To determine if a room is a limited space, add the gas inlet values of all gas appliances in the room, measured in BTUs per hour (BTU/h). (A BTU is a British unit of heat and a standard measure of the energy contained in natural gas.) You then calculate the amount of storage space for the appliance. If the room volume is less than 50 cubic feet per total inlet of 1,000 BTU/hour for gas appliances, this is a limited space and too small for the safe operation of gas appliances. The air-to-fuel ratio defines the amount of air needed to burn a particular fuel. Conventional fuels used in the combustion process are petroleum (#2, 4 and 6), diesel, gasoline, natural gas, propane and wood – ratios for regular gases, liquid and solid fuels listed in Tables 1.1 and 1.2. The size of the vents we need is a fairly simple issue because the combustion air requirements are specific and they are consistent across all the manufacturers` codes and requirements I`ve ever seen. According to Article 304 of the International Combustible Gas Code, each boiler room should have two openings, one within one foot of the floor and the other one foot from the ceiling. This should allow natural ventilation in the boiler room. Double openings also limit the possibility of a single opening being blocked and the boiler or water heater looking for air. I see many boiler rooms where the opening of the combustion air accidentally gets blocked either by leaves or garbage, or intentionally by wood or cardboard. Dear Sir or Madam, In small appliances, such as gas-fired local heaters, there is no control of the air-fuel ratio. The air/fuel ratio is adjusted at the factory to be as good as possible by manufacturers at the maximum performance of these devices. These devices have natural traction combustion chambers, without fans, to support the flow in the combustion chamber.

Thus, the resistance of the combustion chamber to the flow of air and flue gas is adjusted to maintain the optimal air-to-fuel ratio at maximum performance. However, if these devices are switched at a reduced rate, only the fuel flow will be reduced. The result is 4-5 times more air in the combustion chamber than necessary. This is an efficiency reduction of approximately 15% in the reduced tariff mode. When installing an air-to-fuel ratio control in these devices, the efficiency is 5-8% higher than the rated power. 2/3 of the annual gas consumption of these devices burns at the reduced speed when a built-in room thermostat is present. The remaining 1/3 of the annual gas consumption is burned in night light mode, the efficiency being almost equal to the efficiency measured at the reduced speed. The difference in seasonal efficiency is therefore about 20% if there is an air/fuel ratio in the heater compared to the situation in which no air/fuel ratio is integrated into the heater. It would be easy to use factory-made air/fuel devices, even in the simple gas stove: we only need a butterfly valve disc in the path of flue gases that rotates at right angles, which increases the resistance of the combustion chamber to the reduced speed of these devices to such an extent, which translates into the best air/fuel ratio even at reduced speed. The disc of the butterfly valve is located on the extended spindle of the gas valve. Thus, the gas flow and the air flow are mechanically coordinated with each other to the maximum and with the reduced performance of the device. The additional cost of such an air-to-fuel ratio device falls on the user in 0.5-1 year.

I think it`s important to let readers know what happens when there`s no air-to-fuel ratio device in a device. Their appliances that burn natural gas (usually referred to simply as “gas”) are exactly the same. They need oxygen to burn, and they get that oxygen from the air. If there is not enough air, then there is not enough oxygen – and bad things will happen. There is a balance between energy loss due to excessive air consumption and energy waste due to excessive operation in any combustion process. The best combustion efficiency occurs at the optimal air-to-fuel ratio, and its control offers the highest efficiency. A liquid and gaseous fuel burner achieves this desired equilibrium in most scenarios by working with 105% to 120% of the optimal theoretical air. For natural gas burners, the stoichiometric air required is 9.4 to 11 ft 3/1.0 ft 3 of natural gas, or about an air-to-gas ratio of about 10:1. In this case, there is an excess oxygen content of 2%.