14 McQuay IM 937
Electrical Data
Electrical Data
Field Wiring
General
Wiring must comply with all applicable codes and ordinances.
McQuay’s product warranty does not cover equipment failures
caused or contributed to by wiring not in accordance with
specifications. An open fuse or tripped MMP indicates a short,
ground or overload. Before replacing a fuse or restarting a
compressor or fan motor, locate the trouble and correct. Use
copper wire for all power lead terminations.
A single power terminal block is provided as standard, and
wiring within the unit is done in accordance with UL 508.
Each branch circuit within the control panel is individually
protected. A single field-supplied disconnect is required or a
unit-mounted, nonfused disconnect can be ordered with the
unit.
A 7/8" knockout is located on the right-hand unit upright for
locating unit power entry. 24 V 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
refrigerant equipment including motor-compressors, and
controllers, from the circuit feeder.” Select and locate the
disconnect switch within the NEC guidelines. Location
requirements per NEC are that the disconnect is located in a
readily accessible position within sight (50 feet) of the unit. A
factory-mounted, nonfused disconnect is available.
Return Air and Outside Air Sensors
All units are provided with a return air sensor. It is connected
to the input control board and is coiled and placed behind the
access panel, to the right of the control panel of the unit for
shipment. Field install it in the return air stream for proper unit
operation. The return air sensor is connected to the unit’s input
board at location AI-2.
The outside air sensor is optional and can be ordered with the
unit. It ships loose in a package and is located on the floor of
the fan section. The outside air sensor is field wired to terminal
strip TB2. It is connected at terminals 122 and 123.
The mixed air temperature sensor is already installed at the
inlet of the unit.
Mount the sensors in areas that are exposed to representative
temperature conditions. Mount them at a position that has
good air mixing and does not have stratification. Sensors can
be mounted in the ductwork using a grommet (see Figure 21).
Figure 21: Return/Outside Air Sensor Mounting
Grommet
Sensor
Ductwork
Air flow
Table 7: Compressor Motors
Compressor hp Refrigerant
208/60/3 230/60/3 460/60/3 575/60/3
RLA LRA RLA LRA RLA LRA RLA LRA
6 R-22 14.9 156 14.9 156 7.4 75 6.0 54
R-407 14.7 156 14.7 156 7.3 75 5.8 54
7 R-22 17.6 164 17.6 164 9.6 100 7.7 78
R-407————————
8 R-22 22.1 189 22.1 189 11.0 99 8.8 74
R-407————————
9 R-22 24.8 232 24.8 232 12.4 125 9.9 100
R-407————————
10 R-22 28.4 278 28.4 278 14.2 127 11.4 100
R-407 27.5 278 27.5 278 13.8 127 11.0 100
13 R-22 32.1 350 32.1 350 16.0 158 13.1 125
R-407 32.5 350 32.5 350 16.2 158 13.0 125
15 R-22 40.1 425 40.1 425 20.0 187 16.0 148
R-407 39.6 425 39.6 425 19.8 187 15.8 148
20 R-22 65.4 360 65.4 360 32.7 180 26.2 144
R-407 65.4 425 65.4 425 32.7 187 — —
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