... ,domestic hot water Monoblock EVI air to water heat pump:1. indoor unit included 4 way valve, liquid storage tank, pcb, ... exchanger, auxiliary heater, pressure gage, compressor inside the indoor unit 2.auxiliary heater for option, you can choose from 1 ... convenient useUltra-thin auxiliary unit design indoor,sharp appearance, compact structure, hidding in the room completely. Water pump and flow switch ...