No. 837 is a 1450°F electrically heated tempering furnace used for preheating prior to welding and various post-welding heat treatments. Workspace dimensions measure 60 inches wide x 60 inches deep x 60 inches high. Heat is provided by 180 KW installed in nickel chrome wire coils supported by a stainless steel framework. A rear wall-mounted, heat-resisting-alloy recirculating fan, powered by a 25-HP motor with V-belt drive and water-cooled bearings, is also on this unit. No. 837 features an air-operated vertical lift door and numerous safety and control components, including a programming and recording temperature recorder, SCR power controller, manual reset excess temperature controller with separate contactors and a recirculating blower airflow safety switch.