I have a Honeywell Chronotherm 3 thermostat (T8602) that is giving me
trouble. I use to override the WAKE, SLEEP, etc. settings and use the
thermostat manually by pressing the up or down arrows to get to the
temp I wanted and then press the hold button. Worked great. Can't do
that anymore. When I set it to the temp I want, the furnace will come
on for a few minutes and then stop. Then the thermostat makes a
clicking noise for about 30 seconds. The batteries are fresh. The
thermostat is about 20 years old. Any help would be appreciated.
Thanks.