A waste oil heater is a specialized appliance engineered to safely burn used petroleum products as fuel. This technology allows commercial and industrial facilities, such as automotive shops and manufacturing plants, to repurpose their waste oil, hydraulic fluid, or transmission fluid. Converting this waste product into heat provides an economical method for heating large spaces. These heaters are specifically designed to handle the varying consistencies and impurities found in non-standardized used oils.
How Waste Oil Heaters Ignite Fuel
Igniting thick waste oil requires specific preparation steps. Waste oil is pumped from the storage tank, filtered, and routed to the burner assembly. Because the oil is too viscous to atomize at ambient temperature, it must be pre-heated to reduce its thickness.
A thermostatically controlled electric pre-heater heats the oil to a precise temperature, typically 140 to 180 degrees Fahrenheit. This temperature reduces viscosity without causing carbonization. Once heated, a fuel pump delivers the oil to an air atomizing nozzle, which uses compressed air to shear the stream into an extremely fine mist.
This fine mist mixes with combustion air inside the blast tube. A high-voltage electric spark ignites the oil-air mixture. The resulting flame transfers intense heat to the surrounding air via a heat exchanger, and a blower circulates the warmed air into the space. Hot gases are safely vented outside through a chimney.
Approved Fuels and Preparation
Waste oil heaters are engineered to burn a variety of used petroleum-based products, allowing facilities to recycle multiple types of fluids generated on-site.
Approved Fuels
Approved fuels commonly include:
- Used motor oil
- Transmission fluid
- Hydraulic oil
- Synthetic oils
- #2 heating oil or diesel fuel
Some units can also burn used vegetable oil, although this often requires higher pre-heat temperatures to achieve proper viscosity.
Fuel Preparation and Safety
Proper fuel preparation is mandatory to ensure safe operation and longevity of the heater components. Oil must be collected in dedicated tanks to prevent cross-contamination and filtered to remove solids, metal shavings, and sludge. The storage tank should be periodically drained of accumulated water and antifreeze, as these contaminants will not ignite and can cause the system to malfunction.
Highly volatile materials must never be introduced into the fuel supply. Burning these substances creates an unsafe environment due to their low flash points, posing a significant risk of explosion within the heater. Antifreeze and chlorinated solvents are also strictly prohibited because they can damage internal components and produce hazardous emissions.
Operational Care and Maintenance
Because waste oil contains more impurities than standard heating fuel, routine cleaning and maintenance are necessary to maintain efficiency and performance. The combustion of waste oil results in a higher volume of ash and soot, which quickly accumulates on internal surfaces. Manufacturers typically recommend cleaning the unit after every 800 to 1,200 hours of operation, or at least twice during a heavy heating season.
Internal Cleaning
Maintenance involves the regular removal of ash from the heat exchanger, combustion chamber, and flue pipes, often using specialized brushes and a vacuum. The fuel delivery system requires attention to prevent clogs. This includes cleaning or replacing the canister filter, the pump head screen, and the nozzle assembly. The nozzle adapter heater block, which performs the final stage of pre-heating, must also be cleaned to remove carbon buildup that could impede fuel flow.
System Checks
Beyond internal cleaning, the chimney and venting system must be clear to handle the exhaust effectively. Facilities must verify that an adequate source of makeup air is available in the building. This prevents the system from creating negative pressure, which could draw combustion byproducts back into the heated space. Periodic inspection of safety shut-off mechanisms and seals ensures the unit operates safely and reliably.