17
YORK INTERNATIONAL
FORM 150.52-NM2 (1001)
CONDENSER
Fans
Condenser fans are made of a corrosion-resistant alu-
minum hub and glass fiber, reinforced polypropylene
composite blades molded into low-noise, full airfoil
cross-section for maximum efficiency. They are stati-
cally and dynamically balanced for vibration-free op-
eration, and positioned in extended, formed steel ori-
fices for low sound and maximum efficiency.
Motors
Condenser fan motors are high-efficiency, direct-drive,
6-pole, 3-phase, Class F, current-overload protected,
totally enclosed (TEAO) type with double-sealed per-
manently lubricated ball bearings.
Condenser Coils
Fin and tube condenser coils are made of seamless, in-
ternally enhanced, high-condensing coefficient, corro-
sion resistant copper tubes arranged in staggered rows
and mechanically bonded to corrosion-resistant alumi-
num alloy fins with full height fin collars. Design work-
ing pressure is 31 bar (450 PSIG), and each coil is pres-
sure tested to 34 bar (495 PSIG) to ensure quality.
Refrigerant Circuit
There are independent refrigerant circuits per compres-
sor, each using copper refrigerant pipe formed on com-
puter controlled bending machines. This eliminates over
60% of system piping brazed joints, as compared to
designs that use fittings, resulting in a highly reliable
and leak-resistant system.
Liquid line components include: manual shutoff valve
with charging port, high-absorption removable core fil-
ter-drier, solenoid valve, sightglass with moisture indi-
cator, and reliable thermostatic expansion valves.
Suction and discharge lines are provided with manual
compressor shutoff service valves. The suction line is
equipped with closed-cell insulation.
POWER AND CONTROL PANELS
The power and control panels are divided into power
sections for each compressor and associated fans: a
control section and an electrical options section. Power
and control panels are housed in NEMA 3R/12 (IP55)
rain/dust tight, powder painted steel cabinets with hinged,
latched and gasket sealed outer doors equipped with
wind struts for safer servicing. Standard part-wind start
provides reduced inrush current during compressor
motor start, compared to across-the-line start.
Each power compartment contains: Compressor and
fan starting contactors; fan motor external overloads,
control circuit serving compressor capacity control; com-
pressor and fan contactor coils; and compressor motor
overloads.
The current transformers for the compressor motor over-
load sense each phase, as an input to the microproces-
sor. This protects the compressor motors from damage
due to: low input current, high input current, unbalanced
current, single phasing, phase reversal and compressor
locked rotor.
The control section contains: On/Off Switch,
MicroComputer keypad and display, Microprocessor
Board, I/O Expansion Board, relay boards and power
supply board.
The options section contains: A control circuit trans-
former complete with service switch providing 115/1Ø
power to the unit control system.
Electrical options are as described in “Accessories and
Options”.
MICROPROCESSOR CONTROLS
The Microprocessor panel provides the following func-
tions and displays:
• A liquid crystal 40 character display with text pro-
vided on two lines and light-emitting diode back-
lighting for outdoor viewing.
• A color-coded, 32 key, sealed keypad with sections
for Display, Entry, Setpoints, Clock, Print, Program
and Unit On/Off.
The standard controls include:
• Brine chilling thermal storage
• Automatic Pumpdown
• Run signal contacts
• Demand load limit from external building automa-
tion system input
• Remote reset liquid temperature reset input
• Unit alarm contacts
• Chilled liquid pump control
• Automatic reset after power failure
• Automatic system optimization to match operating
conditions
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