Honeywell Chronotherm III - AC

Hi there
My Honeywell Chronotherm III shows "- AC" and blinking "TEMPORARY". Any
ideas why and what can be done to fix it?
I changed the batteries - it did not help.
Thank you in advance, Alex.
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Reply to
alex4misc2
AC means there is no power to the thermostat. It could be that the circuit breaker is off or tripped, or your low voltage transformer (to your air handler, furnace, or whatever you have) is bad. Does the fan come on when you switch the fan switch from 'auto' to 'on'? If not, you have a power problem (in other words, the 'AC' does not stand for Air Conditioning).
The flashing 'temp' means that you have adjusted the temperature away from whatever you have programmed.
Reply to
Dr. Hardcrab
On 22 Apr 2008 08:25:34 GMT, alex4misc2_at_gmail_dot snipped-for-privacy@foo.com
Alex, I am somewhat of an expert on thermostats. If it is flashing "- AC" it is quite a simple fix. It just means the Air Cond will not work. Usually you just have to put in fresh batteries. If it is flashing "TEMPORARY" it just means that .....temporarily, the A/C will not work. Both messages are really working together. You often have to replace the thermostat if both messages are showing. Bubba
Reply to
Bubba
On 22 Apr 2008 08:25:34 GMT, alex4misc2_at_gmail_dot snipped-for-privacy@foo.com
Go to your local big box store and buy a can of electronspray. Carefully remove the stat and spray the red an blue wires.
Reply to
I Crack Me Up
big_dgreen had written this in response to
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: Temporary flash typically means you have a programmable t-stat and your overriding the temperature and it will reset itself back to program after about 2 hours.
AC could be a diagnostic code from the air handler to the t-stat to alert you of a problemm.
I agree with the info about possibly losing low voltage from your transformer. If the ac is not running you should call a service man.
If it is running, it may be a filter reminder, but I doubt it. I'm not familiar with the chronotherms layout.
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Reply to
big_dgreen
This is wrong! The "-AC" on the Chromotherm III display means the thermostat is not getting the 24V AC power it needs to function. It has nothing to do with Air Conditioning. (This, IMHO, is absoultely horrible product design... but that's what it is :-))
Reply to
Yer Mom
Good information, thanks. In my case, the cover on the furnace was open, so a safety interlock preventing furnace operation caused the thermostat display to essentially disappear, but it intermittently and weakly displayed the -AC code. Attaching the furnace cover solved the problem for me.
Reply to
m smith

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