We changed our old honeywell thermostat (with mercury) to an updated honeywell thermostat (with no mercury) CT87K. After we changed the thermostat the furnace will not automatically kick on and it actually shut off so we had to hit the reset button.
The furnace at times now will turn of if we put the desired temperature to 70 even though the temperature in the home is 66.
What did we do wrong here? Thank you.:confused:

Did you pick the correct fuel as it states on page 4
Did you set the cycle switch as it states to do on page 4
Did you transfer the wiring to the exact place for place that it says to do.
IE w to white etc.

Read the below manual to see how all the above is supposed to be done.