Liking our new Ecobee thermostats

jesmed1

This is not a question/problem, just me saying how much I'm liking our new Ecobee3 lite thermostats, which helped us solve an ongoing heating problem.

I maintain a 100-year-old 4-unit condo building in the Boston area. It's divided down the middle into two halves. One oil boiler on each side of the basement heats its own half of the building (two condo units, one on the first floor and one on the second floor.)

An ongoing problem when I moved in 10+ years ago was the lack of heat regulation on the second floor. The one thermostat per boiler was on the first floor, so the second floor condo had no separate control for heat. This caused ongoing problems for the upstairs condos, which were often either too hot or too cold.

It took me several years to find and fix a number of other underlying problems, such as air trapped in radiators, lack of proper air management devices on the boiler piping, thermostats placed in the wrong places, incorrect swing settings, air leaks through windows, etc. Once all those were fixed, the heating system worked more evenly, but the upstairs units still lacked controls.

I had considered installing smart thermostats in the past, but the lack of a C wire was one of the impediments that held me back. After doing some research, I finally decided to try the Ecobee3 lite thermostat in one unit. I chose the Ecobee over the Nest because the Nest has no user-configurable setting for the swing, and I had found by trial and error that our cast iron boilers needed to have the thermostat programmed for the correct swing setting for optimal run times. (Ecobee doesn't call it a "swing" setting; they call it the "heat differential temperature.")

After installing an Ecobee3 lite in one of the condo units, I found that a "heat differential temperature" of 1.0 produced roughly the same boiler run times as our previous "dumb" thermostat had with a swing setting of 0.75 degrees (about 40 minutes).

I also found that the graphic data display available at beestat.io was extremely helpful in monitoring boiler run times and seeing how the temperature in the condo unit varied with the boiler runs.

Then after installing the Ecobee, I read that there were remote sensors available that would provide temperature data in other rooms wirelessly. I realized that one of those sensors placed in an upstairs condo unit could function as a de facto thermostat for the upstairs units, as it would feed temperature data back to the thermostat and help regulate the upstairs temperature.

So I got a sensor, paired it with the Ecobee thermostat, and gave it to the upstairs condo owner to hang on her wall. Using the beestat.io web-based app, I could then monitor the temperature range in the upstairs unit. As it turned out, with the downstairs Ecobee thermostat set at 69, the upstairs unit temperature ranged from 68-70, while the downstairs temperature ranged from 67-69, and that was fine. The thermostat averages the two temperature readings and uses that average as the input for its control feedback loop, so one unit never gets too hot or too cold.

Once I saw how well the setup worked, I installed a second Ecobee thermostat + remote sensor in the other two condo units, and the heat in those units is now also well balanced.

I'm now kicking myself for waiting so long to do this, as having a remote sensor upstairs helping to regulate the heat is a game-changer for the upstairs condo owners who previously had no control over the heat.

One note on the Ecobee and other smart thermostats is that the power requirement can be a problem in certain setups. We have only a 2-wire, heat-only thermostat setup, so we don't have the complication of added A/C and fan controls. Even so, we did need to find a separate 24 VAC power source for the Ecobees. I was going to buy a separate plug-in transformer to install in the basement near the boilers, but then I realized that our building doorbells all run off a dedicated nearby 24 VAC transformer. So I added some multiplex connectors to the transformer and ran power wires from there to both Ecostats, and that works well. For a setup like this, the 24 VAC power goes to the Rc and C terminals on the Ecobee. The aquastat relay wires on the boiler go to the Rh and W1 terminals on the Ecobee.

So, thanks to the good folks at Ecobee for engineering an outstanding product that helped solve a longstanding problem for some condo owners who previously had no way to regulate their heat.

I might also say that I got helpful answers from the Ecobee tech support people in online chats to answer some questions. They were busy on cold weekends, so I sometimes had to wait, but once I got hold of someone, they invariably were able to answer my questions.

EBEBRATT-Ed

Just be aware that some doorbell transformers were very small in the VA department and that some were 16 volt transformers.

Other than that possibility sound like you found a good fix!!!

Now all the "nest" people will be calling to hook there nest's to there doorbells!!!!!!

I am staying away from that and will let @EdTheHeaterMan come up with a doorbell to nest hook up.

So you are saying that Rc & C are completely isolated from Rh & W in the Ecobee?

EdTheHeaterMan

Thanks for this valuable information. And it is nice to hear from you again without needing to solve a problem. You may have even solved some problems for others here. I am going to bookmark this Discussion for future reference so I can help others with your same problem. I would never know this information since I don't work on customers systems anymore, and have no way to test these different options. BIG THANKS again @jesmed1

jesmed1

EBEBRATT-Ed said:

Just be aware that some doorbell transformers were very small in the VA department and that some were 16 volt transformers.

Other than that possibility sound like you found a good fix!!!

Now all the "nest" people will be calling to hook there nest's to there doorbells!!!!!!

I am staying away from that and will let @EdTheHeaterMan come up with a doorbell to nest hook up.

So you are saying that Rc & C are completely isolated from Rh & W in the Ecobee?

Thanks for the warning on the transformer voltage. Yes, I confirmed with a multimeter that the transformer is 24VAC. I couldn't find an amperage rating on it, but it's enough to ring our old-fashioned coil-wound buzzers. Both Ecobees have been running on that transformer for a week now, with no problems.

For how to connect the power to the Ecobees, I followed the advice of a number of other Ecobee users on Reddit and elsewhere who said that, for a 2-wire heat-only configuration, external power from a separate 24 VAC transformer should be applied to Rc and C. So that's what I did, and it works.

I don't want to comment further on whether or not Rc and C are completely isolated internally from Rh and W as you asked about, as I don't know enough about the internal circuitry and don't want to lead people astray. All I can say is that I followed the advice of other Ecobee users and connected my separate 24 VAC power supply to Rc and C, and that is working on both the Ecobees I installed here. Again, that is with the aquastat relay wires for heat connected to Rh and W on the Ecobee.

I will repeat that, for people with more than 2-wire "heat only" connections, the above will NOT work. The Ecobee comes with a separate "power extender kit" that gets wired differently for those cases.

jesmed1

EdTheHeaterMan said:

Thanks for this valuable information. And it is nice to hear from you again without needing to solve a problem. You may have even solved some problems for others here. I am going to bookmark this Discussion for future reference so I can help others with your same problem. I would never know this information since I don't work on customers systems anymore, and have no way to test these different options. BIG THANKS again @jesmed1

Thank you @EdTheHeaterMan . Nice to be able to give back a little to the good people here on HH who have been so generous to me with their time and expertise.