Electrical
To avoid possible injury or death
due to electrical shock, open the
power supply disconnect switch
and secure it in an open position
during installation.
Use only copper conductors
for field installed electrical
wiring. Unit terminals are not
designed to accept other types
of conductors.
Electrical: Line voltage
All field installed wiring, including
electrical ground, must comply
with the National Electrical
Code as well as all applicable
local codes. Refer to the unit
electrical data for fuse sizes.
Consult wiring diagram for field
connections that must be made
by the installing (or electrical)
contractor. All final electrical
connections must be made with
a length of flexible conduit to
minimize vibration and sound
transmission to the building.
General line voltage wiring
Be sure the available power is
the same voltage and phase
shown on the unit serial plate.
Line and low voltage wiring must
be completed in accordance
with local codes or the National
Electric Code, whichever is
applicable.
Three phase wiring is similar
except that all four power wires
are directly connected to the
contactor.
Power connection:
Line
voltage connection is made by
connecting the incoming line
voltage wires to the “L” side of
the contactor as shown in
Figure 13 or to the optional
service disconnect when
provided. Consult electrical data
tables for correct fuse size.
Transformer
All 208-230 volt units are factory
wired for 208 volts. If supply
voltage is 230 volts, installer
must rewire transformer. See
wiring diagram for connections.
Special note for AHRI testing
To achieve rated airflow for
AHRI testing purposes on all
PSC products, it is necessary
to change the fan speed to
“HI” speed and clean the coil
with a mild surfactant such as
Calgon to remove the oils left
by manufacturing processes
and enable the condensate to
properly “sheet” off of the coil.
Electrical: Power wiring
Electrical: Low
voltage wiring
Figure 12: Single phase electrical control box
Table 8: Transformer loading
Component
VA
Typical blower relay
6 - 7
Typical reversing valve solenoid
4 - 6
30A compressor contactor
6 - 9
Subtotal
16 - 22
+ PCB controller (5 - 9 VA)*
21 - 31
Remaining VA for accessories
19 - 29
*Standard transformer is 50VA. Optional 75VA
transformers are available.
Note:
n
n
All 460V units require neutral regardless
of motor.
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