Heater Catalog - Watlow

Immersion HeatersWATROD and FIREBAR Screw PlugImmersion HeatersScrew Plug with Control AssemblyConstructed from a WATROD screw plug heater,a moisture resistant terminal enclosure and built-intemperature sensor and power controller, this assemblycomes pre-wired and ready for hook-up to any120VAC control circuit.Optional sheath materials, NPT screw plug sizes andmaterials, wattages, voltages and terminal enclosuresextend application versatility.Performance Capabilities• Watt densities up to 60 W/in 2 (9.3 W/cm 2 )• Wattages up to 20 kilowatts• Voltages up to 600VAC• Alloy 800/840 sheath temperatures up to1600°F (870°C)Features and BenefitsThree 0.475 in. (12 mm) diameter WATROD elementsbrazed to a 2 in. (51 mm) NPT brass screw plug• Produces a pressure-tight sealWATROD hairpins are repressed (recompacted)after bending• Maintains MgO density, dielectric strength, heattransfer and lifeTwo built-in thermostats, one on-off withmanual reset• Helps ensure safe operation by automatically cyclingon and off when process or sheath temperatures reacha predetermined set point selectable from 30° to 250°F(0° to 120°C)Internal mechanical contactor• Works on a 120VAC control circuit to switch highervolts/amps to the heating elementsHinged, moisture resistant terminal enclosurehas two conduit openings• Accommodates 3 /4 in. (19 mm) NPT conduit fittingsTerminal enclosures can be rotated to mate withexisting conduits• Minimal fastener adjustment requiredThermowells allow replacing the thermostat sensingelement without draining the fluid being heated• Labor required to maintain and repair is minimizedWATROD Heating ElementOn-offManualResetThermostat2 in. (51 mm) NPT Pipe ThreadInternalThermostatMechanical ContactorTypical Applications• Water heating• Commercial dishwashers and glass washers• Sterilizing equipmentApplication HintsSame as Screw Plug Immersion Heaters. See page 169for details.AccessoriesClamping Nut, Gasket and Washers–for mounting tothin-wall tanks, use optional clamping nut, gasket andwashers. To order, specify NGW.WATLOW ®235