Product manual

20 McQuay IM 782-4
Installation Guidelines
Variable Frequency Drive (VFD) - Optional
1 When the unit is provided with a VFD only, refer to the
VFD manual for wire size and torque requirements. A fast-
blow fused disconnect is recommended for VFD
applications. Motor operation below 20 Hz is not
recommended. For typical wiring diagrams, see Figure 29
and Figure 30.
2 Refer to OM 844-1 (MD2 drives) or OM 895 (MD3 drives)
for VFD set-up details. The drives are installed with only
default programming and are to be field configured to meet
application requirements. Information on ATV11 drives
may be found in VFD manufacturer’s manuals.
Starters and Disconnect - Optional
1 The fan motor is factory wired to an externally mounted
control box. Control box options include: disconnect-
only (fused and non-fused) and starter-fused disconnect
transformer.
2 A fast-blow fused disconnect (J-type fuses) is used in
VFD applications.
3 A fused control transformer allows the fan to be
sequenced by standard 24-volt thermostat or controller.
4 An indoor panel with tool access hinged door houses all
the components and is generally mounted on the unit’s
bulkhead panel. The panel enclosure has several
knockouts located on the side, top, and bottom.
5 All field wiring must be in conformance with the
National Electric Code and local restrictions.
6 Refer to Figure 27 and Figure 28 for typical disconnect-
only wiring diagrams. Refer to Figure 33 and Figure 34
for typical full control box diagrams.
Figure 24: Control Box Nomenclature
Note: There are 16 total characters in the nomenclature description.
Other nomenclature examples:
CB120.3312L02-DF
CB120.3312L02DFB
CB5720.034R25SDT
CB5720.034R25--D
WARNING
Fire hazard. Failure to use fast-blow J-type fuses could
result in property damage, injury, or death. Fast-blow fuses
must be installed upstream of a VFD.
AVERTISSEMENT
Risques d’incendie. À défaut d’installer un sectionneur à
fusible à action rapide de type J, cela peut entraîner des
dommages à la propriété, des blessures ou la mort.
Un sectionneur à fusible à action rapide de type J doit être
installé avant le variateur de fréquence
CB201.0011L02CDT
Control Box
McQuay Unit Size
(1 - 4) Box Size
CDT = Contactor/Disconnect/Transformer
SDT = Starter/Disconnect/Transformer
D = Disconnect Only (Non-Fused)
DF = Disconnect Only (Fused)
DFB = Disconnect Only (Non-Fused) w/Fuse Block
(1.00) Horsepower
(208) Volts
(1) Phase
L = Left Hand
R = Right Hand