The Clean Burn Model CTB-500 is the largest waste oil boiler in our product line. With an output rating of 372,000 BTU/hour, the CTB-500 is perfect for larger facilities. For operations that require more hot water output, the CTB-500 can be combined with other boilers to create a larger system. The CTB-500 is the ideal option for a business that wants to transform their waste oil into an asset that works for them.