The conversion of any gas appliance to another fuel involves not only replacing the orifices (fixed and pilot), but the replacement of appliance regulators, burners and possibly the venting as well. Appliance conversions these days are not as simple and straightforward as they used to be, if the appliances can be converted at all. Historically, most all appliances could be converted from natural gas to propane and vice-versa but the gas appliances manufactured today are engineered (by professional engineers) to be used with one type of fuel as specified by the manufacturer for dedicated fuel use. In other words, most all gas appliances are built to use either propane or natural gas and are not designed to be converted or modified for use with another fuel.
· Appliance Regulator - Differences between natural gas and propane appliance regulators involve inlet and delivery pressures. The wrong type of gas appliance regulator would deliver pressure either too high or too low for the use of the appliance.