Nest Thermostat Trim Kit - Made for the Nest Thermostat - Programmable Wifi Thermostat Accessory - Snow Red/R* – power wire for your heating and cooling system. I guess it's hit or miss. My system is simple natural gas water boiler. I needed a total of 4 conductors so I purchased the. I even tried to connect a known 24v source to the terminals on the face play ... nothing. If you do have an Rh and an Rc wire, the Rh wire is the power wire for your heating system. I tried to do what you're intending on an old 2-wire setup with a new electronic t-stat and the t-stat would only power up from the R and C terminals, the RC connection was not usable as a power terminal. ), Honeywell Wi-Fi Programmable Touchscreen Thermostat (RTH8580WF1007/U), Southwire 50 ft. 18/2-Gauge Thermostat Wire 64162179, Stanley 66-039 6-Piece Jewelers Precision Screwdriver Set, Gardner Bender EFT-21PN 25-Foot Cable Snake Steel Fish Tape, 51 Any advice on achieving the same results with a nest thermostat? I have no problems or concerns with the 24V aspect ... getting a 3-wire 24V line to the thermostats is not a problem. See the link in the "What you'll need" section to see the transformer I used.Hope that helps. I'm going to leave out certain (unimportant) details in the below ... so if an HVAC expert is reading this, this is just a disclaimer that I'm not going to mention all parts of the system. lambition, you are spot on. There are batteries, but they're only intended to power the electronics of the thermostats for very short periods where power is out system-wide ... typically a few hours. ), ( suggestions. 6 The boiler is in the basement whereas the thermostat is right above on the first floor (wire going up to the thermostat inside a pipe). Thank you for this article! That makes my life so much easier, I will also make sure the other end of the green wire is connected to "C" in the boiler. Even when set up as a 2 wire wifi thermostat. I am looking to get a wireless thermostat and will need to add a C wire. So I should be good with three thermostats plugged in. 1. See: http://www.amazon.com/Venstar-Wireless-Thermostat-2-wire-Kit/dp/B00755BZZC/ref=cm_cr_pr_pb_t Although the kit is for the Venstar thermostat, it states that it can be used with other thermostats that require an external transformer. If your current thermostat uses only two wires (R and W, or T and T), there are a few installation options available, depending on your application. The reason for this is if something is miswired, major damage could be done to your system.What I recommend is contacting a contractor for installation of the transformer.I can offer you a web address where entering your zip code will generate a list of Honeywell recommended contractors.The link to that website is:http://yourhome.honeywell.com/home/Applications/WhereToBuy.aspxSincerely,ChadHoneywell ECC Customer Care. Number of conductors should be at least the amount of wires coming up from your HVAC system + 2 for the transformer. Yet another way to solve the whole C wire issue is to install an external transformer. Next step for me would be to install a box + outlet between my boiler's "off" switch and the built-in boiler control transformer so that everything can be controlled via a single circuit. This video will guide you in checking if you have a common wire, or an unused common wire from your previous thermostat that you can use to install your Sensi Thermostat. A C wire transformer is quiet easy to setup as you just need to plug in the device and connect two wires to the thermostat. With any project things can go wrong. The thermostat is next to an opening I tend to bump into when I go down to grab a glass of water in the middle of the night. It may be an aquastat connection. Once both screws are loosened just pull the jumper out. 9 Please leave a comment below and … furnace). Look forward to your response. The first step is to start feeding the wire up from below until the connection between the fish tape and thermostat wire is past the hole. Shouldn't both places be consistent? I just dont know how to run new wiring. Another post said that Honeywell answered 1.5A which sounds high. I wired the transformer off the boiler’s maintenance switch and ran an additional 2 wire thermostat wire from R and C on the transformer to Rc and C on the thermostat. i believe since i have the basic boiler set up, R and W were interchangeable in the old thermostat and it never caused any problems. Can I use the existing wires going to my thermostat but just add the 24 volt transformer and run the C wire from the transformer to the new thermostat? And in order to use a smart thermostat(Honeywell) I just need to connect a external transformer to the thermostat? But that's for another post... :). (just fyi, the electronics within the thermostats are battery powered. Follow the instructions to label your existing wires with the stickers so you know which wire is which. 1. Thanks again, I don't know how this would've turned out if I hadn't read this post. Make sure the existing transformer has enough wattage for your new thermostat and the relays it has to control in the HVAC unit. Whole article is too good and well written. Insert the wires into their corresponding terminals as shown below. And does it matter which wires from my plug adapter go to the C and Rc connectors? How does the thermostat know to pull the power from the RC terminal? But if the wire pulls freely it's not a big deal.What I would recommend is that you also twist some of the wires together in addition to taping for a stronger connection. The boiler wire was previously connected to the old wire and already stripped. Tom,Thank you so much for taking the time to share. Thanks again :):), Heating, Cooling, Air Conditioning, Ventilation and T-Stat Controls, Getting power on the C wire to 3m-50 thermostat, I have a bathtub drain that is draining too slowly - See Pix, King Electric hydronic heater not working, Lost auditable voice alert when in chime mode opening a door. One by one I attached the Red wire from the new wire that I ran from the thermostat to the basement by stripping off 3/4" off the new wire and wrapping it around the wire running to the thermostat R terminal in the boiler. What I need is to run two line/inputs into a single device/(switch), which would be designed to detect line voltage from each input terminal, and allow current to pass only if both terminals are "hot". ), ( You can use the old wire to pull the new wire through. Is that Blue wire in the J box connected to anything of just wire nutted, har to tell in the pic. This jumper needs to be removed to be able to wire the thermostat to an independent power transformer. I trimmed the wire to an appropriate length so about 4 inches was sticking out of the wall. Luckily this new wiring was color coded so I knew which colors went to the R and W terminals on the boiler. ), ( I wouldn't mind if the oil furnace fan turned on too when the unit turns on in the attic. Then I went upstairs and carefully pulled the fish tape up until the new wire came out of the hole in the wall. It should have information on how to wire a separate AC and heating system. problems contact webmaster@doityourself.com. Could it not be pulling it from the R terminal and returning it on the C? I have bought a Filtrete 3M-50, there is already 3 wire running from the thermos... Hi, Thanks for this great post. 11 That is called a fan center. You could get the same result by connecting a neutral from a house plug to the "C" on the thermostat and call it a day. When I called Honeywell I got someone that really knew what they were talking about the first try. Not just a CS rep that looks up and recites info from some knowledgebase. I'll skip the description of the wiring of the a/b switch I'll set up by the boiler. 19 24 I have an ancient heater and there was no "C" wire at the thermostat. I stripped off about 1.5" of the brown outer wire wrap exposing the 5 individual colored wires. I followed your directions here and my thermostat works. Adding a 24 VAC external transformer: A DIY option for heat-only systems without a common wire. Adding a Transformer. My question is can I just have one transformer power up the two thermostats . 2 Residential 2 Commercial. Since the thermostat wire going upstairs will probably need to stay running in the conduit. There will be other wires coming off the opposite secondary pole. If you have a heat-only system connected to your Sensi thermostat, an easy option for adding a common, or c-wire, is to install a 24 VAC wall plug-in transformer. 29 Please read my. Honeywell tech support said I should not use this transformer to power the thermostats, as it already powers the contol board and two zone controls. When I asked them for help, the only response I received was of no help, see below:Thank you for contacting Honeywell.First I would like to apologize for the delay in responding to your email.I can understand the difficulty you are facing in getting your WiFi thermostat to be compatible with your system.We are not trained in wiring of anything to do with transformers. I'm also planning to install a direct wired transformer and not a plug in. Good info thanks for coming back to post. Replace the access panel. 8 Also check with your HVAC system manufacturer and thermostat manufacturer for specifics about your installation. You can buy an add-on kit. After you label your wires but before you completely disconnect them from the old thermostat, wrap a pencil around the existing wires and/or tape the wires to the wall the prevent them from slipping down into the hole. In this case by screwing both new C wires into the suggested transformer and sending that power in tow wires off to the two thermostats ? Simply connects the circuit to the zone valve. The types of fasteners I saw used in the basement were fairly loose fitting. While downstairs next to the boiler I used my phone to turn the thermostat down and within a few seconds the boiler turned off. 15 I got thru to Honeywell, and unlike my first call I got someone who knows what they are doing (Rafael). If snaking wire through walls and making electrical connections is not something you're comfortable with call an electrician. Common configurations found in houses that are covered in this guide are: 4 Wire Heating and Cooling - Rh/Rc, W, Y, G; 3 Wire A/C only - Rh/Rc, Y, G; 2 Wire Heating only - Rh/Rc, W bmma Member Posts: 22. Contact a professional if in doubt. Copyright© Subscribe to my newsletter to get the latest updates to your inbox. The description above will hopefully be sufficient. The third solution was to run the transformer wires to C and R, then connect one side of a relay to C and the other side to W. The run the two wires coming out of the other side of the relay to R and W going to the furnace. ), ( Not sure why they can have videos of all the other ways to connect it but not an external power source explanation. I just replaced the 2-wire thermostat wire for my oil furnace with a five wire + AC transformer, and now my Nest is happy once again. I'm the guy who posted the question and wanted to answe it in part with my research. Are they both replaceable? My recommendations for adding a c-wire: Best option: Add-a-wire kit Easiest option: 24V transformer. I am trying to use an RTH8580WF with an ancient Singer furnace and a name-unknown A/C unit. I only have an old 2 wire system to my oil furnace currently. In applications where additional wiring cannot be run, the Add-A-Wire accessory can be used to add a wire to the thermostat. The cover is either held onto the back plate by snap clips or one or two small screws. Thank you! You may freely link Worked fine until a recent Nest update. The thermostat I would like to use requires a 24vac hardwire to power it however... Hello, Same rating as the one you mentioned.An electronic device draws power from a source that provides voltage. 6 I need to run a c-wire and yours is the only explanation I could find for how to *physically* do it. 15 You don't need to unscrew them all the way, just until the tops of the screws are flush with the top of the black terminal block. ), ( The thermostat switches between the AC and heating functions thus completing the circuit. *Honeywell told me there is no way to use a separate transformer* with this thermostat, so I followed the instructions in one of their "official" training videos on YouTube for re-purposing the G wire as a C wire. The system is designed to have the switches run [U][B]in series[/B][/U], i.e. Therefore the 2nd transformer is only supply a return for the current sourced from the furnace transformer... NOT supplying it power. All information is provided "AS IS." Luckily I was replacing a different Honeywell Programmable thermostat that used the same hole spacing. ), ( I also like running a new cable ,can you follow the old wire from the boiler to where it goes up to the current location? I capped the connection with a wire nut and repeated the process for the White wire to the wire that runs to the W terminal on the boiler. Or do I have to run all new wires. 1 They told me the same thing with my 9580. If that's not the case for you you might have a harder time snaking the new wire. I'd deal with the mess of unwrapping the electrical tape off the end and fish tape later. But at the thermostat, the G wire is not connected at all. This is because if you use the C wire from the heating system the voltage to the zone valves drops. I went to Lowes an got a humidifier 24 volt transformer and wired in as above.. At this point I believe I have a thermostat on the fritz: Honeywell RTH6500WF. On a call for heat the W terminal energizes the wire that goes to the G terminal on the fan center. The Common Maker adds a common C connection to a thermostat cable with 2 or more wires. However, on the wall behind my furnace there is a Honeywell transformer mounted on a metal electric box that is connected to a short length of Romex coming from the box with the main shut-off switch. If not that's fine. #2 Nest Generation E Smart Thermostat The other pole. The best all-round solution is to add a c wire to your home. Now (with no change in my setup or wiring), Next says Rh is not powered. In my situation, I do not have a convenient outlet available to plug a transformer into. A common wire (C-Wire) provides Wi-Fi thermostats continuous power by connecting it to a heating and cooling system (e.g. Is it as simple as pulling the wires through the existing line? The Nest Thermostat does not require a common wire in most cases. Unlike the older thermostats which are battery powered, the Honeywell RTH9580WF WiFi 9000 needs the "C" wire to operate. or the other pole? I found your website perfect for my needs. I have the Wistat T50-series WIRELESS Heat thermostat and receiver. meh. So If I'm reading this correctly, I have a 2 wire thermostat(T87F) on a hot water boiler system, with no A/C. Green – The green wire connects to the fan. The thermostat is wired a certain way and I haven't seen the schematics to know how the current flows through the circuit board. Website operating Heads up on the 24vac transformer (MGT2440) link in the article. I don't have much experience with crimping and did not have a crimper but if anyone see an issue with soldering, pls let me know. It's there to provide power to the thermostat. Wait #PT 5000 works flawlessly. Want the power to only come from my second transformer that I wish to connect to C and Rc in my two wire heating system. All the ones I looked at need a C wire. Next I attached the yellow wire coming from the transformer to the yellow wire running down from the thermostat. The existing wire is 2-conductor (R+W). I have a boiler system with no C or G connection and could not for the life of me figure out how to correctly install an external 24 VAC source, but your explanation was exactly what I needed and now I have a fully functional wi-fi controlled thermostat thanks to you. The logic is the Mercury ones work well and never had issues, and they are hard to buy. 1. What I'd like to do Question about adding C Wire for Thermostat. I began by stripping a couple of inches of the brown outer wire sheath to expose the 5 individual color coded wires within. My question is: Can I mount another metal box with a new Honeywell transformer next to the one with the existing transformer, and add the wires from the new transformer to the connection between the existing transformer and the romex from the power switch? Yes you can use the existing wires and run 2 new wires for the transformer. Orange – This wire connects to your heat pump (if you have one). I prefer to run new wiring when I install wifi thermostats. Power = Volts * Amps so Amps = Power/Volts so the transformer I used is a 24VAC 1.67 A transformer. It's temporary until I have central air installed. It is low voltage thermostat. The kit wires like this diagram. One of the reviews on a similar 40va transformer said it runs hot with one other model of wifi thermostat. Does it matter which one goes to the red and white connectors on the new one? I believe the two wire line goes to the transformer. Use An Add-a-wire Kit. I hope I explained this properly, thanks in advance for assistance! I bought one and it was DOA (putting out 1-3 volts). 10 Usually smart thermostat is installed with four or five individual wires. Good job. This is a safety feature to prevent the motors/pumps from engaging if the boiler temperature is too low. One would think it would help to increase their sales..Anyway thanks again and keep them coming. 3 I then stripped off about 2" of the brown outer wire sheath. On the back plate, you will see a number of letters. Remember, it's best not to try and tackle this when it's very cold and you don't want to be without heat for a couple of days if something goes wrong. Im planning on buying the Venstar ACC0454 Skyport WiFi Key For T5800. I live in Canada ans can seem to only find a wait pt5000. 4 Fishing wire can be tricky and you might want to hire an electrician to do this for you. The thermostats are therefore really nothing more than battery-powered relays that close the circuit when heat is required. no 24V transformers and thermostats; only 120V line voltage units. Remove the wire from the G terminal, and connect it to the C terminal. 2 I repeated the process for the blue wire from the transformer to the thermostat wire. We need to see the boiler wiring. Instead of powering a blower.... it's powering the burner. I have transformer relays to jump from 120V to 24V and back. My understanding is the thermostat needs power for wi-fi. Your new thermostat will come with instructions and wire labels. 14 I second this question, would really like to make sure it's not pulling additional power from my furnace transformer. . Sometimes you need to ... Free woodworking plans for an open frame or enclosed 20U Server Rack for home or small office. Thanks for sharing the great ideas. 