What happens when a system designed for natural gas is supplied with propane gas?

When a system designed for natural gas is supplied with propane gas, the correct answer reflects that the flame will be too high unless modifications are made, specifically, installing a smaller orifice. This is because propane has a higher energy content than natural gas, meaning it releases more heat per unit of gas burned.

If a system set up for natural gas operates with propane without any adjustments, the result is an excess of fuel being supplied relative to the amount of air available for combustion. This imbalance causes a flame that is higher and can lead to dangerous conditions including overheating and potential damage to the appliance itself. Adjusting the orifice size ensures that the correct fuel-to-air ratio is maintained, allowing for safe and efficient operation of the system with propane.

In contrast, if one were to incorrectly choose an option that suggests no changes are needed, it would ignore the fundamental differences in combustion properties between the two gases, particularly their required air-to-fuel ratios. Similarly, suggesting that the flame would be too low unless a larger orifice is installed would misconstrue how propane burns compared to natural gas. Lastly, while alterations to the gas regulator and valves can sometimes be necessary in certain systems, the immediate and most critical adjustment relates specifically to the orifice size