York Millennium YCAS 310, Установка, эксплуатация и обслуживание

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FORM 201.10-NM3
65
YORK INTERNATIONAL
3 COMPRESSOR CHILLER (YCAS 310-380)
LEAD/LAG COMPRESSOR SELECTION
The Chiller may be set up for AUTO or MANUAL Lead/
Lag. This is accomplished by properly configuring the
S1 Dip Switches on the Microprocessor Board. Details
for configuring the switches are discussed in the DIS-
PLAY KEY Section 3.7 under “OPTIONS KEY AND DIP
SWITCH SETTINGS.”
When AUTO Lead/Lag is utilized, the micro attempts
to balance run time between the three compressors. A
number of conditions can occur which will prevent this
from happening. Factors determining lead/lag selec-
tion and the resulting lead/lag determination are dis-
cussed below:
1. The micro automatically defaults the lead to SYS 1
and the lag to SYS 2 if both compressors are ready
to start (Anti-recycle Timers timed out) and compres-
sors have equal run time.
2. If all compressors are ready to start (Anti-recycle
Timers are timed out), the compressor with the low-
est run hours will start first.
3. If all compressors are waiting to start (Anti-recycle
Timers are not timed out), the micro will assign the
lead to the compressor with the shortest anti-recycle
time in an effort to provide cooling quickly.
4. If the lead compressor is locked out, faulted and
waiting to restart, SYS switch on the micro board is
off, or a run permissive is keeping an individual sys-
tem from running, the lag compressor is swapped to
the lead. This is true regardless of whether the lag
compressor is on or off.
In Manual Lead/Lag Mode (See Section 8.1 and 3.7,
Switch 7), the sequence of operation is selectable. Af-
ter selecting the lead compressor, the micro will deter-
mine the starting sequence of the remaining two com-
pressors. This sequence is shown below. These se-
quences will be followed as long as anti-recycle timers
and safeties do not prevent it.
4 COMPRESSOR CHILLER YDAS (410-490)
LEAD/LAG COMPRESSOR SELECTION
The Chiller may be set up for AUTO or MANUAL Lead/
Lag. This is accomplished by properly configuring the
S1 Dip Switches on the Microprocessor Board. Details
LEAD
SECOND THIRD
COMPRESSOR
COMPRESSOR COMPRESSOR
SELECT
1 2 3
2 3 1
3 1 2
for configuring the switches are discussed in the DIS-
PLAY KEY Section under.
When AUTOis utilized, the micro attempts to balance
run time between the two compressors in either the
Master or
Subordinate
modules. A number of con-
ditions can occur which will prevent this from happen-
ing. Factors determining lead/lag selection and the re-
sulting lead/lag determination are discussed below:
1.
The micro automatically defaults the lead to SYS 1
or 3 and the lag to SYS 2 or 4 if both compressors in
either the Master or
Subordinate
modules, are
ready to start (Anti-recycle Timers timed out) and
compres-sors have equal run time.
2.
If all compressor are ready to start in a module (Anti-
recycle Timers timed out), the compressor with the
lowest run hours will start.
3.
If all compressors are waiting to start in a module
(Anti-recycle Timers are not timed out), the micro
will assign the lead to the compressor with the short-
est anti-recycle time in an effort to provide cooling
quickly.
4.
If the lead compressor in a module is locked out,
faulted and waiting to restart, SYS switch on the
micro board is off, or a run permissive is keeping an
individual system from running, the lag compressor
is swapped to the lead. This is true regardless of
whether the lag compressor is on or off.
If MANUAL Lead/Lag is selected, an external “dry” con-
tact (switch) must be wired into the “Master” module
(Fig. 1.13). This contact is field supplied. With the con-
tact open, SYS 1 or 3 is placed in the lead. When the
contact is closed, SYS 2 or 4 will be the lead system.
Selection of the lead compressor on the Master mod-
ule defines the lead compressor on the
Subordinate
module. This lead compressor on the
Subordinate
module is defined by the Master lead comp2.
Thus, if System #1 is the lead on the Master module,
System #3 will be the lead on the
Subordinate
module. If System #2 is the lead on the Master
module, System #4 will be the lead on the
Subordinate
module. The position of the
Subordinate
module microboard S1 switch 7 (lead/
lag) is ignored.
MANUAL Lead/Lag selection will be automatically over-
ridden by the micro to allow the lag compressor to au-
tomatically become the lead any time the selected lead
compressor shuts down due to a lock-out, lead system
faults and is waiting to restart, lead system switch on
the micro board is in the OFF position, or if a run per-
missive is keeping the lead of the system off. Auto-
matic switchover in the MANUAL mode is provided to
try to maintain chilled liquid temperature as close to
setpoint as possible.