... material.REFRIGERANT CIRCUITCopper tube connection with charge valves, filter, thermostatic expansion valve (capillary for mod. 4.5-14), gas-liquid separator, ... heat pump units are complete also with 4-way valve and one way valve.HYDRAULIC CIRCUIT Built with user side and source ... discharge connectors, air vent valve, mod.4.5-30 the user side is complete also with expansion vessel, water pump and ...