Subsequently the heater is turned off and {TAIL ~ the chamber} is cooled by {HEAD ~ a fan} 
Subsequently the heater is turned off and { TAIL ~ the chamber } is cooled by { HEAD ~ a fan }
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD