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Removing old lennox thermostat

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21K views 19 replies 6 participants last post by  Master of Cold  
#1 ·
I bought a digital thermostat but am stumped as to how to remove the old lennox stat. Only numbers are inside: 9549 E8. There are no screws visible and if I pry from behind, or in between the base layers, I feel like I'll break it. Thanks.
 

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#3 ·
Turn the breaker to the furnace off before removing any wires. Whichever wire is on RH or RC terminal will be hot, 24 volts. If that wire touches anything while live you stand the chance of blowing the fuse on furnace board. Just a minor inconvenience but still more work than neccassary if it blows.

Under those three screws there'll be two more holding that base to the wall.
 
#6 ·
You're welcome!

Thank you for letting us know how things worked out for you. :)

I hope the new thermostat is everything you hoped it would be.
 
#7 ·
Actually, I think I'm gonna put on the old mercury based lennox. This thing (honeywell) stinks. It seems like it runs the ac forever. I guess cause its trying to get the temp down a full degree below the setting or something. Anyhow...we never felt so cold or so hot with the old thermostat. Thought this would be better for a newborn.
 
#10 ·
RTH2310 Programmable Thermostat. It was $50 at Walmart but with a $25 rebate so I guess it is a cheapo. Doesn't look like there is any adjustment/setting for this (ie- change when it turns on or turns off in relation to thd temperature setting. For example, if I set it at 72, it seems to want to take the room temp to 71 before shutting off. likewise it seems like it won't turn on until it gets to 74. I'd rather it shut off at 72, and turn on at 73).
 
#13 ·
So am I looking for something with a "high/low" setting or "setpoint/desired temp" setting? (I saw those phrases in the specs on some of the higher end honeywells I googled). I want the ability to tell it when to kick on and off in relation to the temp I set zbd just need to know the proper "lingo" to look for. Thanks a lot guys. I'll bd taking this off soon.
 
#17 ·
I'm no hoax expert, but I don't think what I'm looking got is as complicated as "two stages of aux heat". Merely a setting that says: "shut off the ac when the temp reaches the temperature that is set, and turn on when the temp goes only one degree above that setting" (rather than turning off the ac when the room temp reaches a full degree BELOW the set temp, and turning on when the room temp gets 2 or 3 degrees above that setting). I'd just rather the ac come on more frequently for shorter amounts if time. If that requires "two stage" something or other then I'm totally lost. Thanks.