U.L. Recognized – E56973
C.S.A. Certified – 016386-0-000

• The Backer Hotwatt Square and Rectangular Cartridge Heater is designed to distribute maximum heat within a desired area. Because they are completely enclosed, square units will furnish more usable heat for a given wattage than a comparable strip heater attached to the exterior of a mold, platen, or other equipment.
• The units are inserted in a milled slot, permitting greater lengths than would be feasible with a drilled or reamed hole. Close dimensional tolerances are held to permit intimate fit for best heat transfer to surrounding medium.
• Heating elements arranged just beneath outside surface for maximum heat transfer, minimum wire temperature, and faster heating.
• Maximum surface temperatures up to 1200°F. Designations are etched on the sheath to preserve accurate shape.
• Long, trouble free service.
• Made in U.S.A.

1. Sealed end.
2. Mica.
3. Series 300 stainless steel sheath for non-oxidizing, stable service in cavities machined for them.
4. Element wire situated in close proximity to outside surface for maximum heat transfer, minimum wire temperature, and faster heating.
5. Magnesium oxide packing.
6. Ceramic element support.
7. Teflon insulated leads: 1/4″ square. Fiberglass insulated leads: 3/8″ to 1/2″ square, 1/4″ x 5/8″ and 1/4″ x 1″ rectangular.

Lengths between or longer than those listed may be ordered.

Minimum Wattage

The following table should be used to determine the allowable voltage for low wattage miniature elements:

NA – Not Available

Standard voltage is either 120V or 240V. Other voltages are available.

All units within published amperage limits, are manufactured with 6″ (type SF1) leads; longer length leads are available. Standard insulation on 1/4″ square units is Teflon (200°C). Fiberglass (250°C) is standard on all other sizes.

Lengths between or longer than those listed may be ordered.

Lengths between or longer than those listed may be ordered.

Wattage tolerances are held to +5%, -105 at rated voltage. Width and height are always .001″ less but not more than .010″ less than the nominal (fractional) heater size; length tolerances are ±2% with a ±1/16″ minimum. This sizing is maintained so that all units are a slide fit into a standard milled slot of the size required. Thermal action will expand the unit to a snug fit for best heat conduction. To avoid early burn out, review our article on extending heater life.

After determining the wattage required and the line voltage available, determine the physical space available for heaters and the numbers of heaters required. Review Special Features.

Specify: catalog number, wattage, voltage, lead length, and special features required.
Example: SR16-7.5/750W/240V/SF1-48.