Field Wiring; General; Unit Disconnect; Return Air And Outside Air Sensor - McQuay SWT C Series Installation And Maintenance Manual

Field Wiring

General

Wiring must comply with all applicable codes and ordi-
nances. The warranty does not cover equipment failures
caused by or contributed to wiring not in accordance with
specifications. An open fuse indicates a short, ground or
overload. Before replacing a fuse or restarting a compressor
or fan motor, the trouble must be found and corrected. Use
copper wire for all power lead terminations. Contact factory
for information concerning aluminum wire power lead ter-
minations.
A single power terminal block is provided as standard and
wiring within the unit is done in accordance with the
National Electric Code. All branch circuits within the control
panel are individually fused. A single field supplied discon-
nect is required or a unit mounted nonfused disconnect can
be ordered with the unit.
Table 7. Compressor Motors
A 7/8" knockout is located on the right-hand unit upright for
locating unit power entry. 24V field connections are suitable
for Class II wiring.

Unit Disconnect

Disconnecting means are addressed by Article 440 of the
National Electric Code (NEC) which requires disconnecting
means capable of disconnecting air conditioning and refrig-
erant equipment including motor-compressors, and control-
lers, from the circuit feeder." The disconnect switch should
be selected and located within 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.
A factory mounted nonfused disconnect is available.
Table 7. Compressor Motors
208/60/3
Compressor
HP
RLA LRA
6 17.9 156.0
10 31.2 239.0
13 35.6 350.0
Table 8. Electric Heaters
208V/60HZ/3PH
SWP UNIT SIZE
kW MBH
018 - 040 27.8 94
IM709
230/60/3
RLA LRA
16.2 156.0 8.1
28.2 239.0 14.1
32.0 350.0 16.0
230V/60HZ/3PH
FLA kW MBH FLA
77.2 34 116 85.6
Return Air and Outside Air Sensors
All units are provided with a return air sensor. The outside
air sensor is optional and can be ordered with the unit. The
return air sensor is connected to the input control board and
is coiled up and placed in the control box of the unit for ship-
ment. The return air sensor must be field installed in the
return air stream for proper unit operation. The outside air
sensor is shipped loose in a package and is located on the
floor of the fan section. The mixed air temperature sensor is
already installed at the inlet of the unit.
The sensors must be mounted in areas that are exposed to
representative temperature conditions. The sensor should be
mounted at a position that has good air mixing and does not
have stratification. The sensor can be mounted in the duct-
work using a grommet, see Figure 17.
Figure 17. Return/Outside Air Sensor Mounting
Ductwork
The return air sensor is connected to the unit's input board at
location AI4, see IM710. The outside air sensor is field
wired to terminal strip TB2. The sensor is to be connected at
terminals 124 and 125.
400/50/3 460/60/3
RLA LRA RLA
70.0 8.1
125.0 14.1
158.0 16.0
400V/50HZ/3PH 460V/60HZ/3PH
kW MBH FLA kW
25.7 88 37.2 34
Sensor
Grommet
575/60/3
LRA RLA
70.0 6.5 54.0
125.0 11.3 80.0
158.0 12.8 125.0
575V/60HZ/3PH
MBH FLA kW MBH
116 42.8 34 116
LRA
FLA
34.2
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