A burner unit , comprising: a first set of burner assemblies (BA1); a second set of burner assemblies (BA2) surrounding the first set of burner assemblies (BA1); first and second valves fluidly coupled to the first set of burner assemblies (BA1); a first valve control assembly (VCA1) configured to control the first and second valves of the first set of burner assemblies (BA1) between open and closed positions; third and fourth valves fluidly coupled to the second set of burner assemblies (BA2); and a second valve control assembly (VCA2) configured to control the third and fourth valves of the second set of burner assemblies (BA2) between open and closed positions, the first and second valve control assemblies (VCA1, VCA2) being separate assemblies, wherein the first set of burner assemblies (BA1) includes a first burner assembly having a first flame crown and a second burner assembly having a second flame crown , wherein the second set of burner assemblies (BA2) includes a third burner assembly having a third flame crown and a fourth burner assembly having a fourth flame crown , wherein the first and second flame crowns are circular flame crowns that are concentric with one another, further wherein the second flame crown is disposed around the first flame crown , wherein the third flame crown is a circular flame crown that is concentric with the first and second flame crowns , and further wherein the third flame crown is disposed around the second flame crown , wherein the fourth burner assembly includes first and second lobes outwardly extending from the third burner assembly on opposite sides thereof. a first set of burner assemblies (BA1); a second set of burner assemblies (BA2) surrounding the first set of burner assemblies (BA1); first and second valves fluidly coupled to the first set of burner assemblies (BA1); a first valve control assembly (VCA1) configured to control the first and second valves of the first set of burner assemblies (BA1) between open and closed positions; third and fourth valves fluidly coupled to the second set of burner assemblies (BA2); and a second valve control assembly (VCA2) configured to control the third and fourth valves of the second set of burner assemblies (BA2) between open and closed positions, the first and second valve control assemblies (VCA1, VCA2) being separate assemblies, wherein the first set of burner assemblies (BA1) includes a first burner assembly having a first flame crown and a second burner assembly having a second flame crown , wherein the second set of burner assemblies (BA2) includes a third burner assembly having a third flame crown and a fourth burner assembly having a fourth flame crown , wherein the first and second flame crowns are circular flame crowns that are concentric with one another, further wherein the second flame crown is disposed around the first flame crown , wherein the third flame crown is a circular flame crown that is concentric with the first and second flame crowns , and further wherein the third flame crown is disposed around the second flame crown , wherein the fourth burner assembly includes first and second lobes outwardly extending from the third burner assembly on opposite sides thereof. <EOS>