I have setup a SPM_OAReset which does not quite work as expected. At Outdoor air temperatures less than -10 oC the Outdoor Low Setpoint temperature is not respected, as seen in the air inlet node temperature.
Ha! I solved my problem just after posting
There’s an input to the Htn Couil, which specifies the min outdoor temperature for the compressor operation. This is set to -8 oC per default.