These openings 518 allow a cooling medium to flow through the passage 516, which assists in removing {HEAD ~ heat} from {TAIL ~ the coils} 306 a,b 
These openings 518 allow a cooling medium to flow through the passage 516 , which assists in removing { HEAD ~ heat } from { TAIL ~ the coils } 306 a , b
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH