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Question what does -AC mean on my thermostat screen it keeps popping up and can't get unit to come on leo

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A programable thermastst has different modes. in auto it can deside whether to apply heat or cooling. ac air coditioning. or you are in ac mode, but should notice the ac unit comming on. if no ac unit then of corese it won't come on :)

Posted on Feb 04, 2008

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What does -AC on honeywell chronotherm III thermostat mean?

AC means "air conditioning." If the AC icon is showing on your thermostat it means that your air conditioning is activated and should come on when the temperature threshold you've set on the thermostat is reached.

For example, if you've set the temperature level to 78 degrees, when the house temperature goes above 78, usually by about two degrees, the air conditioner should cycle on to cool it back down to 78 degrees at which point it will then turn off.

This information should be in your air conditioning/heating system or thermostat owners manual. If you don't have the manual, you should contact your air conditioning dealer or your builder to secure a replacement. The manual is essential for proper operation and maintenance of your system.

May 14, 2014 | Thermostats

2 Answers

The unit keeps flashing

By unit, do you mean the thermostat? And if so, do you mean the whole face is flashing, or just a heat or cool symbol? And if your talking about the heating/cooling unit, are you talking about a flash on the board?
A thermostat face that is flashing is usually batteries.
A symbol that is flashing on a thermostat indicates a call and is in a delay. There will be a 5 minute delay on calls if the call has been short cycled, powered off and on, etc.
If the symbol continues to flash for an extended amount of time, then the problem is in the furnace, air handler, etc.
If the system is working, but flashing, then it could be the programming of the thermostat.

Dec 02, 2013 | Honeywell Thermostats

1 Answer

I have a Honeywell A/C Unit, it's about 17 years old. The contactor melted so I replaced it with the exact one. Now the inside thermostat will not turn on(in cool or heat position) so I replaced that too...

See if there's any 24 volt control voltage. You can check it at the thermostat using a voltmeter set to ac. measure across the red wire and the common terminal. No 24 volts means a new transformer.

Aug 15, 2013 | Honeywell Programmable Thermostat Heater

2 Answers

The transformer on my central AC/heater (luxaire model # A236A344T LH) keeps going out. There are 4 settings on the wall. Cool, off, heat and EM. Heat. The setting switches to EM. Heat each time the...

You might have some thermostat wires that are touching meaning the insulation has been broke off and getting a direct short. Check the wiring going to the outside unit and replace any wire that is in bad shape. let me know okay. Ken

Dec 11, 2009 | Honeywell Programmable Thermostat Heater

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Thermostat not functioning correctly

-AC means there is no power coming from the furnace. not a tstat problem

Sep 24, 2009 | Honeywell Programmable Thermostat Heater

1 Answer

Problem with my Airtron Thermostat

Two things, first go up to the heater and check the fuse inside the heater, looks like a car fuse. If that is not popped, then go outside to your AC unit and pull out the emergency disconnect. Check those fuses with a multimeter. IF you do not get anything replace those fuses, It has nothing at all to do with your thermostat.

Feb 09, 2009 | Honeywell Programmable Thermostat Heater

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Chronotherm III Thermostat Completely Blank Screen, No Heat

One of two things either the disply has gone out which is likely as it is a common failure for that thermostat or your heating unit is not sending control power. the older chronotherms were system (24volt ac) powered the new hardware/box store units are battery powered. Either way display should not be blank with fresh batteries. to get heat on remove the thermostat jumper or twist together the wire from the R terminal with the wire from the W terminal. note the color of each wire for later reference, heat up house disconnect wires from each other and go purchase a new thermostat

Dec 17, 2008 | Honeywell Programmable Thermostat Heater

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