Problem with the upper and lower thermostats 1. lower thermostat gave
E74 this morning (no power to Rh wire) now the temperature is 54
downstairs 2. upper thermostat since morning shows temperature is at 66
when the set temp is 76. Keeps showing the ...
Nest learning thermostat the problem has been fixed. It turned out that
the humidifier plastic pipe that was draining outside was frozen. The
ice in it triggered a safety lock on the furnace and prevented it from
restarting, giving the no power to Rh...