Duct Heater Construction

DUCT HEATER CONSTRUCTION
ALL HEATRIX DUCT HEATERS ARE BUILT TO CONFORM TO U.L. AND N.E.C. REQUIREMENTS AND ARE LISTED FOR ZERO CLEARANCE.


HEATING ELEMENTS OPEN COIL
HEATERS SHALL BE BUILT USING TYPE "C" NICHROME WIRE (A GRADE WIRE OPTIONAL), SUPPORTED IN A CERAMIC STEATITE FLOATING BUSHING. THE CERAMICS ARE THEN SUPPORTED BY A GALVANIZED STEEL FRAME. STANDARD SPACING FOR ELEMENT CROSS SUPPORTS IS 3 INCHES ON CENTER. ELEMENT FRAME ASSEMBLIES ARE THEN MOUNTED INTO A GALVANIZED STEEL WRAP. GRADE "A" WIRE IS AVAILABLE WHEN REQUESTED.

OVERTEMPERATURE PROTECTION
ALL DUCT HEATERS ARE FURNISHED WITH AN AUTOMATIC DISC TYPE THERMAL CUTOUT FOR PRIMARY PROTECTION, WITH A MANUALLY RESETABLE DISC TYPE THERMAL CUTOUT FOR SECONDARY PROTECTION. EXCEPT "F" MODEL WHICH USES A FUSABLE LINK AS SECONDARY PROTECTION.

INTERNAL WIRING
ALL WIRING USED SHALL BE U.L. LISTED 105 C STANDARD WIRE.

OVER CURRENT PROTECTION
ALL HEATERS SHALL BE FUSED IN ACCORDANCE WITH APPLICABLE U.L. STANDARDS AND THE NATIONAL ELECTRIC CODE. CIRCUIT FUSING IS REQUIRED WHEN A DUCT HEATER CIRCUIT OR CIRCUITS EXCEED 48 AMPS. IF THE CIRCUIT DOES NOT EXCEED 48 AMPS THEN CIRCUIT FUSING IS NOT REQUIRED BY CODE BUT MAY BE ADDED AS A FACTORY INSTALLED OPTION.

CONTROLS
NUMEROUS CONTROL OPTIONS ARE AVAILABLE FOR HEATRIX DUCT HEATERS, ALL OPTIONS ARE LISTED IN THIS CATALOG. ALL COMPONENTS ARE U.L./C.S.A. LISTED.

FIELD WIRING
ALL HEATERS WILL BE FURNISHED WITH LINE TERMINALS CAPABLE OF HANDLING 125% OF THE CONNECTED LOAD. HEATERS REQUIRING LARGER THAN 500 MCM INCOMING FIELD FEED WILL BE SUBDIVIDED INTO SMALLER FEEDS TO MEET U.L. REQUIREMENTS.

CONTROL PANEL CONSTRUCTION
A MINIMUM OF 20 GAUGE GALVANIZED STEEL IS USED IN CONSTRUCTION OF ALL HEATERS, HEAVIER GAUGES ARE USED ON LARGER MODELS. HEATERS INCLUDE SPOT WELDED CONSTRUCTION, FALSE BOTTOM ON "M" MODELS, CONTINUOUS NICKEL PLATED HINGED COVER FOR CONTROL PANELS ON ALL MODELS EXCEPT "F" WHICH ARE CONSTRUCTED WITH A SCREW ON TYPE COVER. "M" MODELS THAT DO NOT INCLUDE A DOOR INTERLOCK DISCONNECT SWITCH INCORPORATE A SPRING LOADED LATCHING DEVICE IN THE COVER ASSEMBLY.