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Screw Plug Immersion Heaters

Screw Plug Immersion Heaters consist of tubular elements welded or brazed into a threaded screw plug which can then be inserted into a threaded opening in a tank wall or through a mating full or half coupling.

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Watt Densities for Typical Applications

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8 watts/in2 (1.3 watts/cm2)

Typical Applications: Fuel Oils (Bunker C and Number 6)

Recommended Materials

Screw Plug: Steel

Elements: Steel

Housing: NEMA 1

3-Phase only

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15 watts/in2 (2.3 watts/cm2)

Typical Applications: Medium Weight Oils ● Heat Transfer Oils

Recommended Materials

Screw Plug: Steel

Elements: Steel

Housing: NEMA 1

3-Phase and 3-Phase convertible to 1-Phase

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16 watts/in2 (2.5 watts/cm2)

Typical Applications: Medium Weight Oils ● Heat Transfer Oils ● Liquid Paraffin

Recommended Materials

Screw Plug: 304 Stainless Steel

Elements: Incoloy® 800

Housing: NEMA 1

3-Phase only

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23 watts/in2 (3.6 watts/cm2) (B)

Typical Applications: Forced Air & Gases ● Caustic Solutions ● Degreasing Solutions

Recommended Materials

Screw Plug: 304 Stainless Steel

Elements: Incoloy® 800

Housing: NEMA 1

Dual-Voltage heaters are 1-Phase and are wired for the higher voltage unless otherwise specified. 3-Phase and 3-Phase convertible to 1-Phase

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23 watts/in2 (3.6 watts/cm2) (A)

Typical Applications: Lightweight Oils ● Degreasing Solutions ● Heat Transfer Oils

Recommended Materials

Screw Plug: Steel

Elements: Steel

Housing: NEMA 1

Dual-Voltage heaters are 1-Phase and are wired for the higher voltage unless otherwise specified. 3-Phase and 3-Phase convertible to 1-Phase

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48 watts/in2 (7.5 watts/cm2)

Typical Applications: Process Water

Recommended Materials

Screw Plug: 304 Stainless Steel

Elements: Incoloy® 800

Housing: NEMA 1

Dual-Voltage heaters are 1-Phase and are wired for the higher voltage unless otherwise specified. 3-Phase and 3-Phase convertible to 1-Phase

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60 watts/in2 (9.3 watts/cm2) (A)

Typical Applications: Clean Water

Recommended Materials

Screw Plug: Brass

Elements: Copper

Housing: NEMA 1

Dual-Voltage heaters are 1-Phase and are wired for the higher voltage unless otherwise specified. 3-Phase and 3-Phase convertible to 1-Phase

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60 watts/in2 (9.3 watts/cm2) (B)

Typical Applications: Deionized Water ● Demineralized Water

Recommended Materials

Screw Plug: 316 Stainless Steel

Elements: 316 Stainless Steel

Housing: NEMA 1

3-Phase and 3-Phase convertible to 1-Phase

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Construction Styles

General Purpose Hot Water Tank Heater

1″-111⁄2 NPSM Brass Plug with O-Ring gasket (NPT optional) Incoloy® 800 Tubular Element 10-32 plated screw terminals 90°C epoxy seal standard Optional ceramic terminal block for high temperature applications

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Self-Contained Screw Plug Heater

This immersion heater is specifically designed for commercial dishwashers and sterilizing equipment. However, due to the unique construction characteristics of these heaters, they are readily adaptable for use in other water heating applications. The heating elements are prewired to a Definite Purpose contactor, thermostat and high limit cutout. The thermowell is located at the top of the element bundle for fast shut-off response, preventing overheating due to low water level conditions.

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Standard Screw Plug Heater

Four Standard Screw Plug Sizes—1″, 1-1/4″, 2″, 2-1/2″ Recompacted element bends restore insulation resistance after forming Corrosion-Resistant electrical wiring hardware Silicone resin element seal standard Special sheath materials available Special straight bulkhead or European thread fittings available

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Sheath Materials

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Incoloy 800

Nickel 30-35%, Chromium 19-23%, Iron balance. The high nickel content of this alloy contributes to its resistance to scaling and corrosion. Used in air heating and immersion heating of potable water and other liquids.

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316/316L Stainless Steel

Chromium 16-18%, Nickel 11-14%, Iron balance. (316L – Low Carbon) Modified with the addition of Molybdenum (2-3%) to improve corrosion resistance in certain environments, especially those which would tend to cause pitting due to the presence of chlorides. Applications include deionized water. Maximum Sheath Temperature: 1200°F / 649°C

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304/304L Stainless Steel

Chromium 18-20%, Nickel 8-11%, Iron balance. (304L – Low Carbon) Used in the food industry, medical, and chemical heating. Maximum Sheath Temperature: 1200°F (649°C)

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Copper

Standard Copper Alloy A low temperature, inexpensive material used mainly for clean water heating. Maximum Sheath Temperature: 350°F / 177°C

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Steel

Low Carbon Used for high to low viscosity oils, asphalt, tar, wax, molten salt, heat transfer liquid media and other compatible solutions.

