A white-rodgers generic cheapie that came with the new furnace 3-4 years
ago, specifically. Takes AA x2. New duracells (with use-by dates several
years in future) seem to go flat in 3-4 months, and the thing loses all
the settings. Doesn't seem like there should be a lot of juice used
driving a couple chips and that tiny LCD.
Given that power is available from the furnace, why do these things need
more than a button cell for memory backup, anyway?
aem sends, adding another item to the shopping list for tomorrow...
I was going by your description "generic cheapie". There really is no such thing
as a "better brand" in today's day and age unless you spend a thousand bucks.
It's all chinese crap. I've seen sony (reputation earned in the 70's, but not
since and now made mostly in the asian rim ) do crap that would embarass a
fly by night walmart brand.
I have a luxtx1500 that is is also a POS. It hasn't had any trouble running
a year on it's 9v battery.
There are many ways a poorly designed thermostat can run the batteries down in
short order. Junk output design with current wasted going through pull down
resistors on the transtor bases -- use of cheap bipolar output transistors
instead of higher quality MOSFETs.
ESD sensative chips partially damaged during assembly.
My UPM Thermostat seems to go several years on fresh batteries. I don't
seem to remember it loosing settings when the batteries are changed...
but I could be wrong its been quite a while since I changed them.
I just read the manual for my thermostat - it suggest you should replace
the batteries once a year but it will let you know when the battery is
getting low. If the batteries are replaced within 20 seconds the
thermostat will not loose the programing.
If there is a blue wire in your cable, assuming it's a 5 conductor
thermostat cable, the blue wire would normally be hooked up at the
furnace and the thermostat so it would have 24vac power. The normal
color code would be for the red and blue wires to be the 24 volt
supply. I always install digital thermostats so they are powered
from the air handler and have batteries for backup. The inexpensive
thermostats may be battery only but most of them I come across have
the option to also use 24 volt power. The reason for AA batteries
is that a relay/relays inside the thermostat needs to be activated
to operate the HVAC system.
Wire colors are not standardized, but you are correct, without both the
"R" (24V) and "C" (common) connections being wired to the thermostat, it
has to run entirely off of the batteries and while an LCD display takes
little power, a backlight and most importantly the fan and stage relays
do take a fair amount of power relatively speaking. If the "R" and "C"
are wired to the thermostat it's powered by the AC and the batteries are
only used for setting backup during power failures and last a lot
Pop the thermostat off the sub-base and see how it is wired. The most
common reason for not having the complete "R" and "C" connections is not
having enough wires in the existing cable.
Nope, all 5 in place. Next time I run across my VOM, I'll put it across
the R and C leads, and see if there is juice. Brand new batteries in
there now, and it seems happy. Now I just have to remember how to
program the damn thing. And I did write today's date in pencil on the
inside of the lid, since my memory is not so hot any more...
Chuckle. yeah, mine too. But the button labels are on the outside of the
case, so you keep having to flip it over to remember which one to punch
next. Shoulda been on the inside of the fold-down door. I'll figure it
out, it is just one of those tedious annoying things that could have
been made a lot simpler for a couple more bucks. I might even have the
paper instructions Someplace around here, but right now I haven't a clue
Does the TS have a reset button?
That will set it to factory defaults I think, mine does. (energy star
suggested settings for a 5+2 type)
I never made any custom settings, so the default is fine for me.
The whole programmable setback thing is not applicable for a lot of
folks since it presumes nobody is home during the day, which is not the
case for folks who are retired, work from home, stay at home parents,
How do you figure that? We used[*] a setback thermostat not only for daytime
but nighttime, as well. AAMOF, the nighttime setback was further (59F) than
the day (62, IIRC). We set the temperature for morning and evening to 66F and
kicked it up if we got cold.
[*] Don't now because heat pump recovery is an oxymoron.
Guess age is starting to rear its ugly head for me. I can't sleep well
in a 59 degree room any more. Not to mention, those middle-of-the-night
walks are hard to get back to sleep from, at that temp.
I like it cold while sleeping (it's just another blanket). We keep it about
64F now that we have a heat pump. I'd rather have it cooler but even 64F is
stretching it for the morning shower and as I said, heat pumps don't recover.
Heat isn't nearly as expensive as it was, though. Moving from Vermont to
Alabama has changed a few things (heat bills, taxes,...). ;-)
Yes, and yes. Heat pumps are nice and efficient, but more than a 2
degree change in set point and you're on aux backup heat. Yes also, I
don't like a drastic change in night temperatures either and I also find
getting back to sleep after the 3am page is difficult if the temps have
my cheapo programmable TS works fine without any setback programmed.
Plus there's an OVERRIDE switch for when you're home.
It cost me $15 at Home Depot about 15 years ago.
having a digital TS is better,as it sets to temp more accurately.
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