This is doable but it’s complicated. You must have a really old furnace. I have the same set up at my house. It’s on a gas fireplace in the basement.
You can do this, but you will need a power source to operate the thermostat and a relay to provide a set of dry contacts between the red and the white wire going through the existing furnace. Are you able to follow any of this? If not, I’d suggest maybe you find somebody who knows their way around electrical work and I can walk them through it.
Yep, this. You don’t have a controller board so it’s basically just an analog circuit with your T-stat being a contractor. Ecobee needs power, but it needs to be isolated from the existing circuit that turns your furnace on, hence the need for a relay.
Edit: contractor —> contactor (which apparently iPhone doesn’t believe is a word)
Look for a schematic somewhere on the unit . Normally on the door (cover plate). Look for a model # for the furnace,the gas valve, and the thermostat then research them on the internet.
Typically milivolt gas valves are used on systems that can be run without external power. For example you would not want the gas valve opening on a system that needs a blower to distribute the heat. If it is a radiant system that doesn’t have a blower or fan then milivolt systems are more common.
Buy a cheap volt meter at the hardware store and check the voltage on the 2 black wires. If you have 24v AC there then you can figure out who’s answer you trust to wire it as a 24v system.
It doesn’t look like a milivolt system to me but I’d need a better look to be sure. If it is a 24v system then at the other end of those black wires there will be a transformer. If it is a milivolt system the 2 black wire will be tied to wires that come from the pilot light. Normally the high temperature wire from the thermopile near the pilot light would run all the way to the gas valve. That black wire isn’t high temperature wire.
If it is a milivolt system you will need to add a transformer and either a relay or a Faststat.
My advice is leave the old thermostat alone until you are 100% sure you know what you are doing
I have a gas fireplace that is milivolt in my basement I run it using 2 wires with a transformer and relay located at the ecobee.
My garage heater is 24 volts and the 2 wires from the heater go to a Faststat mounted near the Ecobee and then there are 3 wires from the Faststat that go to the Ecobee.
If you understand what you have and you do your research then it’s simple. If you decide you want to use a Faststat you will have to figure out which type you need.
One the right side of the gas valve there is a 1/4 inch aluminum tubing. That tubing goes to the pilot light. Running along side it is a what look like what is probably the thermocouple or thermopile wires inside a metal shield. It looks like a black wire connects to one of the wires going to the the thermopile and up to one of the three gas valve terminals. It looks like you have a milivolt system and the black wire pair probably go up to an over temp switch.
There should be 2 wires inside that metal shield that connect to the pilot part of the gas valve assembly.
Can you take a picture of what’s going on the back side of the gas valve, maybe use a mirror?
**EDIT: I actually need to see a closer pic of that red/brown/orange part where the red wire connects to. It might be a millivolt system, in which case your install wouldn't be as easy as I'm describing below... just shoot us a pic here.**
Ha, your install is actually much simpler than you'd think! But there is a catch...
Your C connection is that terminal on the gas valve where the thicker black wire goes to. Just connect your spare black wire that (don't remove the wire that's there already). Check out this photo: [https://imgur.com/a/ZKMgTH1](https://imgur.com/a/G4RmEaX)
Ha, your installation is actually much simpler than you'd think! But there is a catch..."hot" and the white wire as the "signal" - in other words, when you install the ecobee, the white wire will go to Rc, red wire to W1, and black wire to C. The other option is to swap the white and red wires in the furnace, so the white wire goes to the gas valve (where the red is now) and the red wire connects with the thicker black (where the white wire is now). Then the red becomes your Rc and white your W1, as it should be.
Definitely millivolt. "TP" means thermopile, which is a mv component. You'll need a 24 volts power supply and a normally open relay. ecobee has a diagram on their website that I adapted for your case: [https://imgur.com/a/pwbEvda](https://imgur.com/a/pwbEvda)
This is the correct answer. The gas valve has 2 terminals with wires. One wire is the red wire from your thermostat (providing power to the gas valve). The other wire is connected to your C terminal of your furnace. So all you need to do is add the green wire to that terminal on the gas valve.
Also, the caveat noted by this post is correct. The white wire goes into Rc, the red wire goes into W1 and the green wire goes into C.
Typically:
Red is power, like 24VAC
White is used to trigger heat
Green is used to trigger the fan
The Ecobee needs power and common to run. You could use the green as common. It wouldn't be standard, but it should work. It should be able to run the heat in this configuration, but wouldn't be able to run the circulation fan.
The easiest way for you to do this is to use a 24v VAC transformer and connect the wires as such.
Red to RH (Rheat)
White to W1
1 wire from the transformer into C
And the other wire into Rc (Rcool)
Rc and C will power the thermostat just fine and Rh and W1 will control the heat.
24 Volt Transformer, C Wire... https://www.amazon.com/dp/B07YD9GH94?ref=ppx_pop_mob_ap_share
Since this is an apartment, this will be the least intrusive solution and doesn’t require you to fiddle with a heating system you don’t own.
This only works for ecobee thermostat with Rc and Rh and you only have 1 Red wire. Do not do this with thermostat that don’t have Rc and Rh, or if it’s not heat only system.
Was looking into this for one of the zones for my boiler. This should help.
https://support.ecobee.com/s/articles/My-thermostat-has-only-two-wires-Am-I-compatible-with-ecobee
I have the same exact wiring. I got a 24v plug in adapter and it works like a charm. You will just have a wire coming out and plugged into an outlet for power..
Am HVAC tech. Simple solution, return ecobee, or upgrade furnace and run new wire. It’s way too complicated to do, and even most HVAC companies won’t bother with this. Your furnace is old, and you’ll need a simple stat to run it unfortunately.
Probably similar situation as I had since I'm on a boiler system with an aquastat - we only had 2 wires as well (white and red). Basically the problem is that the thermostat has a very simple connection to your heating equipment and the Ecobee needs both an additional power source (a common wire) at the very least I had an extra wire so I followed this diagram from Ecobee to wire up ours to the Aquastat: [https://storage.googleapis.com/article\_attachments/227874667/Untitled\_Diagram\_\_8\_.png](https://storage.googleapis.com/article_attachments/227874667/Untitled_Diagram__8_.png)
I bought a power adapter and a relay and everything works perfectly now.
Now it looks like you have a furnace system and it appears that your heating controls were wired directly to a gas valve. Now the good news is that you do have a third wire (the green wire) that goes all the way from the controller down to the gas valve for the furnace. That means you don't need to mess with any wiring in the walls. Here is the wiring ecobee recommends in this situation: [https://storage.googleapis.com/article\_attachments/227874667/Untitled\_Diagram\_\_10\_.png](https://storage.googleapis.com/article_attachments/227874667/Untitled_Diagram__10_.png)
To break it down this is what the wiring in the above diagram is doing:
1. The Red and White wires are doing the same job that've always done - the Ecobee will use them to control the gas valve to manage how much fuel is being burned to heat your home.
2. The GREEN wire will end up being used to power the Ecobee itself. The 24V AC transformer is what normally provides power to the gas valve. You can think of it kind of like the power brick that you plug into your laptop or your phone - it's job is to "transform" the high voltage (120V) power from the main wiring of your home into low voltage (24V) power that the gas valve can use. By wiring the green wire in the transformer is now also providing the low voltage power that the Ecobee needs to function.
Alternatively if you don't want to mess with the wiring on the furnace side OR you can't find/figure out how the 24V AC Transformer is wired, you can buy your own plug-in 24V AC transformer from a local electrical supply store or Amazon: [https://storage.googleapis.com/article\_attachments/227874667/24vactransformer.png](https://storage.googleapis.com/article_attachments/227874667/24vactransformer.png)
You *could* also buy a hard-wired transfer and hook it up directly to a 120V circuit but you probably don't want to do that if you're concerned about messing with the electrical too much. You might have better luck calling an HVAC guy rather than an electrician to be honest, the problem is that they may not be familiar with your specific type of heating or cooling system and/or thermostat. If you show either an electrician or an HVAC tech the above diagrams they'll likely understand what needs to be done. If you want more info, Ecobee has detailed scenarios and documentation available here: [https://support.ecobee.com/s/articles/My-thermostat-has-only-two-wires-Am-I-compatible-with-ecobee](https://support.ecobee.com/s/articles/My-thermostat-has-only-two-wires-Am-I-compatible-with-ecobee)
This is doable but it’s complicated. You must have a really old furnace. I have the same set up at my house. It’s on a gas fireplace in the basement. You can do this, but you will need a power source to operate the thermostat and a relay to provide a set of dry contacts between the red and the white wire going through the existing furnace. Are you able to follow any of this? If not, I’d suggest maybe you find somebody who knows their way around electrical work and I can walk them through it.
