What temperature ranges are acceptable for heating and cooling?
Heat settings should be between 40°F to 90°F (4.5°C to 32°C), and Cool settings should be between 50°F to 99°F (10°C to 37°C). If temperature settings do not change, verify they are within these acceptable ranges.
From the official Honeywell TH3000 Programmable Thermostat manual, page 13
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