PHOTOGRAPH 908
MODIFIED MODEL HD-484848-GF HEAVY DUTY FURNACE, Serial No. 700045
for heat treating

-maximum operating temperature: 2000°F
-workspace dimensions: 48" wide x 48" deep x 48" high
-1,000,000 BTU/HR installed in four (4) modulating natural gas burners with floor mounted combustion air blower
-7" thick insulated walls comprised of 5" of 2300°F firebrick, 2" of 1700°F ceramic fiber; 7" thick floor insulation comptised of 4-1/2" of 2300°F firebrick and 2-1/2" of 1900°F block insulation
-firebrick plate hearth supported by firebrick piers
-air operated vertical lift door
-automatic door switch to drive burners to low fire when door is opened
-safety equipment required by IRI, FM and National Fire Protection Association Standard 86 for gas-heated equipment
-digital indicating temperature controller
-manual reset excess temperature controller with separate contactors