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 {HEAD ~ the outlet} of one coil used as {TAIL ~ a condenser} to the expansion means of the other coil used as 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 { HEAD ~ the outlet } of one coil used as { TAIL ~ a condenser } to the expansion means of the other coil used as an evaporator
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