Here is a record in emails to neighbors and to Nest and forum posts of our Nest's failure
during the arctic vortex, how I fixed it, and some of the complaints I
lodged wit
From dyoung@pobox.com Tue Jan 7 01:03:45 2014
Date: Tue, 7 Jan 2014 01:03:45 -0600
From: David Young
To: wuna-list@googlegroups.com
Subject: if your Nest Learning Thermostat is freezing you
Neighbors,
We have been using the Nest Learning Thermostat (nest.com) at our house
since this summer. It's worked pretty well until just the last few
days, when it developed a bad habit of running down its battery. This
basically ruined my day, and if your Nest thermostat has the same bad
habits as ours, then it will ruin your day, too.
Skip to the end for my solution.
The Nest thermostat runs on a battery that charges from current on the
wires that control your furnace, fan, and air conditioner. Depending
which wires are present in your house, the Nest thermostat may have
ample current, or a trickle. Ours had a trickle, but it was enough to
keep the battery topped-off.
When the Nest thermostat runs down its battery, it turns itself off to
charge. While it charges, it is not calling for heat from your furnace.
So your house cools until the thermostat has charged up enough to start
up again.
Our thermostat was in a cycle where the battery would charge up to the
minimum, then turn back on. Meanwhile the house had cooled. When the
thermostat turned back on, the furnace would run continuously, but not
long enough to make up for the heat losses before the thermostat ran
down its battery and turned off again. This cycle repeated all night,
and we woke up to a cold house this morning.
(The cycle had begun yesterday or the day before, but the weather was not
so bad when the cycle began, so the cycle was fast enough to keep us warm.)
THE FIX
To make a long story short, the way that I fixed this was to run out
to buy a USB cable that had at one end a micro-USB connector, and on
the other, a USB connector that plugged into my laptop. (There's
full-size, mini, and micro USB. Your Android phone might use a
micro-USB connection.) I pulled the thermostat off the wall, and
charged it on my laptop. I let it charge for several minutes. I put it
back on the wall. Finally, I *turned off the Wi-Fi networking*. Wi-Fi
can drain the thermostat's battery quickly, and the latest software
for the Nest thermostat seems to break the built-in battery-conserving
measures. Now that the Wi-Fi is off, the thermostat has stopped running
down its battery, and the house is warming to a comfortable temperature.
The long story is too long, but there were a couple of conversations
with Nest technical support in there, helpful suggestions were offered
but no *solutions*, things got worse before they got better, et cetera.
Dave
--
David Young
dyoung@pobox.com Urbana, IL (217) 721-9981
From dyoung@pobox.com Tue Jan 7 13:55:52 2014
Date: Tue, 7 Jan 2014 13:55:52 -0600
From: David Young <dyoung@pobox.com>
To: <redacted>
Subject: Re: Fwd: [wuna-list] if your Nest Learning Thermostat is freezing
you
> <redacted private reply about my Nest troubles, asking if I tried to>
> <connect a common ("C") wire>
I tried that, and that's when things took a turn for the worse! :-) I
found a disconnected blue wire, and a disconnected black wire. Neither
had been connected to my old thermostat, so I had not connected them to
the Nest. I read that the common wire was commonly a blue wire, and
there was 24 VAC between the blue wire and some of the other thermostat
wires, so it looked promising. I connected it to the "C" terminal.
When I put the thermostat back on the wall, the red LED started to blink
like it was charging, so I left it for a while in the hopes that it
would charge more rapidly and completely than before with the help of
the common wire. Meanwhile I shoveled the driveway and scoured the web
for more information. It got really, really cold inside, but I had
hope. The thermostat kept charging, but it never woke back up.
After I gave up and charged the thermostat through its micro-USB port,
and put it back on the wall, I got an "e23" error. The solution was to
disconnected the blue wire from the "C" terminal. Maybe my blue wire
isn't a common wire, after all.
I think that the root cause of our troubles is the 4.0 software update.
The Nest support site hints at a serious power-draining bug involving
the Wi-Fi. It seems that they have known about the problem since Dec
8. They're downgrading affected thermostats, including ours, to version
3.5.3.
We noted the reboot loop by accident a couple of days before the
temperatures went haywire, so I wonder if many more people are not
affected by the bug than anyone realizes.
Dave
--
David Young
dyoung@pobox.com Urbana, IL (217) 721-9981