... . Then “please open earthing switch” will be warned ² Even two wrong situation happen, then operator will be reminded ,“Please open ... switch”-Temperature & humidity display and Control² Model SGC-03T has two way T/H controller inside. Start up heater while RH≥90 ... RH≤95%-Withstand Level≥ 2000Vac,Insulation Level≥100MΩ -Two way T/H controller -Two way loads output for heater, or fan or overheating alarm ...