# Wyze Thermostat on 2 wire system **URL:** \ **Category:** Tips & Tricks\ **Tags:** thermostat\ **Created:** [December 30, 2020, 2:58am UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072 "2020-12-30T02:58:43Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![speadie](https://sea2.discourse-cdn.com/wyze/user_avatar/forums.wyze.com/speadie/32/106541_2.png) [@speadie](https://forums.wyze.com/u/speadie)\ **Post date:** [January 9, 2021, 6:58pm UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/21 "2021-01-09T18:58:48Z")
This will kill your furnace. You are backfeeding it power from the external transformer. One of those 2 wires in your thermostat already carries 24V from the furnace to the thermostat. There is no case in which a thermostat should feed power from a wall wart back into the furnace. You will damage something. How was your old thermostat hooked up? It’s literally not possible for there to be 2 wires going to a thermostat and have one control the fan and one control something else. That’s not how thermostats work. Thermostats are just fancy switches. They connect 2 or more points together. ---
**Author:** ![keegancdr](https://avatars.discourse-cdn.com/v4/letter/k/22d042/32.png) [@keegancdr](https://forums.wyze.com/u/keegancdr)\ **Post date:** [January 9, 2021, 7:20pm UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/22 "2021-01-09T19:20:34Z")
Sounds like maybe the wires are connected incorrectly at the furnace? So maybe that’s why this combo actually works for you ---
**Author:** ![kjk0355](https://avatars.discourse-cdn.com/v4/letter/k/9dc877/32.png) [@kjk0355](https://forums.wyze.com/u/kjk0355)\ **Post date:** [January 10, 2021, 2:55am UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/23 "2021-01-10T02:55:23Z")
My trans went to c and rc, control wires in my case w and g ---
**Author:** ![djbigkev](https://avatars.discourse-cdn.com/v4/letter/d/e8c25b/32.png) [@djbigkev](https://forums.wyze.com/u/djbigkev)\ **Post date:** [January 10, 2021, 4:44pm UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/24 "2021-01-10T16:44:45Z")
I to had a two wire system. But I wired the separately purchase wall 24Vplug transformer to RC & C and the two wires from the furnace to Rh W1. Works great! I also had an issue when trying to walk through the set up. It kept telling me I had it incorrectly wired. I believe this is a glitch that will need to be looked at by Wyze. once you get past this the unit works well Good luck Kevin ---
**Author:** ![robertcouto](https://avatars.discourse-cdn.com/v4/letter/r/c68b51/32.png) [@robertcouto](https://forums.wyze.com/u/robertcouto)\ **Post date:** [January 10, 2021, 4:58pm UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/25 "2021-01-10T16:58:36Z")
I totally agree about a possible glitch. I did one thermostat and it agreed with the wiring and went seamless. The second thermostat I did the same way yet it kept saying in the app that the wiring was incorrect so I just bypassed it and continued. Both thermostats are working perfect !!! ---
**Author:** ![kjk0355](https://avatars.discourse-cdn.com/v4/letter/k/9dc877/32.png) [@kjk0355](https://forums.wyze.com/u/kjk0355)\ **Post date:** [January 10, 2021, 5:14pm UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/26 "2021-01-10T17:14:16Z")
I switched it as you recommended and that works fine also. I only had to change one wire from the g to rh, both worked ---
**Author:** ![kjk0355](https://avatars.discourse-cdn.com/v4/letter/k/9dc877/32.png) [@kjk0355](https://forums.wyze.com/u/kjk0355)\ **Post date:** [January 10, 2021, 5:17pm UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/27 "2021-01-10T17:17:28Z")
I moved my g wire to the rh and that works also I still don’t understand why rc is even in the equation that’s supposed to be for a cooling system ---
**Author:** ![speadie](https://sea2.discourse-cdn.com/wyze/user_avatar/forums.wyze.com/speadie/32/106541_2.png) [@speadie](https://forums.wyze.com/u/speadie)\ **Post date:** [January 10, 2021, 8:27pm UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/28 "2021-01-10T20:27:29Z")
Rc and C power the thermostat. If you tell the wyze that you have Rc, C, Rh, and W, it will get power from Rc and C and make contact between Rh and W when heat is called for. ---
