Refer to the Table below for a general description of the thermostat. The T8601D2019 thermostats require a common wire (C terminal) to be connected to the low voltage power transformer. Nice! These Chronotherm IV thermostats are "The pick of the litter".

• Programmable fan operation even during times when the rest of the system is off.
• Works well on gas, oil, electric, radiant floor heat, water system, and even on heat pumps.
Can automatically change the system to heating or cooling or may be operated in manual changeover mode.
• Has numerous installer setup options:
• Heat pump or electric heat applications where thermostat controls fan operation in heat mode.
• You can choose the number of operations per hour the system can run to better maintain the correct temperature.
• Configure auto changeover or fixed auto changeover.
• Conventional recovery (system starts recovery at programmed time).
• Configure Celsius or Fahrenheit temperature display.
• Display 12 or 24 hour clock.
• Fan operation can be extended 90 seconds after the call for heat ends.
• Fan operation can be extended 90 seconds after the call for cool ends.
• Outdoor temperature display can be chosen or not displayed.
• Heating and cooling setpoints can be allowed to be closer or kept farther apart.
• 2°F (1°C) apart
• 4°F (2°C)    "
• 5°F (2.5°C) "
• 6°F (3°C)    "
• 7°F (3.5°C) "
• 8°F (4°C)    "
• 9°F (4.5°C) "
• 10°F (5°C)  "
• Minimum number of minutes (0 thru 5) the compressor will be off between calls for the compressor can be set.
• You can configure the thermostat so the heat can be no higher than a specified temperature (selectable in one degree increments from 40 to 89°F).
• You can configure the thermostat so the cooling can be no lower than a specified temperature (selectable in one degree increments from 46 to 99°F).
• The temperature display can be set 3°F above or below the actual room temperature.
• Programmable for each of the seven days of the week with four times and temperatures selectable for each day or night.
• Thermostat has available a self-test to check the thermostat operation:
• Heating equipment can be turned on and off.
• Cooling equipment can be turned on and off.
• Fan equipment can be turned on and off.
• Keyboard keys test. Here is a picture of one of the tests where all of the available thermostat functions are displayed at once:

• Thermostat information including date code and software versions are displayed.