What is the difference between high altitude natural gas burner and conventional low altitude gas burner and why high altitude natural gas burner are needed?
The basic chemistry of efficient natural gas burning is about a 10:1 air to fuel ratio. The air at high altitudes has less oxygen per volume (the air is less dense)
There are a number of ways to compensate.
- Derate the burner by decreasing the fuel orifice size. This returns the burner to the correct air-fuel ratio, but produces less heat. This method is going out of favor in higher efficiency appliances.
- Add air to the natural gas. You are in effect derating the gas content to get the proper air-fuel ratio. This is done at the utility, your appliance vendor will know what percentage is added (if any) in your area.
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The assumed need for a high altitude burner or orifice is based on the fallacy that while air gets thinner at high elevation, gas does not. Go back to the gas laws and use absolute pressure not gauge pressure to see how natural gas or propane gets thinner at very close to the same rate as air. Jan 24 '16 at 14:21
In order to produce the maximum amout of heat the natural gas and air are mixed at precise ratios. Because the amount of oxygen in a given volume of air varies with altitude, air at high altitiude doesn't contain enough oxygen for an efficient mixture. .High altitude burners allow more air to mix with the gas to maintain optimal fuel/air ratios.
