Hi DIY Team!
I have a question about my new Emerson Smart Thermostat with my Electric Furrnace. I want to make sure of where these 2 wires of my old Thermostat would go. The old one uses mercury so I only have 2 wires but I managed to put a 3rd wire just in case for a future proof for a C Wire. Guess it's time to use it!
The new thermostat model is 1F87U-42WFC (link below) also my actual schema of the furnace (note the extra section in the middle are valves, one master that drives the 2nd one). The thermostat to be replaced would be the one in the bottom-right section of the schema.
If anyone could provide a litte detail, it would be helpful !
A quick guess is that I have to plug the extra C wire at the C terminal of the new thermostat then at the end other end (Furnace) I'll connect it to the 24v red end (current 24v). Then one of the 2 wire of the old thermostat to W|E and the other wire to RH. Do I have to find exactly which one of the 2 must go to W|E and RH ? I'm pretty sure yes, to provide the constant 24v to the thermostat (with C wire)
I recognize that schematic as I'm the one that colorized it.
I don't recognize what is shown to the right.
A wifi/smart thermostat requires an R, C and W connection.
Last edited by PJmax; 05-06-23 at 11:43 AM.
Reason: updated diagram
Hi!
Yes indeed it's schema you colorized it! A precious one to me! And of course I remember your name too! I was expecting a reply from you! The new installed furnace runs smooth and I thank you again. when I bought it from a second hand, all wires were disconnected. Without your explanations I wouldn't be able to do that by myself. Thank you again!
The 2 squares shown to the right are valves. The one with 5 blacks dots is the same as the one on the image below. The other square with colorized wires is also a valve, small one and they are interconnected. When I uninstalled the old furnace to install the new one I had to keep track of each wire and how to reconnect them. So I came up with this. Everything worked fine for the whole winter.
The thermostat to be replaced is the one inside the green box (basement). it has 2 wires but I do have a 3rd wire in the wall that is not connected to any end (not in thermostat and not in the furnace). When I see the schema and the thermostat inside the green box, (I might be wrong now) I would say that the left side wire would go to C of the new thermostat, the right side wire would go to RH of the new thermostat and then the extra wire that is not connected yet would go to W in the new thermostat and then to W of this schema! Because I think that the brown dot of the second valve is internally interconnected to the master valve that would provide the R.
That's a W/R 1311-102 zone valve. A real pain in the a** because it uses three wire switching.
It effectively has a common connection, one terminal to open and one terminal to close the valve.
So... you may not be able to do what you want.
That is a six terminal valve. I need you to label the terminals in the picture.
What is that other valve ? Four wires ?
I have just took pictures of both valves and model numbers. The main valve may look like the one I sent you but terminals are slightly different I'd say! The exact model number is 1361 rather than 1311 but it's pretty much the same. My model (1361-102) has 5 holes exactly and each one is illustrated on the main schema I sent at the original post.
The other one is a Motrotrol model number 672B307. its wire are colored in blue/black/white/brown and also that's what I reflected on the schema too. I'll try to label them but I think this would require for me to google for each valves and see exactly what terminal means.
I'll answer you as soon as possible.
Thank you again
PS: When you say I will not be able to achieve what I want, do you mean maybe the smart thermostat would not be compatible? (I do have a 3rd wire hanging on the wall not connected on both ends)
PSS: If also you could provide wiring explanation for a future smart thermostat for the first one (the one connected to the 3361, it would be nice But first is for my basement thermostat as the first floor is rented and it would be for a far future project for a replacement...
Updated my diagram.
672B valve = brown and blue - motor .... white and black - circ. switch
That 1361 valve is still a headache just like the other one.
Are you using the 1361 to turn on power to the 672B ?
The problem is that the Sensi would need a C in reference to R. The R to your thermostat is only active after the valve opens. You need continuous 24v on the R terminal. I'm thinking on how to do that but your setup is not ordinary.
With a typical zone valve.... like the 672B.... when you apply power to the motor the valve opens. When you remove power a spring closes the valve. With the 1361.... power is applied and the motor turns the valve open and stops. When power is applied again... the motor keeps turning and closes the valve. So 24v on valve terminal 4 is only there when valve is open. That's what your other valve is relying on to open.
Hi,
Sorry for the delay, been a very busy weekend.
