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