Upgrading Heat Only Thermostat to Wifi

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Old 12-02-20, 01:31 PM
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Upgrading Heat Only Thermostat to Wifi

I'm interested in upgrading some thermostats I have which control supplementary baseboard heating in several rooms. This is not my main heating system. I have 3 main forced hot air Heat/AC units on which I upgraded the thermostats to Honeywell Wifi thermostats several months back. They work great. Challenge with those was adding a C wire which wasn't present on my older thermostat cables, etc. However the thermostat cables were 5+ wire and went from thermostat to air handler.

On these baseboard only thermostats the thermostat cable only contains 3 wires of which only two are used. The two used wires are a Red going to an RH terminal on the thermostat which is jumpered to the RC terminal. The other wire is a white one going to the W terminal. Can I upgrade this type of thermostat to the same Wifi types I used elsewhere? Would I have to run new thermostat cable since these are only 3 wires? (2 used, 1 unused). The other end does not go to the air handlers - how would they need to be connected at that end?
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Old 12-02-20, 02:41 PM
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Ideal solution: Heat only so you need R, W, and C (for power). Currently you probably have R and W. If three wires likely goes to the water valve or to a zone controller. At that end you have a C which can be connected to the free wire going to the thermostat. Sometimes the C is hard to find.

See what you have a the valves/controller and go from there.
 
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Old 12-02-20, 05:06 PM
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This where the other end of the two thermostat wires connect in the bottom of the image in the orange wire nuts connected to the heavier yellow wires
Not sure if this is a water valve or zone controller
 
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Old 12-02-20, 05:15 PM
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That is a Honeywell zone valve.
The red wires are the end switch and control the boiler. The yellow wires are the thermostat.

Can you post a bigger picture of the splices. I don't need to see the zone valve itself.
 
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Old 12-02-20, 06:27 PM
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Splices from thermostat near Zone Valve. the white thermostat cable from the bottom left comes from the thermostat. The white thermostat cable coming from the bottom right goes toward the air handler to what looks like another zone valve (see Image C)

Wires at The Thermostat

Image C

Close up of wires in Image C
 
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Old 12-02-20, 07:14 PM
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That was a bigger picture.....

This is a bigger picture.....

Just attach the green wire from the stat cable to the C wirenut splice. That's it.
 
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Old 12-02-20, 07:37 PM
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Love the blow up with annotations!

1. So if I use the Green wire as my C - the R, W & C are sufficient for my new Wifi thermostat? Don't need 5 wires?
2. What I was calling the second thermostat wire that seemed to go toward my air handler & near what looked like another zone valve you are calling "24v". What does that other zone valve near the air handler represent - one of my other baseboard only thermostat zone valves perhaps?
3. What do the thick Red Wires coming from the zone valve do?
4. When I make the C wire connection do I need to shut the breaker for the boiler?
Thanks
 
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Old 12-02-20, 08:09 PM
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1) with a boiler.... you only need three wires. There is no blower to control.
2) that cable carries 24v power from the transformer to both zone valves.
3) on a call for heat.... the thermostat tells the zone valve to open. When the zone valve is fully opened the internal end switch shorts the red wires telling the boiler to run.
4) I would connect the green to the stat C first and then to the C spice. As long as the splice doesn't touch ground you won't have any problems.
 
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Old 12-02-20, 08:44 PM
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I will give it a try. Some final questions.

- So the second zone valve represents another thermostat & I should be able to duplicate the process for a C wire at that zone valve as well? And any other of these baseboard only thermostats throughout my house?
- On my original thermostat there was a jumper cable from RH to RC, on the new thermostat do I still need that or can the Red just go to the R terminal?
 
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Old 12-02-20, 09:04 PM
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Use the R jumper on the new stat.
Yes.... each zone valve controls an area that would be monitored and controlled by a thermostat
 
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Old 12-03-20, 03:55 AM
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Thank you. I will let you know how things turn out
 
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Old 12-04-20, 03:22 PM
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Hi PJ

On your enlarged diagram: I had my cables reversed

The cable you label 24v is actually my thermostat cable. Does that change anything? I would think not since all you're still doing is splicing the C wires of the 24v Power and thermostat cables anyway but before I do it I would like to check.


