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