**Author:** ![kjk0355](https://avatars.discourse-cdn.com/v4/letter/k/9dc877/32.png) [@kjk0355](https://forums.wyze.com/u/kjk0355)\ **Post date:** [January 11, 2021, 4:22pm UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/29 "2021-01-11T16:22:57Z")
I just wired another one on a two wire system for my son-in-law, furnace to RH and W and transformer to c and Rc, works fine. Wyze app did tell me it was wrong, just by passed it in the app Kevin ---
**Author:** ![DesertGecko](https://avatars.discourse-cdn.com/v4/letter/d/f07891/32.png) [@DesertGecko](https://forums.wyze.com/u/DesertGecko)\ **Post date:** [January 26, 2021, 4:48am UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/30 "2021-01-26T04:48:49Z")
Having read this entire thread, I’d say it seems the consensus is those of us with a 2-wire system without the ability to use the Wyze C-wire adapter, simply need to supply power for the thermostat to run. Agreed? I’m replacing a modern programmable digital dumb thermostat that uses batteries _ **or** _ an optional C-wire. Otherwise, it accepts my W and R wires without complaint. My old Coleman oil burner was installed before the world even knew what a PCB was. For those who still don’t know, a PCB is a printed circuit board. My troublemaking low back willing, tomorrow I’m gonna run a wire pair from my 24v doorbell transformer to power my Wyze tstat and save myself $25. Has anyone else done this? 24v is 24v, at least regarding these lil bitty transformers. Should work like a charm. Well, or a chime. 🤣 I’ll report back if I survive a trip up to the attic. ---
**Author:** ![speadie](https://sea2.discourse-cdn.com/wyze/user_avatar/forums.wyze.com/speadie/32/106541_2.png) [@speadie](https://forums.wyze.com/u/speadie)\ **Post date:** [January 27, 2021, 1:11am UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/31 "2021-01-27T01:11:04Z")
As long as the doorbell transformer can provide enough power it should work, but be aware that a lot of doorbell transformers are actually 8 or 16 volts. ---
**Author:** ![DesertGecko](https://avatars.discourse-cdn.com/v4/letter/d/f07891/32.png) [@DesertGecko](https://forums.wyze.com/u/DesertGecko)\ **Post date:** [January 29, 2021, 1:31am UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/32 "2021-01-29T01:31:55Z")
I haven’t looked at it yet. I have to climb the attic stairs and then navigate an obstacle course that many a boot camp Marine would fail, to get to where I think the transformer might be. I have a serious condition with the nerves in my lower back causing my legs to go out on me at the most inopportune times, so I must be careful. I’m pretty sure the transformer is 24v. All I’ve ever seen around these parts are 24v, and tbh I didn’t know there were other voltages for doorbells. I also have a nominally 29.4v hoverboard charger I thought about trying, or at least checking the true output. I bet it’s closer to 24v. Any steady supply of around 24v that will supply half an Amp should work. ---
**Author:** ![JasonF](https://avatars.discourse-cdn.com/v4/letter/j/f14d63/32.png) [@JasonF](https://forums.wyze.com/u/JasonF)\ **Post date:** [February 7, 2021, 1:54am UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/33 "2021-02-07T01:54:46Z")
I have a two wire heat only system. I was able to make this work with 3 total wires to the thermostat. Note: I do have spare wires to use that run down to my furnace already. Being that 24vac already runs to the thermostat location, there should be no need to incorporate a second 24vac power supply. For each thermostat, I tied one spare (black) wire onto the opposite terminal of the transformer than the white wire. (This is the same terminal that goes directly to my zone valves from the transformer) Here is my diagram on how I wired it with no issues. ![20210206_143650](https://us1.discourse-cdn.com/wyze/original/3X/2/2/22256960334130fdf3b68c551e9a5c3076ac3550.jpeg) ---
**Author:** ![csProf](https://sea2.discourse-cdn.com/wyze/user_avatar/forums.wyze.com/csprof/32/42746_2.png) [@csProf](https://forums.wyze.com/u/csProf)\ **Post date:** [February 9, 2021, 7:53pm UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/34 "2021-02-09T19:53:47Z")
I have a 2-wire heating system with red and white wires to primitive thermostat. Some thermostats in the house have an extra wire that is unused at either the furnace or the thermostat end. In other cases, I can pull a third wire. Red wire from thermostat is connected directly to one side of transformer and white through the zone valve to the transformer. It would seem I would connect extra wire to white side of transformer and at the thermostat connect the extra wire to rc, red wire to both C and Rh and white wire to W1. Will that work? Ken ---
