... gage, compressor inside the indoor unit 2.auxiliary heater for option, you can choose from 1.5Kw~7.5Kw3. ... heater also work during defrosting, our PCB with the control of the auxiliary heater, that is as a electric boiler, ... efficiently even in the harsh environment – 25°C, double high-efficient heating and cooling.Advanced control, easy operationMicrocomputer intelligent control, any terminal ...