York YCUL0045E, Установка, эксплуатация и обслуживание

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JOHNSON CONTROLS
89
FORM 150.63-NM8 (1020)
2
SYSTEM LEAD/LAG
(Discharge Air Temp Control Only)
Lead/lag between systems may be selected to help
equalize average run hours between systems on chillers
with 2 refrigerant systems. This may be programmed
under the OPTIONS key. Auto lead/lag allows auto-
matic lead/lag of the two systems based on average run
hours of the compressors in each system. Manual lead/
lag selects specifically the sequence in which the micro
starts systems. Systems in Suction Pressure Control act
independently based on the individual Suction Pressure
Control SETPOINTS.
COMPRESSOR LEAD/LAG
The compressors within a system rotate starts in se-
quence 1, 2 or 1, 2, 3 with wraparound. The longest-off
compressor in a system will start first, and the longest-
running compressor in a system will turn off first. When
unloading, the system with the most compressors on, un-
loads first. The lag system will shut down a compressor
first when equal numbers of compressors are operating
in each system. The micro will not attempt to equalize
run time of compressors in a system.
Once the second system has started a compressor, the
micro will attempt to equally load each system. Once
this occurs, loading will alternate between systems.
If Soft Start is enabled on European models with this
option, compressor lead/lag will function as outlined in
Option 12 under the Options key.
ANTI-RECYCLE TIMER
The programmable anti-recycle timer assures that sys-
tems do not cycle. This timer is programmable under the
PROGRAM key between 300 - 600 seconds. Whenever
possible, to reduce cycling and motor heating, the anti-
recycle timer should be adjusted to 600 seconds. The
programmable anti-recycle timer starts the timer when
the first compressor in a system starts. The timer begins
to count down. If all of the compressors in a circuit
cycle off, a compressor within the circuit will not be
permitted to start until the anti-recycle timer has timed
out. If the lead system has run for less than 5 minutes,
3 times in a row, the anti-recycle timer will be extended
to 10 minutes.
ANTI-COINCIDENCE TIMER
This timer is not present on single-system units. Two
timing controls are present in software to assure com-
pressors within a circuit or between systems, do not start
simultaneously. The anti-coincidence timer assures there
is at least a one minute delay between system starts on
2-circuit systems. This timer is NOT programmable. The
load timers further assure that there is a minimum time
between compressor starts within a system.
EVAPORATOR BLOWER CONTROL
The evaporator start contacts (CTB2 - terminals 23 - 24)
are energized when any of the following conditions are
true:
1. Any compressor is running
2. Daily Schedule is not programmed OFF and
Unit Switch is ON.
The contacts will not close if the micropanel has been
powered up for less than 30 seconds or if the contacts
have been closed in the last 30 seconds to prevent mo-
tor overheating. These contacts can be used to start the
evaporator blower and for all practical purposes, will
be running in a “constant fan” mode. However, if the
blower is desired to cycle with the compressors, then
cycling of the evaporator blower can be achieved by
using the “Run Contacts” located at CTB2 - terminals
25 to 26 for system 1, or CTB2 - terminals 27 to 28 for
system two (if applicable).
PUMPDOWN CONTROL
Each system has a pump-down feature upon shut-off.
Manual pumpdown from the keypad is possible by turning
off the respective system’s switch under the OPTIONS
key. On a non-safety, non-unit switch shutdown, all
compressors but one in the system will be shut off. The
LLSV will also be turned off. The final compressor will
be allowed to run until the suction pressure falls below the
cutout, or for 180 seconds, whichever comes first.