Question about Honeywell Programmable Thermostat Heater

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Battery backup? I have a programmable Honeywell Thermostat T8000C or T8001C or T8011R. The thermostat has been working fine EXCEPT when I've lost power. I think there must be a battery backup to keep the time because the past month we've lost power twice and the thermostat gets completely lost and I have to reset the time. I've lived in this house for four years and not had this problem in the past. Is there an online site that will show me how to pull the cover off to find the battery? Also, do you know what battery I need to buy?

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  • MaurBig Mar 08, 2008

    Thanks. I managed to get it off the wall and was able to establish that it didn't have a battery. I have an all electric system with a heat pump and emergency furnace. I think I have the 8011 (I figured it out in January but don't remember for sure).



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Which model do you have ? the 8000/8001 or 8011 the set is different depending on your type of heating system. This model has a memory chip not a battery that saves your settings. So you could be looking at replacing the unit.

Posted on Mar 08, 2008

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How do I change the battery on t800lc

Posted on Jul 19, 2011


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To 'Guest' , enter your 68 degrees at WAKE, LEAVE and RETURN, then enter 66 degrees at SLEEP. Do this for the Monday through Friday time frame and again for the Saturday - Sunday time frame.

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