Can I use natural gas orifice for propane?
Regarding this, can natural gas appliances run on propane?
Yes, propane appliances can run on natural gas, but it is not advisable without installing a conversion kit.
Keeping this in view, what is the difference between a natural gas orifice and a propane orifice?
Natural gas is fed at a smaller pressure than propane, so to get the same heating value (usually measured in BTUs), a natural gas orifice has to be smaller than a propane one. This suggests that you can convert a natural gas appliance to a propane one and vice versa by changing the orifice on the gas valve.
In other words, connecting a natural gas appliance to a propane piping system will result in appliance malfunction and possibly danger. The reason for this is because natural gas orifices are larger than propane orifices strictly because of gas service pressure.