On a totally separate note. Two of my other baseboard thermostats appear to be line voltage. I'm assuming I can't use this particular type of Wifi thermostat for those as per the manual.
 
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Old 12-04-20, 04:39 PM
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One point of clarification - I meant attach the C wire to the wire nut splice not the other C wire because the other end of the 24v cable C wire goes no where.

One thing that is confusing is that second zone valve doesn't have any thermostat wires going to it rather it has low voltage wires coming from what looks like a higher voltage switch box/transformer - could that zone valve be for one of the line voltage systems?
 
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Old 12-04-20, 04:48 PM
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Proper R and W placement is critical.
The R at the thermostat stands for 24v power.
The W at the thermostat stands for switched heating 24v.

Consider it this way..... R = 24v + and C = 24v - (even though we are working with AC.)

Post some pictures of the other wiring. I may recognize what was done.
 
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Old 12-04-20, 07:47 PM
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Close up : I've labeled the thermostat Cable - "Cable A" to the right & the other Cable which goes to near air handler "Cable B" on the left


Zoomed Out view with wires going into Zone valve


This is the other end of "Cable B" near the air handler. Of note the red curled wire is not from Cable B, one of the curled white wires is from Cable B


This is a zoomed out view of what's going on in air handler room. The Red wire from Cable B seems to go up top of air handler and is wire nutted to heavy red wire going into that switch box, the curled white wire from Cable B is pigtailed to another curled white wire and a heavy yellow wire going to that zone valve.


Close up of that junction box with switch on top of air handler. That switch shuts my air handler if turned off
 

Last edited by PJmax; 12-04-20 at 09:38 PM. Reason: labeled pics
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Old 12-04-20, 09:44 PM
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Are we done with the first part ? Is that working ok ?
It looks like picture A was already posted... is that correct or does it just look similar ?
 
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Old 12-05-20, 08:59 AM
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I'm not done with the first part because the labels were not accurate during our original exchange so I was trying to get clarification:
Picture A was already posted but I was trying to accurately label the cables and give some more detail
Regarding the first part - on the enlarged labeled diagram YOU sent back to me - the cable you labeled stat is NOT the cable that goes to the thermostat but instead that cable actually goes down toward the direction of the air handler(What I labeled "Cable B" -you can see where it ends up in Pictures C,D, & E) - possibly the 24v cable?
Again back to Picture A - the cable you labeled 24v on the enlarged diagram is actually my Stat cable (What I labeled "Cable A") . So basically the labeling of the cables 24v vs Stat are reversed from that blown up labeled diagram you sent me - Does this change anything with the hookup other than of course using the extra "C" wire from the actual thermostat cable?
What I tried to show in Pictures C, D & E was what was going on at the air handler to:
1. Confirm that the 24v Cable from Picture A is actually the 24v cable
2. Figure out what was going on with that other zone valve seen in Picture D (near air handler) since it doesn't have a distinct thermostat wire going to it
Apologize for the confusion. Thanks for your patience
 
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Old 12-05-20, 09:28 PM
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the white thermostat cable from the bottom left comes from the thermostat. The white thermostat cable coming from the bottom right goes toward the air handler to what looks like another zone valve
You posted this originally. So this is backwards.

The new diagram reveres the function of the cables.
That means your current thermostat cable wiring is or was backwards from what it needed to be.
 
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Old 12-05-20, 11:39 PM
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You're correct about what I originally wrote. You're current diagram has the thermostat & 24v cables properly labeled

However my current thermostat cable has it's red wire going to the wire nut you labeled W & has it's white wire going to the wire nut R - This is how it was originally wired(not by me) & it seemed to function fine. Are you saying the "correct way it should have been wired is with the thermostat cable's white wire going to the W wire nut & it's red wire going to the R wire nut?

