# thermostat doesnt move down in temp



## noquacks (Jun 5, 2010)

People,

Going to my mothers house to check out her thermostat- she says its a honeywell, and when depressing the down button to trip ac, it is stuck on 79 degrees. But, if she pushes the up button, it will go up. Anything I should check for while Im there troubleshooting? I dont have internet there, so thats why Im asking now, ahead of time.


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## jmon (Nov 5, 2012)

Do you have model number? Before you buy a new one, check out some of the suggestions in this link while were waiting for some experts to arrive. In this link, the homeowner had to go for new thermostat. 

You can print out the advice and take it with you. Just a suggestion, google your model number and print out manual for it. Take it with you as well, it may help, being how you won't have the internet to help you once you are there.


link here


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## gregzoll (Dec 25, 2006)

If you have pulled the unit off the plate on the wall, changed the batteries, and it still does the same behavior, time for a new one.


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## ben's plumbing (Oct 6, 2011)

yep do what greg said ...change batteries if problem still exist change out stat....ben sr


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## gregzoll (Dec 25, 2006)

Single stage, Heat pump w/o Aux/Em heat http://www.lowes.com/pd_356348-7449...1950__?productId=3464344&Ns=p_product_price|0 If they have a Heat Pump with Aux/Em heat http://www.lowes.com/pd_356346-7449...1950__?productId=3464342&Ns=p_product_price|0 About as simple as you can get.


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## noquacks (Jun 5, 2010)

OK...Im off to see my Mother. (time to visit her anyway......LOL)


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## noquacks (Jun 5, 2010)

OK, its a Honeywell, about 10 yrs old, Model T8411R. other #'s next to it, if it matters, are 1028(2) 0048 2A.

I yanked it off the wall, and it has no battery (hard wired, right?). Then, if I switch it to OFF, then back to COOL the temo first goes to 79 SET, then after a few seconds, it reverts to 81. At the 81 position, it also shows the * above AUX. The * blinks. The stat wont go below 79 . UP/DOWN buttons simply quit working/moving. They are stuck. Is it time to throw the stat away and get new?


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## hvac5646 (May 1, 2011)

noquacks said:


> OK, its a Honeywell, about 10 yrs old, Model T8411R. other #'s next to it, if it matters, are 1028(2) 0048 2A.
> 
> I yanked it off the wall, and it has no battery (hard wired, right?). Then, if I switch it to OFF, then back to COOL the temo first goes to 79 SET, then after a few seconds, it reverts to 81. At the 81 position, it also shows the * above AUX. The * blinks. The stat wont go below 79 . UP/DOWN buttons simply quit working/moving. They are stuck. Is it time to throw the stat away and get new?


yep.
time for a new one.


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## gregzoll (Dec 25, 2006)

If she wants something simple, go with the second one I posted. Home Depot has the RTH5100B, but it does not allow you to set set point temps, or have auto-changeover. Just remember to either use a piece of paper to write down what color wires go on what terminals, so that you can hook it back up to the new wall plate.

I hate the little tags, because they tend to fall off, while pulling the wires through the wall plate. And always, shut the breakers off on both the furnace and heat pump, before doing anything, when changing out the thermostats. Do not need you burning out the circuit board.


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## noquacks (Jun 5, 2010)

Going to HD........big thanks.


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## gregzoll (Dec 25, 2006)

noquacks said:


> Going to HD........big thanks.


HD did not show the one that I stated as the better, they showed on their site a lower end model of that version.


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## noquacks (Jun 5, 2010)

OK, so I bought a Honeywell at HD, one for a heat pump, connected it, and numbers now go up/down no problem. But, Now, NOTHING works. No ac. Man. Could this mean the R22 is low and comp does not kick on? Should I check for static psi? Heeeeelp, people!!!!!


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## noquacks (Jun 5, 2010)

Oh- this might meean something- the old one had the white wire to C, and nbow new one says to connect the white to AUX. Thats what I did. It is for, I believe, the elec heat strip.....


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## gregzoll (Dec 25, 2006)

noquacks said:


> OK, so I bought a Honeywell at HD, one for a heat pump, connected it, and numbers now go up/down no problem. But, Now, NOTHING works. No ac. Man. Could this mean the R22 is low and comp does not kick on? Should I check for static psi? Heeeeelp, people!!!!!


Means that you probably got the wrong one, or hooked it up wrong. What is the model# of the one you purchased at Home Depot, and did you remember as I stated, to shut all power off first to the indoor and outdoor units, before changing out the thermostat, write on a sheet of paper, the color of the wires and terminals they connected to on the old plate, for the old thermostat? Did you also go through the setup instructions for making sure the new thermostat was set for a heat pump with heat, not just heat only?

There is a lot more to setting up the new electronic thermostats, than just hook them up, and turn the power back on. Something like this is at most a 15 min. project.


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## HVAC1000 (Dec 12, 2012)

gregzoll said:


> Means that you probably got the wrong one, or hooked it up wrong. What is the model# of the one you purchased at Home Depot, and did you remember as I stated, to shut all power off first to the indoor and outdoor units, before changing out the thermostat, write on a sheet of paper, the color of the wires and terminals they connected to on the old plate, for the old thermostat? Did you also go through the setup instructions for making sure the new thermostat was set for a heat pump with heat, not just heat only?
> 
> There is a lot more to setting up the new electronic thermostats, than just hook them up, and turn the power back on. Something like this is at most a 15 min. project.


There may be a little fuse on the control board in the air handler. Check it to see if it is blown. If so replace it and you should be good


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## noquacks (Jun 5, 2010)

gregzoll said:


> Means that you probably got the wrong one, or hooked it up wrong. What is the model# of the one you purchased at Home Depot, and did you remember as I stated, to shut all power off first to the indoor and outdoor units, before changing out the thermostat, write on a sheet of paper, the color of the wires and terminals they connected to on the old plate, for the old thermostat? Did you also go through the setup instructions for making sure the new thermostat was set for a heat pump with heat, not just heat only?
> 
> There is a lot more to setting up the new electronic thermostats, than just hook them up, and turn the power back on. Something like this is at most a 15 min. project.


Yes I did, Greg. I DID get the wrong one- first. Then, I had to go back to HD, and get the RIGHT one (for heat pumps). I hooked up the RIGHT one, with all the breakers off (AC and circuit for the stat). I learne dthis lesson years ago. Yes I did read the instructions, cuz at first, I had some confusion on colors/screws. I also added batteries, about which the stat said "connection to "C" is optional if using batteries, which is confusing to me. Does this mean I done need the dumb batteries IF I connect the blue wire to "C", the power source?

Thanks

I wiol check that fuse tomorrow, though.


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## gregzoll (Dec 25, 2006)

If you have C hooked up, you do not need the batteries. I still install them, so that if power goes out, the settings are kept on the thermostat.

As for the colors being confusing, as long as you connected the wires regardless of the color, for what terminal they were on on the old plate, to the new plate, you should not have had a issue. Now the question is, did the Heat pump work last year, or the year before, before the old thermostat went out?


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## noquacks (Jun 5, 2010)

Thanks for the continued persistent help, Greg. Good to know about the batteries- manual is so unclear.

Also, New plate vs old plate- no way they match. I guess they "update" stuff. But yes, MOST terminals match (R for red is the same, etc), but goofy stuff like W1 and W2- they are gone from the new stat as markings. They are using new "names". But I will review them again later todfay, to make double sure. (I have tto go to Moms house again......)

Only thing bugging me is new stat diagram says if I had a blue wire (which went to C on old stat) Im supposed to connect it to C now. But then, why do they have also a B terminal? If B wire goes to C, what goes to B?


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## gregzoll (Dec 25, 2006)

Keep in mind that W1 & W2, etc. if there is a 1 & 2, means 1st & 2nd stages. Nothing has changed in how you hook the thermostats up to the units, you have to though make sure you get the correct thermostat for the indoor & outdoor units, otherwise, you are right back at the store, to exchange for the correct one.

As for the manuals for the Honeywell thermostats, they are very clear in the instructions.


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## noquacks (Jun 5, 2010)

Funny- 2 days later, having done nothing, the system WORKS! Sheesh- I didnt do anything to it since that day. Guess I wired it rioght. But why didnt it respond when I installed it (to test the system)? Oh well, gotta be thankful . And of course, thanks to members here especially Greg.


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## gregzoll (Dec 25, 2006)

It was not set in "Auto" mode per chance? You also went through and set the temps, etc..


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