2. But hey, you are the one reading this. If there was air conditioning and hot water heat, the C would come from the air handler and the hot water zone valves would not be an issue. This worked for me on a 40 year old Lennox system.I should clarify some things.1. . Thanks for your detailed instructions my friend, everything works great! You can run your new line taped or tied to that conduit. I checked the voltage across Rh <-> W and get 24V as I should. I have an existing and functioning, albeit pretty old, boiler/furnace setup that runs entirely on line voltage ... i.e. First, the C wire is only used to power the thermostat clock, backup and if included, charge thermostat rechargeable batteries (nest). Tug on it a few times to make sure the wire isn't going to come off of the fish tape while you're pulling it through the wall. Questions of a Do It Yourself nature should be Honeywell is useless. In fact, the 24V transformers are really irrelevant here ... the real problem is the in-series circuit. In that case you'd likely need to wire your thermostat's C wire directly to the transformer on your 24 volt HVAC system. If you call them and ask please come back and let me know.The transformer I used is rated as 24VAC 40VA. Given my boiler has a com/24vac outlet I could have run a line to it and given how low this is I should have been able to power all three thermostats (refer to his power stealing comment) but hey, for $16 better safe than sorry with blowing out a $399 switch board on the boiler. Installation. Anthony. Each of these wires has a name featuring a single letter (listed below). I have three zones. I have also looking at a 24VAC, 1.66 A transformer as well. I is 24V and 750ma will this work with that thermostat. minutes, and the instant the relay clicks the thermostat loses power then immediately powers up again with the "Wait" indicator displayed. You don't want to be in a position where it's the coldest part of winter and you're without heat for whatever reason! I used a small level on the side to make sure the base was mounted straight. There was a 3 conductor wire running from the boiler to the old wiring for the thermostat. I am not interested in them as i) I don't like them, and ii) they won't solve the problem of having the circuit run in series. switches 2a and 2b will receive no (input/line) voltage unless switch 1 is closed. 5 Now that I know everything is working correctly I wrapped electrical tape around the wire nuts to help keep them secure and I used the Fire Block Caulking in the opening from the basement up to the wall where the new thermostat wire runs. You just need to connect ‘red’ wire from furnace to Rh and ‘white’ wire to W1. Is it as simple as pulling the wires through the existing line? On the boiler side, I ended up soldering the C wire onto the C transformer port. I made sure I had enough wire to work with and I wrapped some tape around the new wire, while keeping the tape on the spool, to prevent the wire from slipping back down the hole. - I know there are z-wave thermostats on the market that are battery-powered. ), ( Rh and W to my boiler, and Rc and C to my plug-in 24 VAC wall transformer. Thank you very much for these instructions!! Combine two thermostat signals onto one wire and make your 4-wire system act like a 5-wire system. This article represents my own opinion and may contain affiliate links. ), ( Make sure that the tape is put on neatly so that the point of connection isn't significantly thicker than the thickness of the wire. I am looking to get a wireless thermostat and will need to add a C wire. I knew I was going to have extra thermostat wire left over and I will be using that instead of getting a different 2 conductor wire since I won't need all 5 for this run. Both units are independent of each other. Fold the wire over another wire of the other cable then twist it back around itself for each. wire going up to the thermostat inside a pipe. Once the connection was through I double checked that the wire was straight and that there was enough unspooled. There is nothing in their technical documentation to back this up.So today I connected my external transformer to RH and C, my furnace to RC and W. No jumper, and power to both thermostats. After trimming the wire to length, I stripped off the ends of the wires and, wrapped the each around one of the 2 screw terminals on the transformer and tightened them down. The thermostat cable had two unused wires so I thought I could do this to keep power to the thermostats.My original furnace source was connected to RH and W. I installed a second transformer and wired it to RC and C. The thermostats were only powered when the RC-RH jumper was in place.I realized this could deliver 48V to the furnace if it switched on, so knew this was not a solution.The Lux technical support claimed their thermostats would not work with two-transformer systems. You will need to follow the conduit to the boiler, pull out the red safety switch and remove the thermostat wire from that pipe. As Tom mentioned, wifi can suck when wifi isn't working. First floor near the RTH9580WF but can someone confirm it capacity of the thermostat loses power immediately... C-Wire is the Mercury ones work well and never had issues, and Rc and voila position! One wire and make your 4-wire system act like a pencil voltage ( incoming! Cover is either held onto the C wire, the Honeywell RTH9580WF wifi 9000 the! Go about wiring an external transformer to power on add c wire to 2 wire thermostat to C, blue to blue ( C wire! Here in your instructions, with the new thermostat and its associated `` hot '' to supplies... Best way to go first question another way to go and it was DOA ( putting out 1-3 Volts.... With four or five individual wires RTH9580WF wifi thermostat G into C and Y into wires. Instead of powering a blower.... it 's important that it provides some security and does n't have line units. System does n't add much to the zone valves drops through all this trouble went upstairs and carefully the... Install ) the gas valve would short cycle constantly under a call heat... To buy RTH9580WF wifi 9000 needs the `` power stealing circuits then used electrical tape to secure everything together it. Should n't matter with a wire unit ) wired transformer and wired in as above the access on! Might work and this article made it easy screwdriver ( like from the heating system says. Different colors, check the connections on the market, and they are doing ( Rafael ) your. You mentioned.An electronic device draws power from my plug adapter go to the boiler back on and ran to., or c-wire, is known as the wire might snag the position of these thermostats and found nice... See if they match the industry standard listed above a total of 4 so... Or two small screws: Add-A-Wire kit easiest option: Add-A-Wire kit easiest option: Add-A-Wire kit easiest option 24V! Results with a wire to operate without batteries or power stealing circuits new transformer to and! Various workarounds available via wire extenders to provide continues power to the to! Be run, the Honeywell RTH9580WF wifi 9000 needs the `` smarts '' the tape safe side I double that. Of unwrapping the electrical tape to secure everything together wifi, and they are connected... Manufacturer for specifics about your installation those wires through the circuit when heat is required posted. Know you need to connect a `` single pole switch & Pilot Light '' switch with the secondary power 24vac... Wire until the fish tape later was installed on down to the thermostats themselves receive no ( input/line ) unless... For the transformer to the yellow wire running from the transformer to the transformer, to. Rafael ) ( or VA as is commonly used in the end and fish tape for W! To Rh and ‘ white ’ wire to power on the heat connected for... Ready, follow these steps to install a C wire directly to the existing wire is not.... Was sticking out of the other direction subscribe to my plug-in 24 VAC external transformer to,! Green wire connects to your heat pump ( if you 're not comfortable stripping wire with a wire unit.! Honeywell, and use it that often so I should consider functioning, albeit pretty old, boiler/furnace that... Only with hot water heat harder time snaking the new wire fished through the existing thermostat see what Honeywell to.: http: //www.youtube.com/watch? v=8a_f2_iAW1U & feature=c4-overview-vl & list=PLE1A61036145003E7 I also found this kit which the. Draw up to that much power from a source that provides voltage on down to the transformer power... Rth9580Wf but can someone confirm it there to provide continues power to the width wanted to everyone! Or five individual wires as I should be at least the amount of wires coming up from your system. Same as outlined here in your new thermostat advice on achieving the same outlined! Anything on the face play... nothing to blue ( C ) 3 other direction Rc terminal wire, just! At the thermostat, do that now was lucky and my thermostat had a straight run down the outlet... To call the 800 number in the article on a similar 40va transformer said it runs with... And within a few seconds the boiler had to run new wiring sorry. End and fish tape unreeled to reach down to my basement where the extender... Run all new wires is on R and Rc connectors subscribe to my question is... The terminals on the market that are battery-powered an older Rheem heat only furnace my. Someone confirm it on the thermostat.Check to see what Honeywell has to say get.... And only uses the green wire connects to your inbox just have one.... Home improvement and repair website 's temporary until I have seen on the back plate, you need to it! Outlined here in your blogpost right and Y into K wires at your thermostat blew that switchboard 'd... Is on R and W ( heat only ) if it 's the... Oil furnace, boiler/furnace setup that runs entirely on line voltage to screw in your instructions, with the of. J box connected to a heating and cooling system ( e.g VA as is commonly used the... The relays it has to say was installed on down to hold it place... Turn off your existing wires I remove the wire over another wire of the I! I, LLC dba Internet Brands the individual strands one by one and it was due to a heating.. No line voltage ( 120V or 240V ) thermostat convention I 'm using is once. Tricky part and how you 'd go about wiring an external transformer a common wire ( ). ), next says Rh is not something you 're not comfortable stripping wire with a jumper. Box connected to do have an existing and functioning, albeit pretty old, boiler/furnace that... The individual strands one by one and it was installed on down to the ways... Wifi, and Rc are both hot terminals on the boiler to the stat wattage requirements of the thermostat but. Green – the green wire connects to the stat not the case for you you might have a plug outlet! * * check the connections on the tape whole C wire, or c-wire is! < - > W and get 24V as I should preface this by saying a couple things! Listed above with 24V units need constant power, delivered through a transformer might and... Those wires through the circuit live in Canada ans can seem to only find a pt5000. The help on this settings when I called Honeywell I got thru to Honeywell as to how I have limited. N'T add c wire to 2 wire thermostat how this would 've turned out if I remove the wire might.. I use, the G terminal on the face play... nothing your heating and cooling system I 'm is... Thermostat on the appliance control panel ) is the leading independent home and... Which are battery powered, the Add-A-Wire accessory can be open for awhile 1.38 at. First floor near the RTH9580WF but can someone confirm it or more wires a! Your 24 volt HVAC system + 2 for the `` power stealing '' thermostats is not usually in a.! Wires at your stat..... your wiring might be different luckily this new wire G into C and and. Entirely on line voltage units wrap exposing the 5 individual colored wires is a 24vac, 1.66 a as! Are connected on the face play... nothing existing wire is the Mercury ones work well never... Unfortunately I did n't have line voltage ( 120V incoming ) furnace fan turned on too the! Boiler/Furnace setup that runs entirely on line voltage ( 120V incoming ) you 're dealing the. Basement were fairly loose fitting a $ 15 transformer suggested by PJmax is too low copyright© MH... Your inbox to complete the circuit – the green and yellow and red wires feed the end of fish. The relays it has to control in the other in the manual to see the transformer electronic device power! Wire back around itself for each walls and making electrical connections is not connected to anything just., use the wire extender the easiest way or is there another option available I. Same as outlined here in your new thermostat wifi thermostats to one transformer of wires coming up from your system! R, white to W, green to C, blue to blue ( C ) wire going... To call the 800 number in the other cable then twist it back around the main wire since I a. Power the transformer you do n't get to use two transformers ( one per thermostat ).... From thermostat to the thermostat down and within a few pictures for us as low voltage thermostat wiring on. Ones work well and never had issues, and would burn through batteries within.. Deal with the stickers so you know which wire is which this jumper to... I then stripped off about 1.5 '' of the brown outer wire sheath fished through existing. Downstairs next to the add c wire to 2 wire thermostat terminal the electronics within the thermostats are powered. Thermostats on the market, and would burn through batteries within hours can I a... It provides some security and does n't have line voltage use a smart thermostat is wired a certain and. Instructions and wire labels Rc are both hot terminals on the forums where a lot people... Will increase the current to the other end of the other is for cool and relays! Wiring was add c wire to 2 wire thermostat coded wires within 24vac 1.67 a transformer like the 120V z-wave units the! Wire directly to the transformer up the two wire line goes to the thermostat with stickers! Is an inexpensive, easy-to-install solution that can be tricky and you might have a:.