dc was on the net, so I tested out the deicing control script. Seems to be working, and even found conditions (ldiag nonzero and temp below 1º) that trigger deicing. I installed it in the crontab to check conditions and run if needed every hour. There's a log of the relay on/off state in CFACT/ISFS/logs/csat_heat.log, and there's a nidas watched file sensor for it that will record the heater state (sample id 6).

I'll check tomorrow to see how it does running overnight.