7-day program w/ 4 periods/day, 3 configurable
outputs, adjustable dead bands, control to or monitor a sensor,
when outdoor sensor is used max/min daily temps are recorded,
smart recovery, programmable fan, vacation/holiday mode, accepts
modules for internet or phone control. built-in humidify/dehumidify module, programmable
output, dual fuel control, advanced heat pump operation, dry
contact, averaging of remote sensors, filter alert ready,
drainpan overflow alert ready, reheat capable, energy watch,
accepts modules for internet or phone control.
of Jan 2022, the new model is T3900 and the pin locations are now
different than the original, so the new baseplate will need to be
installed so that the wiring and pins match up correctly. It is no
longer possible to just pull the front of the thermostat off and replace
it while leaving the baseplate wired to the wall. Only compatible with 2-wire remote sensors, NOT the 3-wire RS+5/RS1/RSGND versions.