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