Hevi-Duty HDT-5610 Electric Box Furnace 2300°F 5KW 90V AS-IS Bad Thermocouple

Hevi-Duty HDT-5610 Electric Box Furnace 2300°F 5KW 90V AS-IS Bad Thermocouple

The Hevi-Duty HDT-5610 is a vertical-lift-door electric box furnace rated to 2300°F (1260°C) maximum. It is built by Hevi Duty Electric Co. of Milwaukee, Wisconsin, and features a refractory firebrick chamber with counterweight-assisted door lift and a Barber-Colman Model 293 temperature controller. This unit is being sold AS-IS: the thermocouple is defective and the furnace will not activate the heat chamber under normal operation. When the thermocouple is bypassed, the heating elements do power on, but closed-loop temperature control is not functional.

Specifications & What's Included

• Model: Hevi-Duty HDT-5610
• Max Temperature: 2300°F (1260°C)
• Safe Working Temperature: 2300°F
• Furnace Operating Voltage: 90V AC
• Power Rating: 5 KW
• Controller Input Voltage: 208V AC, 2-wire, single phase
• Chamber Interior Dimensions: 18" Deep × 6" High × 7" Wide
• Temperature Controller: Barber-Colman Model 293 — analog meter display, 0–700°C / 0–2500°F scale
• Panel Meters: General Electric AC Voltmeter (0–150V) and AC Ammeter (0–100A)
• Power Input Control: ALC Percent Input dial (variable input control)
• Timer: Integrated cycle timer with bypass switch
• Door Mechanism: Counterweight chain-lift vertical door
• Mounted on: Black steel cabinet base with casters
• Included accessories: Furnace tongs, crucible tongs, and power conduit/cable assembly
• Known fault: Thermocouple is defective — furnace does not activate heat chamber in normal operation. Heating elements function with thermocouple bypassed; temperature control is not operational in bypass mode.

Operational Notes (documented by our staff)

• Bypass switch DOWN: power applied to heater until set point is reached, then heater shuts off and temperature control stops; press Reset to restart the heat controller
• Bypass switch UP: temperature is controlled to the set point
• Timer switch (left of timer) UP: timer is bypassed and heater runs continuously
• Power-on delay: heater begins approximately 1–3 minutes after power is applied

Applications

Hevi-Duty electric box furnaces like the HDT-5610 are workhorses of industrial and laboratory heat-treating applications. They are used for annealing, hardening, tempering, brazing, and sintering of metals and ceramics, as well as ashing and calcination in analytical and research labs. The vertical lift-door design is well suited to loading crucibles, small castings, and test specimens. The 2300°F rating covers the full range of common carbon and alloy steel heat-treating temperatures as well as many ceramic firing applications. Hevi Duty Electric Co. was a long-established Milwaukee manufacturer of industrial resistance-heating equipment; their box furnaces from this era — identifiable by the counterweight door mechanism and Barber-Colman controllers — were widely used in university labs, production shops, and foundries from the mid-20th century onward. A unit like this with a known, replaceable fault (thermocouple) is a practical acquisition for a shop or lab with the ability to source and install a compatible thermocouple and restore full closed-loop temperature control.