I have double checked today the implementation, I have used a 16 way terminal to join all connections there. I made a schema reflecting that terminal on the bottom and double checked with the main simplified diagram that I sent at the beginning and it seems exact. So to answer the question of if I'm using the 1361 to turn on the power to the 672B I'd say probably yes! We can see on the main first simplified diagram that the R goes to 3 then probably internally from 1361, the 4 or 1 gives power to the 672B.
What if from this 16 way terminals, I'll just bring the R (T1) to the thermostat? but again remember that diagram where I boxed in green the thermostat I want to change. Because that's the 2 wires that I need to connect to the new thermostat (+ 1 additional wire not used yet for an R?)
You said earlier that my setup is not ordinary. Could it be another way? This setup is the original one before I removed the old furnace
Thank you again!
PS if you see that this new schema respect the main simplified one we can stick to that main schema. As you wish
Hi,
I was thinking of this but yeah, we lose the brown on 672b! There must some soft of combination. I tried to find onlnie the manual of the 672b but zero
I couldn't edit the last post, but this one isn't important, just I mis-colored the 2nd terminal where it goes to 3 of 1361, it was in blue but actually it's red.
Hi,
I wanted to post a quick update about someone's solution for Sensi, he came with this schema.
I asked why the W and C of the stat are actually the same on the schema. We can also see some slight changes like the black and blue connected to 3 of 1361 for a direct R. My setup is a Master/Slave one and we might need to break that up.
If you have time of course, you can let me know what you think.
Thank you as usual
Here is his explanation: Yes, they are the same, just used for different circumstances. The common from W closes the circuit to operate the valve motor, which is only a common on a call for heat. I've wired many zone valves in a way where the wire from the W terminal in the stat ultimately ends up back at the common at the transformer. This just completes the motor circuit. The smart stat needs a common outside of a call for heat to charge, but the common from W will not work when the stat is not calling for heat since the stat breaks that circuit under those conditions. Thats when the wire from the stats C terminal is used by the stat as a common for charging.If you look closer to the schematic to the left, the W circuit and C circuit both come off of the same size of the transformer already.
Ok...I haven't forgotten you. You have several wiring issues.
C = common (or negative) and W = switched 24v.
You can never join C and W or you'll get a direct short.
On the 672B..... you only need to use the motor lines.... blue and brown as there is no circ connection.
672B valve = brown and blue - motor .... white and black - circulator switch
You don't need the white and black switch wires.
You have R (24v) going to the blue terminal.
Then you have R from the stat going to brown terminal.
Valve will never open with 24v lines on it..... it needs common on one terminal.
Hi, I'm glad you haven't forgotten me. You are my only source of trust haha!
Yeah, I also wrote him saying like, I am confused because the R of stat once it get contact with W of the stat, W is R literally ... I told him, W is just a continuation of R and it has to go through the CP first to call for heat then at the other end of CP it falls to a common negative! I wouldn't have tried that setup anyway!!
Alright, then I'll try to come up with a schema for what you explained me and you confirm it for me please.
I might probably ask you a same question because I have another stat which is the RTH5100B1033 that I will connect it to the 1361 after summer. This stat doesn't need a C wire, it runs on batterie so you just have an R and W. I will also try to come up with a quick schema with that stat for the 1361.
Quick lesson on the W/R 1361 valve. (could never figure out why so complicated)
This is utilizing the basic 1361 diagram. I don't really understand the warp heater/switch setup.
Terminal 1 is C (common)
Terminals 2 and 5 are internally connected and are system R (24v)
Terminal 4 is technically W (switched 24v in by thermostat)
Terminal 3 becomes 24v out when valve is open. It can be used to power the 672B.
I'll modify this diagram and attach it to your heater and 672 valve.
I remember me and my dad read that schematic of the 1361 and he explained me a bit some basic things because on the pdf file there are some explanations but when you have to put it in work, we didn't want to take any risk. And also the terminal positions on this schematic are different than how I positioned them on my 1361, ex the 1 of this schema is C while on my main schematic is W. So that's why I never wanted to risk anything.
Hi,
If your schematic is strictly by valve numbering, would you confirm again that these numbering are the same as you provided me before? You can see it again on this schematic of mine (which is by position, newbie!)
By using your schematic, I ended up with this. As far as I understood, when you wrote "THERMOSTAT", this means that these RWC can be used for any thermostat (in my case two stats)? If so, then I feel like this setup is much more flexible, The first one, stats were kinda tied to the valves!
