Johnson Controls York VERSECON YSWD 012, Installation Operation & Maintenance

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JOHNSON CONTROLS
FORM 145.05-NOM1 (708)
ELECTRICAL DATA
Field Power Wiring
Wiring must comply with all applicable codes and
ordinances.
A single point power terminal block is provided as
standard and wiring within the unit is done in accordance
with the National Electrical Code. All branch circuits
within the control panel are individually fused. A single
field supplied disconnect is required, or a unit mounted
non-fused disconnect can be ordered with the unit.
A ¼” hole is located on the side of the unit in the upper
portion of the electrical panel for unit power entry. A
hole saw, step drill or Greenlee punch set should be used
to increase the hole size based on the wire size required
for the calculated unit ampacity.
Disconnect
Disconnecting means are addressed by Article 440 of
the National Electrical Code (NEC), which requires
“disconnecting means capable of disconnecting air
conditioning and refrigerant equipment including
motor-compressors, and controllers, from the circuit
feeder.” The disconnect switch should be selected and
located with the NEC guidelines. Location requirements
per NEC are that the disconnect be located in a readily
accessible position within sight (50 feet) of the unit.
Electrical Service Sizing
In order to determine the electrical service required
for the Versecon unit, use the appropriate calculations
listed below from the National Electrical Code. Based
on the configuration of the unit, the calculations will
yield different MCA (Minimum Circuit Ampacity), and
MOP (Maximum Overcurrent Protection).
The MCA value is used to size the wire for the power
service to the unit. The MOP is used to size either the
breaker or fuse for the entire unit.
Using the following formulas and Tables 8 and 9,
determine the correct electrical sizing for the unit. All
concurrent load conditions must be considered in the
calculations, and you must use the highest value for any
combination of loads.
MCA
For units with cooling capability (all concurrent loads)
with or without hot water or steam heat:
MCA = 1.25 (largest motor RLA or FLA) + other
loads + 2 amps.
For units with cooling capability and non-concurrent
electric heat the following calculations are required.
In the cooling mode, the loads are composed of the
compressors and supply fan motor loads. In the heating
mode, the loads are composed of the supply fan motor
and the electric heaters. The MCA is calculated for the
unit in the cooling mode and in heating operation. The
highest value obtained is used for the MCA.
For unit in the cooling mode:
MCA = 1.25 (largest motor RLA or FLA) + other
loads + 2 amps.
For units in the heating mode:
With Electric Heater KW 50 KW or less:
MCA = 1.25 (electric heat FLA + supply fan
motor amps) + 2 amps.
With Electric Heater KW greater than 50KW:
MCA = 1.25 (supply fan motor amps) + elec-
tric heat FLA + 2 amps.
MOP
For units with cooling capability (all concurrent loads)
with or without hot water or steam heat:
MOP = 2.25 (largest motor RLA or FLA) + other
loads + 2 amps.
For units with cooling capability and non-concurrent
electric heat the following calculations are required.
In the cooling mode, the loads are composed of the
compressors and supply fan motor loads. In the heating
mode, the loads are composed of the supply fan motor
and the electric heaters. The MOP is calculated for the
unit in the cooling mode and in heating operation. The
highest value obtained is used for the MOP.