I have two zones of forced hot-water, propane-fired heat in this building: a Nest Thermostat E in the office, and a Nest 2nd Gen up in the studio. This morning, the Office's Thermostat E started reporting E195 "No Power to R Wire Detected."
The Studio's 2nd Gen has no such issues. Both are connected to the same boiler, just different zones. The zones are served by Taco valves (if that's relevant).
Back to the "E" in the Office: It shows that there is Power coming into it on the Diagram, though, and if I remove the wires from the back plate I can see voltage across them.
Any idea what's going on? Is the "E" more sensitive to, say, a beginning-to-fail transformer than the 2nd Gen is? Or is the valve on this zone starting to fail or something? I was able to get heat to flow by forcing the valve open, so clearly the boiler itself works fine...and the zone in the Studio works fine, too, wireless and everything.
I'd appreciate any thoughts, of course. Thanks!
Thank you for taking the time in letting us know about your inquiry. Let's see what's going on.
It appears that your system might not provide enough power or any power to either the thermostat or a specific wire (so the thermostat can’t complete a circuit and shows aa report). How's your thermostat? Are you still getting the same report? If so, please try the steps here:
Let us know how it goes.