My Honeywell pro series thermostat has a caution flag on the display. What does that mean?

Can be Low Battery Warning or Air Filter Reminder.

try:
https://www.youtube.com/watch?v=0TzL_eLXEpk

or
https://www.manualslib.com/manual/502113/Honeywell-Pro-Th3000-Series.html

Depends on what type of heat you have...gas, oil , electric, heat pump? Make sure it is the right thermostat for your heat source. Some thermostats have a switch on the back for fuel or electric.

sounds like keypad is programmed in lock position read manual for set up to activate keypad again.

Hi there..how do i change from F to C on my honeywell pro 2000 thermostat? Please help :(

installation for Honeywell TH6110 series

http://customer.honeywell.com/techlit/pdf/PackedLit/69-1920EFS.pdf

Check to see if you have power at the furnace. You thermostat is powered by 24vac coming from the furnace. You should have power on the "R" terminal.

Mike, The static electrical spark probably 'zapped' the Rth230b Honeywell Display unit. If you have already tried removing the power (batteries) from the unit and after waiting several minutes; reapply the power (batteries). If the problems remain unchanged, then it is time to replace the Display unit with a new one. The static electricity problem is problematic and the only way to prevent the same problem from recurring is to discharge yourself before touching the Honeywell Display. As you walk across the room which (probably has carpet), causes the static electricity to build up on your body and then discharges itself through the Display unit when you make contact with the Display unit. You might try coming to a complete stop and attempt to discharge the static charge on your body by touching the wall first with one hand for a second before touching the Display unit with the other hand. Naturally, cold weather with low humidity makes the static electricity worse. Hopes this helps you. Henry

If you need further help, I’m available over the phone at https://www.6ya.com/expert/henry_239f63a136de60f0

Y1 means for cool and W1 means for heat. Connect accordingly.

I just talked to Honeywell support - they claim that an eee error means there has been a "unique error" and that the unit will need to be replaced - cannot be fixed. They were pretty good about giving a suggestion for a new thermostat and wiring directions if you want to DIY. Otherwise, call a pro.