{TAIL ~ The heat pump} in accordance 1 or 2, wherein said {HEAD ~ second reversing means} is a four way valve 
{ TAIL ~ The heat pump } in accordance 1 or 2 , wherein said { HEAD ~ second reversing means } is a four way valve
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH