Helical Coil Hot Oil Heaters

CEI Helical Coil Hot Oil Heater

Hot oil heaters, also referred to as thermal fluid heaters, or thermal oil heaters, heat thermal fluid that is engineered for heat transfer applications. Thermal fluid heaters are safer and easier to maintain than boilers. The heated thermal fluid exits the hot oil heater and is circulated through heat transfer piping, transferring heat to end user equipment such as asphalt storage tanks at asphalt plants or at bulk liquid storage terminals. The thermal fluid then returns to the heater, completing the hot oil circuit.

CEI Helical Coil Hot Oil Heaters are available in two basic configurations: HCS-series for single hot oil circuits, and HC-series for multiple hot oil circuits. Four standard models are available in each series, with outputs from 1.2 million to 4 million Btu/hour. All heaters can be customized to meet your specific needs.

Single Circuit Systems:

Small plants with only one or two liquid asphalt tanks usually need only one hot oil circuit with one pump. HCS-series heaters are well-suited for such plants. One circulating pump, mounted on the heater skid, circulates the heat transfer oil through the heater and through heated plant components.

Multiple Circuit Systems:

Plants with storage silos, multiple asphalt tanks, and additional components can usually benefit from using multiple hot oil circuits.

HC-series heaters are designed for such applications. They feature a manifold on the output connection that supplies oil to multiple additional pumps. Each of these side pumps is dedicated to an independent hot oil circuit.

Using multiple circuits reduces the load on each pump, its motor, and its operating pressure. This system is much more flexible than a single-circuit system because each circuit can be operated independently.

Operation & Features

CEI Helical Coil Heater Operation

Centrifugal Circulating Pump:

The centrifugal circulating pump, mounted on the heater skid, circulates heat transfer oil through the heater. Viton shaft seal rings provide a reliable seal with virtually no leakage.

If the heater is equipped with an optional stack heat exchanger, the oil first enters the exchanger, where it is heated by hot exhaust gases. Oil then exits the stack heat exchanger and enters the helical coil, where it is heated by hot gases from the burner.

Full-Modulation Burner:

The full-modulation burner conserves fuel, reduces temperature overshooting and eliminates constant on-off burner recycling.

The burner fires into the open center of the helical coil, creating the first pass of hot burner gases. Burner gases then turn at the end of the coil, making a second pass along the coil’s outer surface.

Helical Coil:

The helical coil is designed and built to ASME code. It is designed to provide a large heat transfer surface area, low flux rates, and an ideal fluid velocity of 7 to 11 feet per second. ASME stamp is available as an option.

Stack Heat Exchanger:

The stack heat exchanger is an available option that can boost the heater’s thermal efficiency by 5%. Hot burner gases exiting the heater pass around a densely packed set of serrated finned tubes inside the heat exchanger. Thermal oil flowing inside the tubes is heated before entering the helical coil.

This option reduces fuel usage by reducing the output demand placed on the burner. This can reduce fuel consumption by 261 gallons of No.2 fuel oil or 345 therms of natural gas per month. A stack heat exchanger usually pays for itself in one year, or less.

UL-rated, NEMA 4 Control Panel:

The UL-rated, NEMA 4 control panel is the nerve center of the heater’s temperature control and safety systems. Compliance to UL standards not only assures you of the quality of the electrical system, it also puts your insurance company at ease, potentially bringing you lower premiums. The NEMA 4 enclosure provides watertight protection against splashing water, hose-directed water, rain, sleet, snow, ice, dirt, and windblown dust.

Panels that meet CSA specifications, and other NEMA standard enclosures are available optionally.

Temperature Controllers:

Two microprocessor-based controllers provide control over output temperatures. The Temperature Controller regulates the flow of fuel and combustion air to the burner to efficiently maintain the temperature set point on the controller.

The High Media Controller is a safety control. It will shut down the burner if the heat transfer oil reaches the temperature limit set on this controller.

Flame Monitor:

The flame monitor is a microprocessor-based burner management control system. The monitor provides proper burner sequencing, ignition and flame monitoring protection. In conjunction with limit and operating controls it sequences the burner/blower motor, ignition, and fuel valves to provide for proper and safe burner operation. Other features include:

  • Self-diagnostic for safety and reliability.
  • Non-volatile memory retains information even when power is interrupted.
  • Microprocessor-based for accurate timing, comprehensive diagnostics and precision control.

Digital Annunciator:

The digital annunciator visible on the front of the control panel displays heater status at all times. Any safety limit that is exceeded will immediately shut down the burner. The cause will be clearly displayed on the LCD screen, reducing down time and assisting CEI Service personnel diagnose any heater issues remotely, if necessary.

Wireless Monitoring Systems:

Wireless monitoring systems are optionally available for additional convenience and reduced down time. These systems communicate any heater shut-down issues to your cell phone, so you will know what’s happening with your heater, no matter where you are.


The heaters operate on natural gas, LPG, or No. 2 commercial grade fuel oil, depending on the burner used. An optional combination burner allows switching between two different fuels.

Thermal Efficiency:

Aside from safety and reliability, thermal efficiency is probably the most important aspect of any heater. CEI’s helical coil heater approaches the theoretical limits of thermal efficiency possible in a fired 2-pass heater. Even without the stack heat exchanger, its efficiency is 85 percent.


Gallons / hour

Gallons / Month

Gallons / Life

























These usages are based on a 1-million Btu/hr heat load, operating 24 hrs/day, 7 days/week, 40 weeks/yr, a 20 year heater life and No. 2 fuel oil with a heating value of 132,000 Btu/gallon (LHV)


  • CEI Helical Coil Hot Oil Heater
    HCS-series heater with optional stack heat exchanger.
  • CEI Helical Coil Hot Oil Heater
    HCS-series heater with optional stack heat exchanger.
  • Hot oil heater mounted on portable asphalt tank
    Helical coil heaters can be optionally installed on portable asphalt tanks.

Available Options:

  • Low-NOx burners (30ppm).
  • Ultra low-NOx burners (less than 9ppm).
  • Stack heat exchangers for boosting fuel efficiency.
  • Optional burner management system utilizes an exhaust stack O2 sensor to maintain heater operation in adverse climates. Reduces fuel consumption and tunes burner automatically.
  • Sock filters for longer fluid and pump life.
  • 7-day time clock.
  • Non-standard voltage (525/60, 380/50)
  • ASME code stamp.
  • CSA approved panel.
  • CRN stamped coils.
  • Class I Div. I or Class I Div. II explosion-proof components.
  • High-temperature (550°F) operation.


The heaters are very easy to maintain. Components are easy to reach. Replacement parts are readily available from CEI’s large parts inventory. We back our products with worldwide parts & service support.


For additional information on hot oil heaters, please contact Heatec, Inc — an Astec Industries company