control means for controlling, in {HEAD ~ dependence} upon {TAIL ~ an operating load} of said boiler means, at least one of a flow rate of said combustion air into said boiler means, and an operating pressure in said combustion chamber of said boiler means, and 
upon
control means for controlling , in { HEAD ~ dependence } upon { TAIL ~ an operating load } of said boiler means , at least one of a flow rate of said combustion air into said boiler means , and an operating pressure in said combustion chamber of said boiler means , and
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH