Minimum Outdoor Temperature to use Cooling

Most air conditioners are not meant to be run when the outdoor temperature is below 60 degrees as it can harm the appliance and shorten its life. In the variable climate I live in (Minnesota) its really easy to see outdoor temperature ranges of up to 70 degrees (F) in any given week, and sometimes days in the spring or fall. This means that I have to manually check every day (and/or night) to make sure I have my scheduling set up so that my A/C will not run if it is too cold outside.

The idea here would be to add a toggle to the thermostat advanced settings called “Cooling Protection” and allow the user to specify the minimum outdoor temperature that the Cooling can run. If the toggle is turned on, the thermostat will query some kind of weather API based on its location to know whether or not to turn on the A/C based on the user’s “Cooling Protection” setting value.

As a professional control system engineer, I absolutely agree with singerbj here! A simple software feature, whose setting could be adjusted in the app, can save your customer from condensing unit damage.

This is standard practice on commercial air conditioning projects. Sometimes, the condensing unit has an ambient temperature interlock to protect the compressor from trying to compress liquid refrigerant (liquid does not compress!), and sometimes it does not. It is standard practice to include that interlock in control system programming, whether the condensing unit has that feature or not, as we cannot count on the built-in interlock not being misadjusted at some point in the future.

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