Carrier 39LA Installation, Start-up And Service Instructions Manual

Also see for 39L Series: Installation, Operation, and Start-Up Instructions

Contents

Carrier 39LA Installation, Start-up And Service Instructions Manual Manual pdf 28 page image

28Table 11 — Field Wiring for Incoming ConductorsSized for 125% of Heater LoadLEGEND*Values are based on Table 310-16 of the NEC (National ElectricalCode) for 75 C insulated copper wire. Not more than 3 conductorsin a raceway.NOTES:1. Be sure to consider length of wiring run and possible voltagedrops when sizing wires.2. Field power wiring — Heaters are furnished with a terminalblock sized for incoming copper conductors with 75 C insulationrated to carry at least 125% of the heater load. However, con-ductors can be sized to carry 100% of the heater load if theheater is rated at 50 kW or more, and the heater is controlled bya cycling device such as a multi-stage thermostat, step control-ler, or SCR (silicon control rectifier) power controller. Terminalblocks and knockouts are sized to handle either 100% or 125%conductors.Discharge Modification — If field modification ofdischarge position is required, 39L fans can be converted (by askilled mechanic) to any standard hand and discharge withoutany additional parts. (NOTE: This does not apply to a modelchange conversion.) All mounting holes are prepunched.To convert a 39L fan, note the following:1. Sizes 03-18 without inlet guide vanes (IGVs) — SeeFig. 33. It is not necessary to remove the bearing supportchannels from the fan housing.Sizes 21 and 25 without IGV and 06-25 with IGVs —See Fig. 34. The “A” frame support must be removed. Tochange from upblast to horizontal discharge or fromhorizontal to upblast discharge, the bearings must berelocated to keep the wheel centered in the housing. Tochange from upblast front (UBF) to upblast rear (UBR)or from top horizontal front (THF) to top horizontal rear(THR) or vice versa, turn the entire fan housing 180 de-grees about its base.2. Inlet guide vane actuators and linkages, where provided,may be moved to the opposite fan scroll side sheet.NOTE: The swivel joint must be at the 12 o’clock posi-tion on the IGV assembly. (See Fig. 12.) The jackshaftcrankarm, attached to the jackshaft at the “A” frame, willsit vertically up on all units. Figure 12 illustrates a jack-shaft crankarm in the vertical up position.3. The fan shaft may be driven out and reinstalled to placethe drive pulley on the opposite end.4. The fan scroll is prepunched for horizontal or vertical dis-charge to match the support angles at the base of the unit.5. The motor and motor base may be rotated to place themotor at the front or rear of the unit. Proper location isthat which results in the longest drive center line distance.The motor conduit box location may need to be reversed.6. When hand of fan is changed, it may be necessary to turnthe discharge panel inside-out to fit correctly with the fandischarge. In this case, remove the existing insulation andinstall new duct-liner type insulation on the opposite sideof the discharge panel.7. Rebalancing of the unit is recommended.WIRE SIZE(AWG or kcmil)LOAD AMPS* WIRE SIZE(AWG or kcmil)LOAD AMPS*Copper Copper12 16 1/0 12010 24 2/0 1408 40 3/0 1606 52 4/0 1844 68 250 2043 80 300 2282 92 350 2481 104 400 268500 304AWG — American Wire Gagekcmil — Thousand Circular MilsFig. 33 — Fan Discharge Positions, Fans without IGVsLEGENDTHF — Top Horizontal FrontTHR — Top Horizontal RearUBF — Upblast FrontUBR — Upblast Rear