What is the minimum outdoor temperature for safe air conditioning operation?
Do not operate the cooling system when the outdoor temperature is below 50°F (10°C). Operating below this temperature can cause possible compressor damage. This is an important safety caution to prevent equipment damage.
From the official Honeywell T6220D Programmable Thermostat manual, page 3
Have a follow-up question?
Answers from the official manual.
Common questions