{HEAD ~ The first four way valve} is used to direct {TAIL ~ refrigerant} periodically to flow in a series through each coil when that coil is operating as a condenser and to receive refrigerant flowing in parallel circuit when a coil is operating as an evaporator 
is used to direct
{ HEAD ~ The first four way valve } is used to direct { TAIL ~ refrigerant } periodically to flow in a series through each coil when that coil is operating as a condenser and to receive refrigerant flowing in parallel circuit when a coil is operating as an evaporator
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH