how long should programmable thermostat batteries last?

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...

Reply to
aemeijers
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What do you expect from a POS?

Reply to
AZ Nomad

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.

Reply to
Ned Flanders

POS? I thought White - Rogers was one of the better brands.

Reply to
Ed Pawlowski

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.

TDD

Reply to
The Daring Dufas

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.

Reply to
Ned Flanders

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.

Reply to
AZ Nomad

Sounds like either the thermostat is defective, you had a bad batch of batteries or aren't storing the batteries in the best place to preserve their shelf life...

~~ Evan

Reply to
Evan

Do you have a battery meter- gauge, Ive rarely-once in a while found one weak cell out of a bunch, one weak cell ruins a group to show dead in an apliance. Get one of those inexpensive cell testers that puts a load on the cell to mimic an actual load so you will have a actual reading of the worth of the cell, mine was maybe 7$ at radio shack. Once in a while I test a dead battery operated gizmo and find just one dead cell ruining the whole pack. I dont know what happens when a thermostat goes battery dead but I would hate to have the heat "Lock On" while I am away. I have saved alot of money and batteries by using a battery load teaster by not junking good batteries. Or the thermostat is defective, draining them, and needs replacing.

Reply to
ransley

I store them in the plastic blister pack in the kitchen junk drawer ten feet from the stove against an outside wall. Never frozen, never above

75 degrees. I suppose they could have gotten skunked sitting in a tin can in a sunny freight yard somewhere, in the supply chain. No idea where the Duracell factory that supplies this part of the country is. I'll buy a fresh pack today with the longest date I can find, and try again. I'll also put a tiny post-it inside the case with the date, so I can be sure next time, how long it has been.

-- aem sends...

Reply to
aemeijers

My Honeywell 7 day programmable with large backlit display needs new AAx3 cells every 8 months. It has a low battery indicator and although I've never let it go to where the batteries were completely drained, it retains its programming while you replace the AA cells. This model is about 10 years old.

You should probably replace what you have with a Honeywell.

Reply to
Jeff The Drunk

I have a cheap "PerfectTemp" that uses one AA. The batt will last 3 yrs and not lose anything when changed.

Reply to
Bob Villa

Good for you. Here's a pat on the back a cookie and a cup of milk!.

Reply to
Jeff The Drunk

I'm guessing you have a problem with the thermostat. We installed a White Rogers two-stage thermostat in our new home about 1-1/2 years ago and it is fine. From your description ours might be a little more capable then yours but it certainly isn't top-of-the-line.

We had a similar WR unit in our previous home and I can only recall one battery replacement in nine years.

RonB

Reply to
RonB

aemeijers wrote in news:59KdnbwSNMcu5lfWnZ2dnUVZ snipped-for-privacy@giganews.com:

We have 2 white-rodgers thermostats (WR#: 1F80-51) with 3 AA batteries each, and they seem to last rather long. The WR A/C thermostat has 2 AA's and they were gone now, but surely did last during the previous cooling season (north Jersey, and last year was a cool summer with relatively little A/C usage).

YMMV

Reply to
Han

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 longer.

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.

Reply to
Pete C.

Got a W-R thermostat-replace the batteries once a year before I go away for some part of the winter. Been doing this for years as a safety measure because a battery failure will shut down the furnace. This year, after coming home, I put the original batteries back in the stat and its operating properly. My guess is that you have a problem with your thermostat. MLD

Reply to
MLD

As has been mentioned, the furnace can (maybe) provide power to the thermostat with the batteries being used as a power fail backup. However, many early furnaces didn't bring the return lead for the 24 volts AC to the thermostat. I know on my Honeywell, which is in a motorhome, it runs on batteries 24/7 because there is no 24VAC. The motorhome HVAC uses 12 volts DC for control so that it can be used in a no AC environment off the the batteries. Honeywell says that the batteries can be either used as a backup or as the main thermostat power. There batteries seem to last more than a year, but given that we don't use the motorhome continuously, that doesn't say much. The Honeywell does have relays in it that operate the furnace and AC units and I'm sure that is a significant drain on the battery. In my old house, I had a Honeywell which ran off batteries (no 24VAC return) and they would last several years. And, it also had internal relays to operated the HVAC system. The OP must either have a bad thermostat or one that is poorly designed.

Reply to
Art Todesco

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...

Reply to
aemeijers

aemeijers wrote in news:59KdnbwSNMcu5lfWnZ2dnUVZ snipped-for-privacy@giganews.com:

Maybe the TS is defective? some bad component causing an excessive drain.

I have a similar inexpensive TS,and it's 2 AA alkalines last for years. They should last nearly the regular storage life of the cells. I don't use Duracells,though;they leak far more than other brands.

I decided I'd change the batteries out every year,at the time change. I buy bulk packs,so they aren't a big deal.

Reply to
Jim Yanik

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