the second heat exchanger 64 in operation the system 120 conditions the air flowing from the source of air for supply of the conditioned air to the passenger compartment of the vehicle a flow direction of the air from the source of air is indicated by the arrow in the air conduit 60 similar to the operation described for the systems 10 100 the system 120 can operate in a heating mode a demisting mode and a cooling mode in a first heating mode where the engine 40 is operating and the electric motor is not operating the first heat exchanger 62 the second heat exchanger 64 and the third heat exchanger 66 transfer heat into the air stream the pump 52 of the second circuit 14 is operating to circulate the first fluid through the second conduit 38 heat is transferred into the first fluid by the engine 40 the diverter valve 48 is positioned to militate against flow through the heat exchanger 42 and permit flow through the first bypass conduit 44 thus heat is not removed from the first fluid in the heat exchanger 42 and the first fluid flows through the first bypass conduit 44 the diverter valve 50 is in a position to militate against flow of the first fluid through the second bypass conduit 46 therefore the first fluid flows through the second conduit 38 to the first heat exchanger 62 where heat is transferred from the first fluid to the air flowing in the air conduit 60 the pump 18 of the first circuit 12 is not operating to circulate the first fluid through.