A second four way reversing valve is provided in the refrigerant circuit between outlets of indoor and outdoor coils to direct refrigerant through liquid lines of the refrigerant circuit from the outlet of one coil used as a condenser to the expansion means of {HEAD ~ the other coil} used as {TAIL ~ an evaporator} 
A second four way reversing valve is provided in the refrigerant circuit between outlets of indoor and outdoor coils to direct refrigerant through liquid lines of the refrigerant circuit from the outlet of one coil used as a condenser to the expansion means of { HEAD ~ the other coil } used as { TAIL ~ an evaporator }
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