42
start a system because the refrigerant will
migrate to the cold part of the system
(condenser) and make it difficult for
refrigerant to flow.
The low ambient system maintains normal
head pressure during periods of low ambient
temperatures by controlling condenser air
flow by modulating fan speed. By reducing
condenser air flow, the condenser heat
rejection capacity is reduced. This allows
unit operation down to 0
°
F.
During higher ambient temperatures, the
entire condenser is required to condense
refrigerant. During these higher ambient
temperatures, full condenser air flow is
required to maintain system capacity. The
VFD controlled condenser fan low ambient
head pressure control will modulate the
condenser air flow to maintain proper head
pressure. Along with electronic expansion
valves, VFD controlled condenser fans
optimize system performance.
Electrical
The electrical power connections are made in
the electrical control compartment.
The microprocessor control furnished with
the unit is supplied with its own power supply
factory wired to the main power of the
outdoor mechanical room.
Verify the unit nameplate voltage agrees with
the power supply. Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit.
Size supply conductors based on the unit
MCA rating. Supply conductors must be
rated a minimum of 167°F (75°C).
Route power and control wiring, separately,
through the utility entry. Do not run power
and signal wires in the same conduit. Power
and signal wires in the same conduit can
cause electrical interference.
Table 4 - Nameplate Voltage Markings
Voltage Feature
Nameplate
Voltage
Marking
Min/Max
VAC
2 230V/3Φ/60Hz
230
197/252
3 460V/3Φ/60Hz
460
456/504
4 575V/3Φ/60Hz
575
570/630
8 208V/3Φ/60Hz
208
197/228
Protect the branch circuit in accordance with
code requirements. The unit must be
electrically grounded in accordance with
local codes, or in the absence of local codes,
the
current
National
Electric
Code,
ANSI/NFPA 70 or the current Canadian
Electrical Code CSA C22.1.
Power wiring is to the unit terminal block or
main disconnect. All wiring beyond this point
has been done by the manufacturer and
cannot be modified without affecting the
unit's agency/safety certification.
Electric
shock
hazard.
Before
attempting to perform any installation,
service, or maintenance, shut off all
electrical power to the unit at the
disconnect switches. Unit may have
multiple power supplies. Failure to
disconnect power could result in
dangerous operation, serious injury,
death or property damage.
WARNING
Summary of Contents for LZ Series
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