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Screw Plug Materials

Brass Screw Plug

Used for clean water and other non-corrosive materials

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304 SS Screw Plug

Used for corrosive materials

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316 SS Screw Plug

Used for corrosive materials

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Steel Screw Plug

Used for oils and other non-corrosive materials

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Request Other Screw Plug Materials

If your filter selections do not return your desired results from our standard configurations, please continue to select your Specifications. When you are finished, save your selections in the Wish List (using the button at the right of this page) and follow the steps to submit them to Tempco.

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Surface Treatments

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Electro-Polishing

Electro-Polishing is an electrochemical process that removes surface imperfections and contaminants, enhancing the corrosion resisting ability of the stainless steels. The resultant surface is clean, smooth and bright. Many medical and food applications require this finish.

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Passivation

Passivation removes surface contamination, usually iron, so that the optimum corrosion resistance of the stainless steel is maintained. Surface contamination would come from the small amount of steel that may be worn off a tool during the manufacturing process. Passivating is accomplished by dipping the heater in a warm solution of nitric acid.

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Electrical Terminations

Type 1N Terminal Box

For Use with Thermostat: N/A

For Screw Plug Heater Sizes: 1″ 1-1/4″ 2″ 2-1/2″

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Type 1T Terminal Box

For Use with Thermostat: Single Pole

For Screw Plug Heater Sizes: 1″ 1-1/4″ 2″ 2-1/2″

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Type 6T Terminal Box

For Use with Thermostat: Double Pole

For Screw Plug Heater Sizes: 1″ 1-1/4″ 2″ 2-1/2″

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Type 2N Terminal Box

For Use with Thermostat: N/A

For Screw Plug Heater Sizes: 1″ 1-1/4″ 2″ 2-1/2″

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Type 2T Terminal Box

For Use with Thermostat: Single Pole

For Screw Plug Heater Sizes: 1″ 1-1/4″

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Type 3T Terminal Box

For Use with Thermostat: Double Pole

For Screw Plug Heater Sizes: 2″ 2-1/2″

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Type 3N Terminal Box

Alternate Nema 1 Housing

For Use with Thermostat: N/A

For Screw Plug Heater Sizes: 1″ 1-1/4″ 2″ 2-1/2″

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Type 4N Terminal Box

For Use with Thermostat: N/A

For Screw Plug Heater Sizes: 1″ 1-1/4″ 2″ 2-1/2″

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Type 4T Terminal Box

For Use with Thermostat: Single Pole

For Screw Plug Heater Sizes: 1″ 1-1/4″

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Type 5T Terminal Box

For Use with Thermostat: Single or Double Pole

For Screw Plug Heater Sizes: 2″ 2-1/2″

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Screw Terminals No Housing

No Terminal Box

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Request Other Electrical Termination

If your filter selections do not return your desired results from our standard configurations, please continue to Refine Results for your specifications. When you are finished, save your selections with the Save Results for Quote button (at the right of this page) and choose Request for Quote for further assistance.

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Thermostats

DPST Thermostat

Double Pole – Single Throw Thermostats: Style B, Style C

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SPST Thermostat

Single Pole – Single Throw Thermostats: Style A, Style D, Style F

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Request Other Thermostat

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Thermostat Options

Stuffing Box Assembly

The Stuffing Box Assembly is used to seal the thermostat capillary when the sensing bulb (3/8″ max. OD) is immersed directly in a liquid rather than in a thermowell. The Stuffing Box consists of six slotted washers used to compress a graphite packing into a 3/8″ NPT male pipe thread fitting. Assembly Instructions Feed sensing bulb through hole in upper and lower fitting. Insert washers and packing into top cavity of lower fitting. Upper fitting then screws into lower fitting, creating the seal. Part Number: TST-109-101

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Thermowells

Stainless Steel or Plain Steel: Thermowells provide protection for bulb and capillary sensors. They are supplied with a 1/2″ NPT male thread for mounting and a 3/8″ NPT internal thread that can be used with the stuffing box assembly to secure the capillary to the well. ID: 0.50″, OD: 0.56

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Resources & Part Numbers

Resources

Catalog PDF Selection Guide Wiring Diagrams Chemical Compatibility Guide NEMA Enclosure Ratings Guide Process Heater Gallery

In-Stock Parts

Screw Plug Immersion Heater Preconfigured Part Numbers Self-Contained Immersion Heater Preconfigured Part Numbers GP Hot Water Tank Heater Preconfigured Part Numbers