Before your reply I did try connecting the C wire as you show above (with the only exception being the thermostat white and red wires are reversed from your diagram above) & my new thermostat briefly powered on and then shut down and will not power up. When I check the voltage at the 24v power I only get a reading of about 3.5 volts. I spoke with Honeywell and they said the new thermostat needs 20-30volts to work. Does this make sense that my old thermostat would work even if it's only getting 3.5 volts? Why would it work if it's white and red wires were reversed?
Could you figure out what they have going on at the air handler end?
 
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Old 12-08-20, 09:33 AM
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Hi PJ - just revisiting our post since never got an answer.
Any thoughts on my follow up post?

In the interim I spoke with Honeywell - they recommended using a 24v adapter/transformer to basically provide power. I purchased several of them & hooked it up as instructed. (As per their instructions one wire of the adapter to the C terminal & one to the RC terminal and then remove the jumper on the new thermostat between RH/R & RC, hook up the original thermostat wires Red to R &White to W . It seems to work very well. - Although the first adapter I tried made such a loud humming noise I had to replace it.) Fortunately the location of this thermostat will allow me to easily hide the adapter wires and where it plugs in to the outlet. Curious if they make some form of transformer that accomplishes the same thing that you can hard wire to an electric source like an outlet that is completely hidden.
 
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Old 12-09-20, 10:49 AM
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I was out on an emergency for a day. Now I see pictures aren't posting.
 
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Old 12-09-20, 11:07 AM
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A WiFi thermostat is not an "upgrade" more like a downgrade those old mechanical and/or mercury vial thermostats are way more reliable then modern designed to fail made in China JUNK!

I mean why do you need to set your thermostat remotely?
I leave the heat thermostat on 65F all heating season the AC stays on 62F during the cooling season so no reason to keep adjusting it.

This trend of replacing working great quality stuff with modern low quality CRAP has to stop especially this LED everything lighting.
 
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Old 12-09-20, 01:22 PM
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So I often find upgrades are not improvements but when it comes to these Wifi thermostats I actually find they work great. Maybe if you live in a certain place and live by yourself leaving the heat & AC set at one temperature might work. Would never fly in my house
 
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Old 12-10-20, 04:33 PM
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I live by myself (well me and my Cat) so I guess that is why!

I used to live in a big old house I had a 25' X 15' X 12' (ceiling) there was only 1 heat vent in that room and a small one at that!

The main and only thermostat was in the hallway it was on 80F the room was only 62F my Moms room was 86F she used the AC (window rattler) all year to get it to a reasonable temp!

So I can see where you are coming from Lol!

I am an IT tech by trade and I hate the trend of electronic & computer controls in modern appliances and other things that have no need for that only more things to go wrong.

I for one welcome technology in the medical field though.

The only WiFi thermostats I will not install for anyone is any one made by Nest as on more then one occasion it actually did harm to the AC system no fault of my wiring or install but a Nest firmware bug. Luckily Google actually said sorry (for once!).

they had a real tech fix it one of my friends got a whole new condenser as the compressor fried as the Nest kept trying to start it with no delay luckily for Him it was near the end of its life anyway so free fix it was a 2009 R22 unit. So not all modern tech is an "upgrade" or "downgrade" it is what it is I guess.
 
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Old 12-10-20, 05:16 PM
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The guys who normally services my AC/Heating also was not a fan of Nest - claimed he saw many problems with them. Thought Honeywell's were better.

On our side topic - technology upgrades are indeed a mixed bag. Most software program upgrades I find less user friendly than prior versions. Many of the new cars I find the technology more distracting & dangerous.
Happening to be in the medical field - most upgrades are better especially advances in certain procedures but it too has issues with technology
 
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Old 12-10-20, 05:49 PM
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Lol! Don't get me started on modern vehicles!
I find most modern software is written very sloppy (code wise) back in the old days coders were very careful as computers need every last resource they had available at the time, now that the hardware power is way more then most things need they don't optimize the code for space and CPU power savings as they did back then.
Yes the Honeywell ones are way better then Nest units not real familiar with EcoBee units though.
 
 

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