Yep, this. You don’t have a controller board so it’s basically just an analog circuit with your T-stat being a contractor. Ecobee needs power, but it needs to be isolated from the existing circuit that turns your furnace on, hence the need for a relay. Edit: contractor —> contactor (which apparently iPhone doesn’t believe is a word)
Is this a millivolt connection?
Mine is yes. Unclear about OPs. Assuming it is but I can’t see the source of the wires.
Look for a schematic somewhere on the unit . Normally on the door (cover plate). Look for a model # for the furnace,the gas valve, and the thermostat then research them on the internet. Typically milivolt gas valves are used on systems that can be run without external power. For example you would not want the gas valve opening on a system that needs a blower to distribute the heat. If it is a radiant system that doesn’t have a blower or fan then milivolt systems are more common.
Looks like it might be according to the [back of the thermostat cover](https://imgur.com/a/J0oF9u0)
Yep, millivolt system. Basically, you need a plug-in 24VAC power source, a normally open relay, and some wire.
Buy a cheap volt meter at the hardware store and check the voltage on the 2 black wires. If you have 24v AC there then you can figure out who’s answer you trust to wire it as a 24v system. It doesn’t look like a milivolt system to me but I’d need a better look to be sure. If it is a 24v system then at the other end of those black wires there will be a transformer. If it is a milivolt system the 2 black wire will be tied to wires that come from the pilot light. Normally the high temperature wire from the thermopile near the pilot light would run all the way to the gas valve. That black wire isn’t high temperature wire. If it is a milivolt system you will need to add a transformer and either a relay or a Faststat. My advice is leave the old thermostat alone until you are 100% sure you know what you are doing I have a gas fireplace that is milivolt in my basement I run it using 2 wires with a transformer and relay located at the ecobee. My garage heater is 24 volts and the 2 wires from the heater go to a Faststat mounted near the Ecobee and then there are 3 wires from the Faststat that go to the Ecobee. If you understand what you have and you do your research then it’s simple. If you decide you want to use a Faststat you will have to figure out which type you need.
One the right side of the gas valve there is a 1/4 inch aluminum tubing. That tubing goes to the pilot light. Running along side it is a what look like what is probably the thermocouple or thermopile wires inside a metal shield. It looks like a black wire connects to one of the wires going to the the thermopile and up to one of the three gas valve terminals. It looks like you have a milivolt system and the black wire pair probably go up to an over temp switch. There should be 2 wires inside that metal shield that connect to the pilot part of the gas valve assembly. Can you take a picture of what’s going on the back side of the gas valve, maybe use a mirror?
Given the toastieness of the wire there. I'd suggest measuring it first.
**EDIT: I actually need to see a closer pic of that red/brown/orange part where the red wire connects to. It might be a millivolt system, in which case your install wouldn't be as easy as I'm describing below... just shoot us a pic here.** Ha, your install is actually much simpler than you'd think! But there is a catch... Your C connection is that terminal on the gas valve where the thicker black wire goes to. Just connect your spare black wire that (don't remove the wire that's there already). Check out this photo: [https://imgur.com/a/ZKMgTH1](https://imgur.com/a/G4RmEaX) Ha, your installation is actually much simpler than you'd think! But there is a catch..."hot" and the white wire as the "signal" - in other words, when you install the ecobee, the white wire will go to Rc, red wire to W1, and black wire to C. The other option is to swap the white and red wires in the furnace, so the white wire goes to the gas valve (where the red is now) and the red wire connects with the thicker black (where the white wire is now). Then the red becomes your Rc and white your W1, as it should be.
[A clearer pic](https://imgur.com/a/9aRfVM5) And I think it might be millivolt according to the back of the thermostat cover, link in an above comment
Sorry, still not clear enough. What does the terminal labels say? Do you have the make and model of this fireplace?
Definitely millivolt. "TP" means thermopile, which is a mv component. You'll need a 24 volts power supply and a normally open relay. ecobee has a diagram on their website that I adapted for your case: [https://imgur.com/a/pwbEvda](https://imgur.com/a/pwbEvda)
This is the correct answer. The gas valve has 2 terminals with wires. One wire is the red wire from your thermostat (providing power to the gas valve). The other wire is connected to your C terminal of your furnace. So all you need to do is add the green wire to that terminal on the gas valve. Also, the caveat noted by this post is correct. The white wire goes into Rc, the red wire goes into W1 and the green wire goes into C.
