York ECO 2 50, Руководство пользователя

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YORK INTERNATIONAL
40
CONTROLS
A factory-mounted unit controller with a 4x20 character
alphanumeric display and user keypad shall be included
as standard. The controller and keypad shall be housed
inside the low-voltage compartment of the control/power
panel. On units with supply or exhaust VFDs, the VFD
keypads shall be located inside the same panel as the
unit controller and interface keypad. Control operating
data, setpoints, unit setup, configuration, service and
history shall all be accessible via a single key. A sys-
tem alarm LED shall indicate failures to the operator
with more detail provide in the menu screens. The user
interface shall function with a simple menu-driven dis-
play for easy access to unit data with integral time clock
for weekly and holiday scheduling. The unit keypad
shall include password protection to prevent unautho-
rized access and tampering with unit setpoints and con-
figuration.
A single terminal strip shall be provided for all thermo-
stat and customer hard-wired field connections.
Unit controls shall be completely factory packaged and
compatible with a room thermostat. Constant volume
units shall operate with a two (2) cool/two (2) heat ther-
mostat. Staging decisions shall be based upon the de-
viation of space temperature from set point and the rate
of change of the space temperature.
VAV units shall operate with a sensor in the supply air
stream for cooling operation. Staging decisions shall
be based upon the deviation of supply air temperature
from set point and the rate of change of the supply air
temperature.
Controllers shall have the following safeties (both VAV
and CV):
• High and low pressure cut-outs (one each refriger-
ant circuit)
• Minimum on time for compressors
• Delay between compressor stages
• Anti-short cycle delays (minimum off time) for com-
pressors and supply fan
• Cooling lockout at 40° F; 0° F if equipped for low
ambient operation
• Air flow proving switch requiring proper air flow for
cooling operation
ACCESSORIES AND OPTIONS
Full perimeter and partial perimeter roof curbs - 14”
high roof curb with wood nailer. Roof curb covers the
entire perimeter of the unit (full curb) or that portion of
the unit that has airflow (partial curb).
Supply Fan VFD Manual Bypass – provides full air-
flow in the event of a VFD failure.
Power Supply Connections – single-point power with
manual disconnect, and dual-point power wiring options
are available for various applications.
Supply air setpoint reset by outside air or space air
temperature - Allows VAV supply air setpoint to float
upward (saving energy) if the outdoor air temperature
or the space temperature is sufficiently low.
Supply Fan Isolation – the entire supply fan assem-
bly shall be isolated from the unit base with 2" deflec-
tion springs.
Supply and Exhaust Fan Motors – high efficiency
ODP, and standard and high efficiency TEFC motors
are available all meeting the Energy Policy Act of 1992
(EPACT).
Low Ambient Operation – a low ambient kit is avail-
able to control compressor head pressure via VFD con-
denser fan speed control. Head pressure control is
accomplished by monitoring head pressure with suc-
tion and discharge line pressure transducers rather than
less accurate temperature control.
ECONOMIZERS
Manual Damper Economizer – economizer is avail-
able with a manual damper adjustable between 0-25
percent.
Two-Position Damper Economizer – economizer is
available with a two-position damper with the open po-
sition adjustable between 0-25 percent. The operation
of the two-position economizer shall be based on oc-
cupancy; occupied is open, unoccupied is closed.
Guide Specifications
(continued)