YORK INTERNATIONAL
9
FORM 155.16-O3
DILUTION
The dilution cycle occurs at most shutdowns. The dilu-
tion cycle is required to prevent crystallization of the
lithium bromide solution. During the dilution cycle, the
solution (absorber and generator on 50 Hz Models YIA-
10E3 – YIA-14F3 with Franklin pumps); refrigerant; and
chilled and condenser water pumps are on and a 6
minute timer is initialized. Normally, the dilution cycle
terminates via the 6 minute timer. However, if the re-
frigerant level float switch is open, the dilution cycle
is terminated immediately; if the refrigerant tempera-
ture is less than or equal to 34°F (1.1°C), the dilution
cycle is terminated. If the chiller is shut down due to
the solution (absorber or generator on 50 Hz Mod-
els YIA-10E3 – YIA-14F3 with Franklin pumps) or re-
frigerant pump overloads or thermal switches, the
condenser water flow switch, the refrigerant tem-
perature sensor or cut-out switch, the chilled water
flow switch, or the motor coolant level float switch,
the dilution cycle shall be by-passed. Opening of any
of the previously listed contacts (in bold type) dur-
ing the dilution cycle also disables the dilution cycle.
If the solution (absorber or generator on 50 Hz Models
YIA-10E3 – YIA-14S with Franklin pumps) or refrigerant
thermal switches reclose, the dilution cycle is initiated
(one time only) if the strong solution temperature is above
136°F (57.8°C). However, if the strong solution tempera-
ture falls to <136°F (57.8°C) and the dilution cycle has
not begun, or if the overload contacts close a second
time, the unit shall initiate a safety shutdown with the
background message “TUE 9:47AM-PO-CHK FOR
CRYSTALLIZATION”. After decrystallization, if neces-
sary, the unit can be restarted by depressing the WARN-
ING RESET key in SERVICE mode. Either a power fail-
ure, unit start, or “CHK FOR CRYSTALLIZATION” mes-
sage clears the dilution cycle counter.
If the condenser water flow switch is open for at least 30
seconds while the system is running or during a dilution
cycle, the unit will shut down on a condenser water flow
switch failure. If the UNIT switch is in RUN position, the
start sequence is initiated if the switch recloses and the
strong solution temperature is above 136°F (57.8°C); if
the UNIT switch is in STOP/RESET position, the dilution
cycle is initiated. If the strong solution temperature falls
to <136°F (57.8°C), however and the condenser water
flow switch is open, the unit shall initiate a safety shut-
down with the background message “TUE 9:47AM
CDFL-CHK FOR CRYSTALLIZATION”. After decrystalli-
zation, if necessary, the unit can be restarted by de-
pressing the WARNING RESET key in SERVICE mode.
If the unit is shut down due to the low refrigerant tem-
perature cut-out at 33.0°F (.5°C) (provided by the low
refrigerant temperature switch or sensor), the chilled wa-
ter pump shall continue to run for a minimum of 30 min-
utes. The dilution cycle shall be initiated if the refrigerant
temperature rises to 37.0°F (2.8°C) and the strong solu-
tion temperature is above 136°F (57.8°C). If the strong
solution temperature falls to <136°F (57.8°C), and the
dilution cycle has not begun, the unit shall initiate a safety
shutdown; the background message shall be “WED
2:34PM-LRT-CHK FOR CRYSTALLIZATION”. After
decrystallization, if necessary, the unit can be restarted
by depressing the WARNING RESET key in SERVICE
mode.
Following a chilled water flow switch failure and subse-
quent unit safety shutdown, the chilled water pump con-
tinues to run for a minimum of 30 minutes. If the chilled
water flow switch recloses while the strong solution tem-
perature is above 136°F (57.8°C), the dilution cycle shall
begin. If however, the strong solution temperature falls
to <136°F (57.8°C) with the chilled water flow switch
open, the dilution cycle is bypassed and the background
message is “WED 2:34PM-FLS-CHK FOR CRYSTAL-
LIZATION”. After decrystallization, if necessary, the unit
can be restarted by depressing the WARNING RESET
key in SERVICE mode.
Following a power failure, if the unit had not previously
completed the dilution cycle and the strong solution tem-
perature is above 136°F (57.8°C) and the unit is config-
ured for manual restart after power failure (via removal
of Micro Board jumper J50), the unit shall begin the dilu-
tion cycle. However, if the strong solution temperature
falls to <136°F (57.8°C), and the dilution cycle has not
begun, the unit shall initiate a safety shutdown in which
the background message is “WED 2:34PM-PF-CHK
FOR CRYSTALLIZATION”. After decrystallization, if nec-
essary, the unit can be restarted by depressing the
WARNING RESET key in SERVICE mode. If the unit is
configured for auto restart after power failure (via inser-
tion of Micro Board jumper J50), the dilution cycle shall
be bypassed and a system start will occur.
If the unit is equipped with EPROM version A.02F.00,
following a motor coolant float switch safety shutdown, if
the float switch recloses while the strong solution tem-
perature is above 136°F (57.8°C), the unit shall begin
the dilution cycle. However, if the strong solution tem-
perature falls to <136°F (57.8°C) before the switch
recloses, the unit shall initiate a safety shutdown with
the background message “WED 2:34PM-MCFL-CHK
FOR CRYSTALLIZATION”. After decrystallization, if nec-
essary, the unit can be restarted by depressing the
WARNING RESET key in SERVICE mode. If unit is
equipped with EPROM version A.02F.01 or later, a dilu-
tion cycle is not resumed when the motor coolant switch
closes.
On units equipped with Buffalo pumps, the “REFRIG-
ERANT PUMP STARTUP DELAY” setpoint timer is dis-
Содержание MILLENNIUM YIA-HW-14F3
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