Unlock your LUX TX500E Programmable Thermostat

I just recently locked myself out of our LUX TX500E thermostat and couldn’t figure out how to unlock it. This created a problem because it was 95 degrees outside! And we couldn’t turn our air back on… so in a frantic I searched the internet up and down until I finally found the user manual.

For those of you who locked yourself out … the combination to unlock is > NEXT, NEXT, NEXT, HOLD

After pushing that series, voila! You should be good to go.

Another thing I found out how to do is set the programs for this thermostat. It’s a little overkill but very helpful to save some money and monitor the temperature at you house. There are two programs you are able to set > Weekday (Mon-Fri) and Weekend (Sat, Sun) To set these programs up, move the dial from Run to the ‘Set Weekend Program’ (or ‘Set Weekend Program’) and you will be able to select what temperature the house should be at during that specific time. The reason I mentioned that this is a little overkill is because you have the ability to set Morning, Day, Evening, and Night for every single day. But if you just set it for Monday, I realized that it saves for all the other days which is nice. So I just went through and selected my temps for each option.

Below is a sample of what yours might look like…

Morning (8:45 AM) 72 degrees, Day (10:00 AM – if you work during the day, you could let it go for awhile) 76 degrees, Evening (4:00 PM) 70 degrees, and Night (10:00 PM) 71 degrees.

I used to think the TX500E thermostat was hard to use, but after messing with it and actually reading some instructions it is a very helpful tool for heating and cooling your house/apartment.

94 thoughts on “Unlock your LUX TX500E Programmable Thermostat

    • Omg same problem except it is 2 Degrees outside I am in a camper, and the wind is out of the North at 6MPH, I was trying to get the heater to come on when I got home from work, then it was 11 Degrees, but I couldn’t get it to work, so I assumed I was out of LP gas.. Well I checked the furnace and found that it had a pilot light on, so I knew something else was wrong.. THe controls were not responding and there was a padlock Icon on the Screen.. That was when I realized it was the Thermostat Locked.. Searched the internet and this was the first place that came up.. THank god for that.. Phew.. I was piling blankets on me and sitting on a heating pad.. Burning Candles.. Burr So cold.. That OP is awesome and I thank him.. 44 Degrees in here now and rising..

    • OMG thank you. my daughter has a sleepover party going on and overnight the temp dropped down in the 30’s. I woke up freezing cold and just kept piling blankets on the girls while I tried to get it unlocked. I finally googled it and what a blessing. I took some blankets off the girls and honestly they probably won’t even know this happened since they were zonked out hard. Thanks again!

  1. Omg thank you! We locked ourselves out last night and it was below 0 with no heat! I froze the whole night! You are a life saver!!

  2. Thank you so much! I misplaced my manual that came with this thermostat so this was so helpful! I have printed it out and put it by my thermostat.

    • thank you for having this info on line. it was a life saver for me.
      if you can help me get a program instruction. please let me know whare I can download it.

    • I’m so glad I found your instructions but I have to say there is a couple other steps before you do the next next next hold, you first need to turn it to turn then off and then you can do the next next next hold.

    • All too often it takes “forever”to find the solution and to find a fix. This one was easy to find and the fix it worked like charm!!

  3. Just wanted to say thank you. It took me a few minutes to get this to work, because the unit was on off. In order for this to work thermostat must be ON mode. Thank you again.

  4. I just moved in to a home with the LUX X500E thermostat. It has no manual and the unlock code next,next,next,hold failed to remove lock icon on the screen. With three girls and a wife, i have no idea what happened to it, buttons frozen and A/C runniing @ 72 my only control is to turn it off. I have a flashing alert to change filter…checked it , it’s immaculate. Stumped and going broke as i type, do you have any insight as to what this is?

  5. can’t thank you enough. dont know why i didnt check the internet sooner. we were without a/c for 2 weeks in my downstairs zone. thought i had a broken fan. luckily i read your blog prior to the repair company showing up.

  6. I know this is sorta old, but thank you, thank you,THANK YOU!!!! I am house sitting for a very injured friend who is in the hospital…in Kansas, in LATE AUGUST (AKA HOTHOTHOT) and when I changed the filter, I clearly locked myself out…I was freaking out. Googled the model with “locked out”, and viola! This was a life saver!!

  7. Have been trying to figure out problem w/LUXts500E for over a month,first replaced batteries,filters,but still can’t program a/c fan and heat are flashing. Please advise what to do-61 degrees is too cold.

  8. It’s currently 5 degrees outside and I couldn’t figure out why my thermostat was dropping and not letting me change the numbers. Thank you for saving me from getting hypothermia tonight!!!

  9. Googled, “how to unlock thermostat lux.” You were third on the list and the first I chose. So simple! Thank you. Thank you. Thank you.

  10. thank you I actually liked being locked out it was set for the same temp every day so it was always 71 kept everyone from playing the up and down game with the thermostat alot but it was just too cold when the huge cold front with -30 below wind chills decided to come thru

  11. This was extremely helpful! I had a similar problem to the writer – it was going to get mighty hot if I couldn’t unlock the thermostat. And I had no idea what I did. Thanks so much for the help!

  12. Thank you for helping me out. I wasn’t in dyer need because it’s freezing here and it’s locked at 67 but I hate to leave it at 67 all day and night….gets costly. My question is how the heck does it get locked? The only thing I did was set up a weekday program and the next day it displayed the lock icon, Any ideas?

  13. Oh I can’t thank you enough…..locked myself out. Fine when it was 40 degrees out now getting into the teens. Last thing you want to do is have to tell your husband you “broke it!”

  14. You are my hero! When I typed “tx500e” into google search, the first thing it suggested was “tx500e locked”, and this was the first hit. Score 1 for the internets. Thanks!

  15. Thank you random person for posting this on the internet, because without your informative post, I’d still be locked out of my thermostat!

    House is comfy again, thanks to you.

  16. Thank you!!! 20 seconds and had it fixed and I looked like a genius!!! Much appreciation and gratitude for being precise!

  17. Oh Thank you!!!! Hubby punched a bunch of buttons and locked our thermostat not knowing how to undo it. No manual. So I googled and found your article and am SO grateful. I don’t know why the info isn’t more out there online. But thank you so much.

  18. i think the guy who put this sight up is a really good person in our eyes,maybe not so much to the heating and cooling dude we would be calling instead.But who these days can afford the H&C guy who would charge who knows how much to hit next next next hold? RIght.? you are my hero !! THANKS AGAIN YOU HAVE SAVED ME ALOT OF GRIEF AND $$$

  19. Thanks for this – even the engineer who came to verify the heater didn’t know the unlock sequence. I googled and it now works..

  20. Wow!!!!! Thanks a lot!!! I just moved in to my apartment and couldn’t get thermostat to unlock!!!! Your a blessing! !! Thank you for your info and wisdom!!!!!

  21. Thank you for the information. We were without heat all nite. Called my heating installer but didn’t know when he was coming.Looked it up and there it was, the code. thank you sooo much.

  22. Thank you. Locked out changing temp for a/c – we changed the filter and I was about to go buy a replacement. Glad I found this post.

  23. I’m hoping someone can help me. I have the LUX TX500 unit and the display screen shows OL. The N, N, N, H unlock code doesn’t work and the reset button clears everything as it should but after about 10 secs, the OL display pops up again. I’ve searched through multiple pages of Google and can’t find an answer. Any ideas?

    • I have the LUX TX500Uc and it didn’t work for me either until I set it to OFF, then RUN, and then did Next, Next, Next, Hold. Then it worked.

  24. Thank You!!! Changed my filter and somehow locked it. I’m 9 months pregnant and usu ally keep it set on 68. Woke up sweating and it was 81 in the house. Freaked out for a minute…then found this website first. Very very helpful. Don’t know how I locked it up . But glad you helped. Lol

  25. Thanks For helping me unlock my thermastat I heard what the other people were saying about the code not working , they need to turn the dial for it to work because I had to try several times turning the dial and it finally unlocked
    many thanks,

  26. OMG Thank you soooooooo very much. My daughter has a sleepover gathering an I woke up freezing cold. I guess the temp. dropped down in the 30’s, but I tried to change it an nothing. I put extra blankets on the girls and looked this up on Google. I can’t thank you enough. It was fixed in like 2 seconds. So I can remove some layers off blankets off the girls cuz this place is warming up fast. Again….Thank you!

  27. Been trying to unlock mine with no luck since July when an AC guy got it locked during a routine check. Had programmed heat and air but zero flexibility for days off like the last week!! 🙂 thank you!

  28. Thank you!!! I couldn’t figure out what the heck I did to it; as it wasn’t working anymore. Kept seeing a “lock” icon, but don’t remember locking it. I may have by mistake, but thanks to you, I was able to get my thermostat working again!!! Gracias!

  29. we are in a rental, and it got pretty cold and we couldnt figure out WHY the furnace wouldnt come on. padlock icon was on, had NO IDEA that you could even lock the thermostat. it is 321am, thank you for this information!

  30. Thank you haven’t been able to turn our heat up!!!! It has been 40in here but its steadily rising!!!! Omg life saver!!!!!

  31. Thank you so much!!! it was up to 85 in my house and I couldnt get the stupid thing unlocked. We never had a manual so I had no clue what to do!

  32. Thank you so much!
    It’s 108 outside and 88 inside, and I locked up the thermostat. You are brilliant!
    Now, can you tell me which filter it is blinking about? I replaced all of the ones in the house.

  33. Thank You. What a lifesaver. I’m in Florida, it’s August and I was having a birthday party for a 9 year old when someone locked us out after cranking it up to 88 degrees. Thank you, thank you, thank you!

  34. I couldn’t get the next, next,next, hold to work until I switched it to ‘RUN’ mode. Perfect. Also, you can pull the panel off the wall (like to change the batteries) and program it at your kitchen table or desk….

  35. Hi
    TY for the tip on override it works. My question is “the screen still says “change filter” is there any danger using the heat while “change Filter” is still flashing? BTW installed brand new filter two times, could I have installed incorrectly?

    • Not sure, could need a reset to run the diagnostics. I have since moved away from the place I lived when I wrote this post. I just leave it up because of the number of people that benefit from it. Best of luck!

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