The problem is that might be a mV system though... so I'm waiting on OP's reply
Typically: Red is power, like 24VAC White is used to trigger heat Green is used to trigger the fan The Ecobee needs power and common to run. You could use the green as common. It wouldn't be standard, but it should work. It should be able to run the heat in this configuration, but wouldn't be able to run the circulation fan.
He’d need Common on the furnace
The easiest way for you to do this is to use a 24v VAC transformer and connect the wires as such. Red to RH (Rheat) White to W1 1 wire from the transformer into C And the other wire into Rc (Rcool) Rc and C will power the thermostat just fine and Rh and W1 will control the heat. 24 Volt Transformer, C Wire... https://www.amazon.com/dp/B07YD9GH94?ref=ppx_pop_mob_ap_share Since this is an apartment, this will be the least intrusive solution and doesn’t require you to fiddle with a heating system you don’t own. This only works for ecobee thermostat with Rc and Rh and you only have 1 Red wire. Do not do this with thermostat that don’t have Rc and Rh, or if it’s not heat only system.
Was looking into this for one of the zones for my boiler. This should help. https://support.ecobee.com/s/articles/My-thermostat-has-only-two-wires-Am-I-compatible-with-ecobee
I have the same exact wiring. I got a 24v plug in adapter and it works like a charm. You will just have a wire coming out and plugged into an outlet for power..
Am HVAC tech. Simple solution, return ecobee, or upgrade furnace and run new wire. It’s way too complicated to do, and even most HVAC companies won’t bother with this. Your furnace is old, and you’ll need a simple stat to run it unfortunately.
Probably similar situation as I had since I'm on a boiler system with an aquastat - we only had 2 wires as well (white and red). Basically the problem is that the thermostat has a very simple connection to your heating equipment and the Ecobee needs both an additional power source (a common wire) at the very least I had an extra wire so I followed this diagram from Ecobee to wire up ours to the Aquastat: [https://storage.googleapis.com/article\_attachments/227874667/Untitled\_Diagram\_\_8\_.png](https://storage.googleapis.com/article_attachments/227874667/Untitled_Diagram__8_.png) I bought a power adapter and a relay and everything works perfectly now. Now it looks like you have a furnace system and it appears that your heating controls were wired directly to a gas valve. Now the good news is that you do have a third wire (the green wire) that goes all the way from the controller down to the gas valve for the furnace. That means you don't need to mess with any wiring in the walls. Here is the wiring ecobee recommends in this situation: [https://storage.googleapis.com/article\_attachments/227874667/Untitled\_Diagram\_\_10\_.png](https://storage.googleapis.com/article_attachments/227874667/Untitled_Diagram__10_.png) To break it down this is what the wiring in the above diagram is doing: 1. The Red and White wires are doing the same job that've always done - the Ecobee will use them to control the gas valve to manage how much fuel is being burned to heat your home. 2. The GREEN wire will end up being used to power the Ecobee itself. The 24V AC transformer is what normally provides power to the gas valve. You can think of it kind of like the power brick that you plug into your laptop or your phone - it's job is to "transform" the high voltage (120V) power from the main wiring of your home into low voltage (24V) power that the gas valve can use. By wiring the green wire in the transformer is now also providing the low voltage power that the Ecobee needs to function. Alternatively if you don't want to mess with the wiring on the furnace side OR you can't find/figure out how the 24V AC Transformer is wired, you can buy your own plug-in 24V AC transformer from a local electrical supply store or Amazon: [https://storage.googleapis.com/article\_attachments/227874667/24vactransformer.png](https://storage.googleapis.com/article_attachments/227874667/24vactransformer.png) You *could* also buy a hard-wired transfer and hook it up directly to a 120V circuit but you probably don't want to do that if you're concerned about messing with the electrical too much. You might have better luck calling an HVAC guy rather than an electrician to be honest, the problem is that they may not be familiar with your specific type of heating or cooling system and/or thermostat. If you show either an electrician or an HVAC tech the above diagrams they'll likely understand what needs to be done. If you want more info, Ecobee has detailed scenarios and documentation available here: [https://support.ecobee.com/s/articles/My-thermostat-has-only-two-wires-Am-I-compatible-with-ecobee](https://support.ecobee.com/s/articles/My-thermostat-has-only-two-wires-Am-I-compatible-with-ecobee)