There are two main types of Heating Oil: Kerosene28 (Kero) and Gas Oil (Red Diesel). Most homes use kerosene, which is usually referred to as heating oil, or 28 second oil.
Some boilers will use gas oil, also known as red diesel or 35 second oil.
By looking at the sight gauge on the tank you should be able to determine the type of oil your system burns.
Kerosene28 is yellow and Gas Oil is a bright pinky red.
If you don't have a sight gauge, please look inside the tank or dip a garden cane inside to confirm. If you are still unsure, you should seek further advice before ordering. Your oil boiler service technician will be able to confirm this for you.
You can update kerosene 28 by adding an oil additive (premium kerosene). This additive will give you a cleaner burn, prolong the shelf life of your oil and can help to break down sludge deposits and water that naturally form in your oil tank.