We have a large patenting furnace with air/gas pre mix burners, 4 zones in furnace with about 10 burners per zone. By design from standards above, can it be possible that if 1 burner in a zone fails, it can be switched out of the group electrically but the gas/air mix to the burner is a manually operated valve which can be left open, this allowing the remaining burners to light and run with the dangerous situation of the gas/mix from the locked out burner to enter the furnace?