# Thermostat or furnace problem?



## dakuda (Feb 11, 2008)

My first though is my thermostat.....

My thermostat (Lux TX9000a) and furnace seem to work fine when they are on the program that I set.  However, when I turn up the temperature to override the program, I start to have issues.  

My thermostat will flash the word 'Heat' while the furnace is running.  Oftentimes, the word will be flashing, while the temperature drops 10+ degrees with no activity from the furnace.  Most of the time, this is when I am sleeping.  If I manually turn the temperature down below the current temp, then back up, it seems to kick back on.

So, any guesses on this being a thermostat problem?  I don't feel like spending the $ on a new thermostat (the current one is from Aug 06) if it wil' be wasted...


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## CraigFL (Feb 11, 2008)

It sounds like you're saying it worked fine for over a year and now it's not always turning the heat on when you demand it. The first thing I would do is a thermostat reset(like a reboot). You may have to reprogram it after you do this. Look in your owners manual to find the reset switch-- usually a pushbutton accessed thru a small hole.


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## AU_Prospector (Feb 11, 2008)

Change the batteries?

Sorry to state the obvious, but I had an electronic programmable thermostat which was fairly new like yours and had similar symptoms last fall at the beginning of the heating season at my previous home.  My thermostat had 2 AA batteries in it.  When I replaced the batteries, the symptoms went away. 

Just a thought
Prospector


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## dakuda (Feb 21, 2008)

I replaced the batteries last month when all of this started.  I also hit reset and reprogrammed the whole thing.

I called Lux and they sent me a new one since the first post.  The same problem is still occurring.  If I jump the power for the furnace, it runs fine though.  I am confuzzled.


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## triple D (Feb 21, 2008)

Let me see if I have this right. When you have the heat set to maintain room temp it operates fine, but when you run program you end up with troubles of dropping temp? Is the furnace blowing or not when tstat is flashing heat? Does this anomaly happen during the day or just at night. And has this never happened up till a month ago? Is it a two wire system? Talk to ya soon....


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## dakuda (Feb 29, 2008)

There are four wires in the thermostat.  

You have it backwards -- it works fine while on the program and doesn't work while off the program.  If I run it up to 70 and press hold, the problem starts.  It is mostly at night, but that is pretty much the only time I override the program.  People don't visit me when I am at work, I hope.  THis is a fairly new problem.  Last winter I never had this problem.


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## Damon (May 14, 2008)

To check the thermostat, go to the furnace and locate the low voltage connections from the thermostat.  When you override the program to force heat, you should have 24V from the white wire (or W terminal) to the Common (C terminal). If not, the Tstat is not calling for heat.


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## johnhumid (Sep 6, 2009)

I guess the first thing you might do is to reset the thermostat and if it goes nothing then you might check the furnace and the low voltage connections...



_________________
Humidifier filters


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## philfrigo (Jan 2, 2010)

My tx9000a thermostat shows a little "Paddle-lock" icon and will not allow manual over-ride. The thing is stuck at 62 degrees.


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