McQuay AGZ 030AM, Руководство по эксплуатации продукта

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44 AGZ 030A through 065A Product Manual AGZ-2
Global UNT microprocessor based control that accomplishes unit capacity control
by 4-stage cross-circuit compressor cycling based on leaving chilled water
temperature. Set point and control band shall easily field adjusted and anti-cycling
and stage delay relays are to be included. Safety controls shall include low and high
refrigerant pressure safeties, low evaporator flow, sensor failures, and evaporator
freeze protection. Motor protection shall include phase voltage, volts ratio, and
solid state compressor motor protection. The controller shall be equipped with a
Zone Terminal option that provides an onboard, hand-held, or remote mounted LCD
display of unit operating parameters and adjustment of any optional controls.
- OR -
MicroTech microprocessor control with a 12 key keypad and 2-line, 16 character
backlit liquid crystal display operator interface. The controller shall continuously
perform self diagnostic checks on all system temperatures, pressures, and safeties,
and automatically shut down a circuit or the entire unit at fault conditions. The
cause, time, and date of the occurrence shall be recorded and displayed along with
availability to view the seven previous incidents.
The controller shall take proactive measures to stay on-line for non-critical
abnormalities; staging down capacity, activating a pre-alarm signal and automatically
switching to the alarm menu on the display. These pre-alarms shall be self-clearing
when the off-condition is corrected.
Critical shutdown alarms such as high condenser pressure freeze protection, and low
evaporator pressure shall be manual reset and cleared at the keypad to resume
operation.
F The refrigerant discharge pressure shall be controlled by a FanTrol system
that cycles condenser fans based on discharge pressure and shall be operational 40
°
F
(4.4
°
C).
- OR -
The refrigerant discharge pressure shall be controlled by a SpeedTrol control
employing both fan cycling and fan speed control and allow operation to
0
°
F (-18
°
C).
G. The unit base and coil supports shall be fabricated from heavy gauge steel
and painted with weatherproof paint. Incidental supports may be galvanized.