carrier freeze protection fault

Hi All,

I have a carrier twin screw aircooled chiller that keep failing on freeze protection at night when it has no run command.

Any ideas of what could cause this fault?

What is the nighttime ambient temperature?

Have you checked the setting/operation of the fluid low temperature switch?

Are the pumps running at night

the night ambients are always above 0 degrees and the problem happens all year round when the overnight temp would be above 10 degrees

the chiller has onboard pumps so I dont think they run at night.
I removed the plug for remote running of the chiller so it did not get a call to run from anywhere.

Chiller must have "black box" in its controller. can u check data at moment of fault?