what causes carbon monoxide to start coming out of a gas fire?

Answer 1

Since you posted this in Chemistry I assume you need a chemistry type answer. So:

CH4 = natural gas

CH4 + 2O2 => CO2 + 2H20
(in well ventilated conditions and with a properly functioning flue)

2CH4 + 3O2 => 2CO + 4H20
(in poorly ventilated conditions or with a blocked flue)

Answer 2

Carbon monoxide comes out of gasoline fire, or any kind of fire except hydrogen for that matter, because most flammable materials contain carbon in them. Oxygen from the surrounding air combines with these carbons and they break off as CO (carbon monoxide) and CO2 (carbon dioxide). This process also creates heat and water vapor.

Answer 3

Poor combustion due to fouled up or damaged burners, blocked or partly blocked air intake or flue gas outlet to or in the chimney.
If you have Carbon Monoxide coming from the gas fire, it's deadly poison and often not noticed until too late.
Under any circumstances, DON'T USE IT and get it checked out and maintenance carried out as soon as possible.

Answer 4

the process of combustion produces carbon monoxide. All such appliance (like a water heater) should have an exhaust and for safety, put up a carbon monoxide detector in your house.

Answer 5

Incomplete combustion of carbon

Answer 6

I agree with others Incomplete Combustion.

Answer 7

Incomplete combustion.

Answer 8

Incomplete (lack of oxygen) combustion

Answer 9

If there is not enough oxygen to make carbon dioxide from all the C atoms in the fuel.

Answer 10

incomplete combustion caused by a lack of oxygen.