Circulation & In-Line Heaters

Indeeco circulation heaters are used to maintain, raise, preheat and boost process temperatures from -50° F to 1200° F for a wide variety of liquids and gases found in commercial, industrial and military applications.

Indeeco’s circulation and in-line heaters are specifically designed for each unique process application, maximizing performance and reliability.


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Indeeco has been manufacturing circulation heaters since 1929. Aside from our long history there are two main advantages to using an Indeeco circulation heater.

Customized for your application
Each application is unique in that process parameters differ. By selecting a custom heater you guarantee that the heater will operate and perform at a level that delivers your desired process requirement.

Consultative approach to design
When you chose to work with Indeeco, you’ll be working directly with an electric heating expert. We’ll work to understand your unique application and understand your desired process outcome.

Performance Features

Wattages up to 8.5 megawatts

Watt densities up to 100 w/in2

Voltages up to 600V

Process temperatures up to 1,200ºF

Flange sizes up to 36″ and Class 2500 ASME B16.5

ASME certification & PED/PE(S)R compliance available

Standard construction includes a screw plug or pipe flanged immersion heater

Six heater mounting options available

Multiple shell and heater materials available

Multiple enclosure options available

Standard Features

ANSI B16.5 Class 150 or Class 300 flange 2” up to 36″

Designed to fit into schedule 40 or schedule STD pipe for the given flange size

Flange material A105 carbon stl, A182 304/304L or 316/316L stainless steel

Element sheath materials available: steel, 304 SST, 316 SST, 321 SST, incoloy 800, incoloy 840, copper

Epoxy or RTV sealed heating elements to prevent moisture absorption

Stainless steel welded bussing to eliminate loose connections

Heater circuits divided into 48A max as default

Heavy duty, low pressure drop design, 304 SST element support spacers provided on 24” centers

Spacer support rods provided on 10” and larger flange sizes

General purpose, weatherproof, or hazardous location terminal enclosure

Lifting lugs for heaters 4” and larger

Nitrile bonded fiber, or SST/graphite spiral flange gasket provided as a standard


  • Class I, Division 2*, Groups A, B, C and D
  • Class I, Division 1, Groups B, C and D
  • Class II, Division 1, Groups E, F and G
  • UL STD 50, Type 4 or 4X
  • II 2 G D*
  • Ex db IIB+H2 Tx or Txxx°C Gb*
  • Ex tb IIIC Txxx°C TL xxx°C Db* IP66

*pipe flange only

Optional Features

Extended terminal box
Provided when heater operating above 500° F to allow for cooler operation of the terminal box. This allows the heating elements to be sealed with epoxy or RTV and for the customer to provide incoming wire with a much lower insulation temperature rating.

The heater can be supplied in accordance with ASME section VIII Div. 1 U-Part stamped and certified.

Pressure Equipment Legislation
For markets within the European Union Indeeco offers compliance to the Pressure Equipment Directive (2014/68/EU) and for the UK compliance to the Pressure Equipment (Safety) Regulations 2016 (S.I. 2016:1105)

Bulb and capillary pilot duty or load carrying thermostats can be provided to control the heater or to provide over-temperature protection. The thermostat bulb can be installed in a thermowell to sense process or element sheath temperature.

Type J or K thermocouples can be provided to monitor the process or element sheath temperatures. Thermocouples provided with a ceramic wafer head and screw terminals for ease of wiring. Alternate type E or T available

Hermetically sealed element terminations
A ceramic to metal soldered seal can be provided to eliminate the possibility of moisture from entering the heating element.

Removable bussing
Allows troubleshooting and isolation of a failed heating element.

Construction utilizes alternating half baffles spaced closely to cause increased flow velocity across the heating elements to allow better heat transfer from the elements to the fluid.

Ventilated general purpose cover
Provides means for heat to exhaust from the terminal box to minimize heat buildup.

Add support rods for flange sizes 8” and smaller
Support rods can be added to high flow heaters to keep the element support spacers in place.

Larger heater circuits for greater than 48A per circuit

Heavy wall pipe design
Element bundles with smaller outside diameter can be provided for any flange size requested.

Ring and cover weatherproof or corrosion resistant enclosures
Heavy duty pipe and plate construction.

Other element sheath, flange, and vessel materials available

Flange ratings available up to Class 2500

Inlet and Outlet Nozzle Connections
All inlet and outlet materials are compatible with the pressure vessel material and pressure class rating.Vessel sizes from 11⁄4 to 8 inches are typically configured with Male National Pipe Thread (MNPT) nozzles. Optional NPT and flange sizes can be supplied to mate with existing piping. 10 inch and larger vessels are supplied with Class 150 inlet and outlet flanges. Optional Class 300 or Class 600 can be provided to mate with existing piping.

Support Saddles
To mate with an existing installation, customized support saddle(s) and/or mounting lugs are available. To order, specify mounting lugs or support saddles and supply a dimensional drawing. Available on all sizes, standard on 10” vessels and larger.

High-Temperature Thermal Insulation
To minimize heat loss, the pressure vessel’s standard one inch thermal insulation wrap may be replaced with thicker and/or higher temperature insulation.Vessels may also be supplied with a primer coating without insulation.

Pressure Vessels
A variety of materials, flange sizes and pressure classes. Ratings to ANSI class 2500 pressure class are available for high-pressure applications.

Protective Steel Jacket (Shroud)
To protect circulation heaters from weather or wash-down conditions, partially welded (standard) outer protective steel jackets are available. Standard steel, or made-to-order 304 or 316 stainless steel or aluminum can be supplied. Jacket diameter is dependent upon thermal insulation thickness.



Air Heating (Process)


Anodizing Equipment

Automotive and Engines

Chemical Processing


Cryogenic Processing

Degreasing Tanks

Desalinization Equipment

Dessicant Drying


Food Processing

Freeze Protection

Fuel Oils

Gasoline Refining

Heat Transfer Systems

High Pressure Air or Gases

Hydraulic Oils

Laboratory Work

Lubrication Oils

Metal Cleaning Baths


Oil Purifiers

Oil Refining


Paint Lines


Pipeline Heating

Plastic Machinery and Processes


Plating Tanks



Process Air and Liquids

Purification Systems


Rolls and Cylinders

Steam Heating


Tank Heating (Process, Storage)


Wash Tanks

Waste Water/Sewage Treatment

Water (Deionized, Potable, Process)


Closed Tank Heating

Watt Density

Percentage of Wattage

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