for example once the audible alarm is silenced the gas powered appliance 40 may be configured to remain in a non operating condition until a qualified licensed technician inspects the source of carbon monoxide and approves the re newed operation of the unit in one implementation if the audible alarm remains silenced for a period of time e g 24 hours after the off button 26 is pushed the audible alarm may sound again after the period e g 24 hours has elapsed as a reminder an operation to sense carbon monoxide per operation 60 chart 50 b by the carbon monoxide detector system 30 may involve either or both of sensors 32 34 if carbon monoxide is not detected option 62 then the system will not take different action and the normally closed switch remains or will be maintained in a closed position flow line 70 and operation 15 a operation 15 a is either or both an initiating action to turn on the appliance and or a maintaining action or loop when in this primary implementation alternative the normally closed switch is closed and remains closed the gas powered appliance would continue its normal operation 40 a and the appliance 40 can remain on note the loop flow line 70 is figurative or schematic and need not indicate an affirmative communication during this maintaining of the operation of the appliance it may merely be that no new action takes place while there is no sufficient.