Auto-settings for thermostat work fine for AC but not for heater?
The auto setting on the thermostat for our 2-story home works fine for air-conditioning but shuts off prematurely when controlling the heater. It never stays on until it reaches the preset temperature, but instead shuts off by itself, requiring us to
It may be the thermostat. Today there is a vast array of T-stats on the market, and not all of them are made for the same applications. There really isn't enough information from you to provide a good guess as to what may be the problem.
