Many kerosene heater manufacturers, such as Toyotomi or DuraHeat, make the user manuals for their products available for free on their websites. It is also possible to find free user manuals on a website of a kerosene heater distributor, such as Kerosene-Wicks.com.
To find the correct manual, it is important to correctly identify the model and type of the heater. Most heaters have their model name visible on the front side. Usually, there is a serial number on the reverse side of the heater. The last letter of the serial number represents the type of the heater. It's important to read the manual before using the heater, as incorrect use may cause safety hazards.