Apparatus controlling a plurality of {HEAD ~ fuels} of {TAIL ~ different heat contents} to a fluid heater burner including valves for selectively connecting the fuels to the burner and pressure responsive fuel flow regulators responding to the combined fuel/air pressure at the fuel burner to provide a given level of output for the boiler 
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Apparatus controlling a plurality of { HEAD ~ fuels } of { TAIL ~ different heat contents } to a fluid heater burner including valves for selectively connecting the fuels to the burner and pressure responsive fuel flow regulators responding to the combined fuel / air pressure at the fuel burner to provide a given level of output for the boiler
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 OTH OTH OTH OTH OTH OTH OTH OTH