**Author:** ![speadie](https://sea2.discourse-cdn.com/wyze/user_avatar/forums.wyze.com/speadie/32/106541_2.png) [@speadie](https://forums.wyze.com/u/speadie)\ **Post date:** [February 10, 2021, 12:28am UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/35 "2021-02-10T00:28:56Z")
Connect the spare wire to C and the common side of the transformer, the red wire goes to Rc and the white wire to W1. This will only work if you have enough current handling capacity in the transformer to power the wyze and the zone valve at the same time- if it doesn’t work, or you get relay chatter, you would need a separate transformer to power the thermostat, or a zone system that supports powered thermostats. ![image](https://us1.discourse-cdn.com/wyze/original/3X/1/c/1cac6259def433e4348f01095ce9b532251856cc.png) ---
**Author:** ![csProf](https://sea2.discourse-cdn.com/wyze/user_avatar/forums.wyze.com/csprof/32/42746_2.png) [@csProf](https://forums.wyze.com/u/csProf)\ **Post date:** [February 10, 2021, 1:29am UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/36 "2021-02-10T01:29:38Z")
Thanks a bunch. Actually, similar solution as I had because “c” accomplishes the attaching red to two places. There are 5 separate transformers on my system but Taco zones have a big draw. I assume “relay flutter” is in the thermostat. What’s best wiring (I’ve seen more than one) when using separate transformer? Thanks again for your help! Skc ---
**Author:** ![speadie](https://sea2.discourse-cdn.com/wyze/user_avatar/forums.wyze.com/speadie/32/106541_2.png) [@speadie](https://forums.wyze.com/u/speadie)\ **Post date:** [February 10, 2021, 2:34am UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/37 "2021-02-10T02:34:25Z")
With a separate transformer in the same room as the valves, you either need 4 wires, or a relay and 3 wires. second transformer + 4 wires+ zone valve: ![image](https://us1.discourse-cdn.com/wyze/original/3X/9/8/98fcf9b11c397c342a94c613ddcfff53649ec98f.png) second transformer + 24 VAC NO Relay + 3 wires + zone valve: ![image](https://us1.discourse-cdn.com/wyze/original/3X/0/e/0e1d96ce91b59bdf73094f7d3f67649ba024712e.png) With a separate transformer at each thermostat, you’d only need 2 wires, but then you have a wire running to each of the thermostats to a wall mounted transformer. The diagram would look like this: ![image](https://us1.discourse-cdn.com/wyze/original/3X/b/a/ba536272923cc6ce4eba2639ce1c9ed0f12f5a6f.png) ---
**Author:** ![csProf](https://sea2.discourse-cdn.com/wyze/user_avatar/forums.wyze.com/csprof/32/42746_2.png) [@csProf](https://forums.wyze.com/u/csProf)\ **Post date:** [February 10, 2021, 2:58am UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/38 "2021-02-10T02:58:50Z")
Nifty diagram. That’s the one that sounded right as I looked throUgh the thread. Thanks for your time. CSprof ---
**Author:** ![csProf](https://sea2.discourse-cdn.com/wyze/user_avatar/forums.wyze.com/csprof/32/42746_2.png) [@csProf](https://forums.wyze.com/u/csProf)\ **Post date:** [February 10, 2021, 10:33pm UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/39 "2021-02-10T22:33:34Z")
Have new problem. Phone sees Bluetooth on thermostat and show connected. The WYZE app then just spins and spins at “Select your network. Phones connect fine to WiFi. Tried IPCONFIG /RENEW without help. Have you seen this before? Or does it take a long time? Ken ---
**Author:** ![speadie](https://sea2.discourse-cdn.com/wyze/user_avatar/forums.wyze.com/speadie/32/106541_2.png) [@speadie](https://forums.wyze.com/u/speadie)\ **Post date:** [February 11, 2021, 12:53am UTC](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072/40 "2021-02-11T00:53:01Z")
Not sure about wifi connection issues. it took a few seconds for me and then connected, but I’ve got multiple access points spread throughout my house. [Previous page](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072.md?page=1) [Next page](https://forums.wyze.com/t/wyze-thermostat-on-2-wire-system/152072.md?page=3)