20
SINGLE POINT BOXES AND SUPPLEMENTARY FUSES
When the unit MOCP device value exceeds 60-A, unit-
mounted supplementary fuses are required for each heater cir
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cuit. These fuses are included in accessory single point boxes,
with power distribution and fuse blocks. The single point box
will be installed directly under the unit control box, just to the
left of the partition separating the indoor section (with electric
heaters) from the outdoor section. The single point box has a
hinged access cover. See Fig. 40. The single point box also in
-
cludes a set of power taps and pigtails to complete the wiring
between the single point box and the unit’s main control box
terminals. Refer to the Small Roof Top Units Accessory Elec
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tric Heater and single point box installation instructions for de
-
tails on tap connections.
All fuses on 547K units are 60-A. (Note that all heaters are
qualified for use with a 60-A fuse, regardless of actual heater
ampacity, so only 60-A fuses are necessary.)
SINGLE POINT BOXES WITHOUT FUSES
Unit heater applications not requiring supplemental fuses re
-
quire a special single point box without any fuses. The
accessory single point boxes contain a set of power taps and
pigtails to complete the wiring between the single point box
and the unit’s main control box terminals. Refer to accessory
heater and single point box installation instructions for details
on tap connections.
LOW-VOLTAGE CONTROL CONNECTIONS
Pull the low-voltage control leads from the heater module —
WHT, VIO and BRN to the 4-pole terminal board TB4 located
on the heater bulkhead to the left of the Heater module.
Connect the WHT lead from Heater circuit no. 1 to terminal
TB4-1. For 2 stage heating, connect the VIO lead from Heater
circuit no. 2 to terminal TB4-2. Connect the BRN lead(s) to
terminal TB4-3. See Fig. 39.
Fig. 39 — Accessory Electric Heater Control Connections
CONTROL AND POWER WIRING DIAGRAMS
Figures 41-43 are typical control and power wiring diagrams.
Fig. 40 — Typical Single Point Installation
Summary of Contents for Legacy 547K 14
Page 4: ...4 Fig 2 547K 14 Unit Dimensional Drawing...
Page 5: ...5 Fig 2 547K 14 Unit Dimensional Drawing cont...
Page 8: ...8 Fig 5 547K 14 Roof Curb Details...
Page 21: ...21 Fig 41 Typical Control Wiring Diagram Electromechanical with W7220 Controller...
Page 22: ...22 Fig 42 Typical Power Wiring Diagram 208 230 460 3 60 Unit Shown...
Page 23: ...23 Fig 43 Typical Power Wiring Diagram 575 3 60 Unit Shown...
Page 41: ......
