Before you install your heater cartridge, you should double check that you both purchased and received the correct voltage cartridge. Cartridges are laser etched with their voltage, but all it is worth double-checking anyway. This process is less annoying than putting out a house fire.



If you have a 12v30w heater cartridge, your multimeter should read 4.8Ω    


If you have a 24v30w heater cartridge, your multimeter should read 19.2Ω


If you have a 24v40w heater cartridge, your multimeter should read 14.4Ω