ecobee thermostat with weil mclain boiler

Jamie Hall

Just sort of a follow up on @SteamBoiler 's comments on the uneven heating with a T87 -- or for that matter any other dumb thermostat. What he is complaining about is not the fault of the thermostat, but of other problems leading to imbalance in the overall system (although misadjustment of the T87 may have played a part).

And to @pgf 's comments on the apparent inaccuracy of his thermostats. The error in setpoint -- not turning on ore off when expected -- is commpn, and is the result of sloppy installation. The mercury T87s were. and are, very sensitive to being level in that regard. It doesn't take much to throw them off. The face thermometer on them can be calibrated quite easily.

And they run forever.

What they don't do, though, is provide the kind of magic that he wants. All they do is work.

pgf

Just wanted to follow up on this. Least I can do after jumping on someone else's thread to get my questions answered. :-)

I got the Ecobee (a "3 Lite"), and it works as promised. It's been in the 20s, and the boiler runs every hour to hour and a half, or thereabouts, for between 15 and 20 minutes. I have the minimum cycle set at 8, but I think I've only seen it do that when I mistakenly bumped the temperature up and started it by accident. It seems to kick on 1/2 degree below setpoint, and shuts off at the setpoint.

There's some overshoot early in the day, but after that it's pretty good, varying between (setpoint) and (setpoint - 1/2 degree). I do get short-cycling in the morning, as it's coming out of setback, but only after its been running for 45 minutes or so, and has come up by 3 or 4 degrees. I'm going to reduce the setback, and also ramp the temperature more slowly, to give it some rest stops along the way.

I have learned since purchasing that some Ecobees have been known to lock up and stop functioning (at all!) after a power glitch. (I can hear the T87 fans laughing all the way over here!) Since we do get glitches, and because hey -- why should this piece of modern consumer electronics be any different than other failure-prone products, I'm going to wire a failsafe thermostat in parallel, probably set for 60F, which is the lowest we'd ever set the house heat. I'm likely going to use one of these, unless someone things it's a terrible idea. It'll fit neatly into a new semi-hidden hole in the mounting board for the Ecobee.

Many thanks for your help!

paul

pgf

Just one more comment: my pair of T87 thermostats did, indeed work. They were solidly reliable, even if, after many many attempts, I couldn't get them calibrated properly. Maybe my problem was having two of them -- if I'd only had one, I'd never have known it was wrong!

But in the end I'm a data-phile, and I do love the graphs I can get out of the new stuff.

Waher

The 1/2 degree below setpoint is an adjustable setting.

https://beestat.io/ is a much better portal for reviewing most of the cycle data.