Also, I put the first stat that has only two wires on this schematic too. That wiring is still correct? It's the stat of the first floor and Sensi is for the basement. Later when I want to replace that stat with the RTH5100b, I just need to connect the R/W that's it?
So with this setup, whenever one of these 2 stats calls for heat, the respective valve would open too?
Oh!
The fact that I have 2 valves, I have 2 stats.
One is on the basement (Sensi Wifi that I want to install soon - should be tied to the 672b, this is the one that requires its C)
The other is on the first floor and has 2 wires (I would like to replace it much later with the RTH5100b1033 of Honeywell). This one (RTH5100b non smart) requires only R and W as it works on batterie. It should be tied to the 1361.
I missed my understanding
PS: you then confirm at least that the terminal numbering are the same as the 1361 you provided. On your very first reply you added the numbering it’s because they represent the ones on the official schematic of 1361
In the diagram.... the Sensi controls the 1361.
If you want the 1361 to be open to supply power to the 672B then the stat goes between 3 and the blue terminal. When the Sensi calls for heat.... the 672B will also open if that 672 stat is also calling.
If you want the 672B and its stat to be completely independent of the Sensi and the 1361... connect it to R and the blue terminal.
Ok.... slight problem.... if you have the 1361 supply the power to the 672B (3 to blue)..... the Sensi will start the boiler. If you want the 672B stat to be independent and start the boiler.... you will need a relay. As I mentioned you can't just tie the W's together or either stat will open both valves and start the boiler.
Umm I'm not sure I would be able to pick one solution or another. Because in my understanding or my situation is that the Sensi will be strictly used for the basement so I need to connect it with the 672b. When Sensi calls for heat, it must only open the valve of the 672b. This Sensi needs RWC
The 1361 is for the first floor and right now it has a simple stat with 2 wires (very old that uses mercury internally). This stat must control only the 1361. Later I would like to replace it with the Honeywell RTH5100b (https://www.honeywellstore.com/store...thermostat.htm)
For now, I'm trying to focus on the Sensi.
What kind of Relay I can use for my purpose? Cause when I hear relay, I might think of these Relays too. Not sure we are talking of the same relays. I do have a couple available from my old furnace that I removed.
I have been reading your last reply over and over again just to make sure I understood correctly. Sorry in advance for my misunderstand. Are these the 2 solutions you proposed? I want the Sensi to control only the 672b and the other stat (between 3 and soft blue or R and soft blue) would control only the 1361.
Please correct me if I'm wrong. Sorry for my misunderstand. If you can just give me one best solution for you for my situation I would be just more than happy..
Remember the simple stat between 3 and soft blue must control the 1361, I will replace it later with the Honeywell RTH5100b.
Hi,
Sorry for my last attempt, I can see already that both solutions I did were wrong as the primary stat wasn't connected at all to the 1361, probably my misunderstanding from your last message. I think we can continue from this now.
Here I'm showing again your explanation, This one is clear, and I made an attempt to connect the Sensi to the 672b but again we can see that I can't bring the W. Could I use the black and white for a W purpose that would connect to the missing W of Sensi then goes to T2 ?
Also, the 3 of 1361 to blue of 672b is an R to power the 672b. Is that R conditioned or always a continuous R, can't we just bring a continuous R to 627b?
I wish I could find any schematic explanation of the 672b like you did the explanation of the 1361. Normally, you have 24v R to the motor (blue) and 24v C (Brown) back to the transformer, then between, you plug the stat (Sensi) to do the On/Off! (White/Black?)
Sincerely!
Your previous schematic
This attempt is with your schematic + the Sensi to 672b (still missing the W)
This attempt is with my original schematic (By terminal positions) (sorry I couldn't upload it so I've upload it on Postimg).
Not sure if we have closed the thread. I wasn't sure about the final decision. After some researches, someone suggested me this schematic but also suggested to change the transformer from 40VA to at least 75VA to be sufficient.
Your last diagram will work. Either valve supplies the W independently.
The internal transformer is 40va and should be ok for the load.
It would not hurt to replace it with a 75va unit.
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05-04-23, 11:57 AM
The new installed furnace runs smooth and I thank you again. when I bought it from a second hand, all wires were disconnected. Without your explanations I wouldn't be able to do that by myself. Thank you again!
The new installed furnace runs smooth and I thank you again. when I bought it from a second hand, all wires were disconnected. Without your explanations I wouldn't be able to do that by myself. Thank you again!
