I'm looking to replace my Honeywell Chronotherm III T8600c1014 7 day programmable thermostat with another 7 day programmable thermostat useing the same wireing W G R Rc Y is there a few thermostats I can choose from? Thanks Tony

PDF]Chronotherm III 7 Day Programmable Thermostat - Honeywell

https://customer.honeywell.com/resources/techlit/.../69.../69-0352.pdf
O I" O 0. HEAT M10 COOL OF ow to operateyo. This Owner's Guide will show you how to get the most benefit from your new thermostat. Your new Honeywell ...

Here's a manual for your unit. https://customer.honeywell.com/resources/techlit/TechLitDocuments/69-0000s/69-0690.pdf Here's another link to trouble shoot your problem. http://archives.hvacmechanic.com/archives/228

Hello,Message AC means that there is no 24volt power to the thermostat from the unit/s it controls.Please check all switches & curcit breakers to the unit/s as there is no low voltage power to the thremostat from the transformer in the unit/s.Maybe got turned off by mistake.

No. The clock is just the set back timer. Pull the battery and use the stat manually.

If it is just a heater,it means no power.

you are not geting AC power from the furnace

sounds like t-stat is going bad

Hi, your replacement part can be purchased on amazon, take a look here: Amazon com honeywell chronotherm III thermostat. I hope this was helpful. Cheers

change the batts on the stat