JOHNSON CONTROLS
16
FORM 155.21-O1 (615)
Limited Dilution Cycle
– A limited dilution cycle was
created for power failure situations when the unit is
connected to a stand-by generator. A limited dilution
will only operate the solution pump or generator pump
(Franklin pump 10E3 – 14F3 units only) for a four hour
time period to conserve energy. It will not operate the
chilled liquid pump or condenser tower water pump
during this period. If the condenser flow switch closes,
(indicating flow) the limited dilution cycle will termi
-
nate. If the chilled water pump flow switch closes, the
limited dilution cycle will continue. During a limited
dilution cycle, the unit will continue to monitor if the
fault condition has been cleared to switch to a normal
dilution cycle.
Short Dilution Cycle
– The short dilution cycle option
must be enabled under the “Setpoints” screen in Service
access level. Upon unit shut down, the software logic
will monitor the strong solution temperature taken at
RT10 and compare this to the solution concentration
crystallization point. The duration period of the short
dilution cycle will be as follows:
Concentration
Pumps
operation
duration
2SOL opening
duration
Less than 57%
60 seconds
N/A
57% - 59%
70 seconds
50 seconds
59% - 61%
110 seconds
90 seconds
61% - 63%
170 seconds
150 seconds
63% - 65%
200 seconds
180 seconds
Greater than 65%
230 seconds
210 seconds
Depending on the solution concentration, the 2SOL
(stabilizer) solenoid valve will open to allow refriger-
ant from the discharge side of the refrigerant pump to
mix with the solution returning from the generator to
accelerate the dilution process. This feature cannot be
enabled during a power failure. All pumps; solution,
refrigerant, generator (Franklin pumps 10E3 – 14F3
units only), condenser and chilled liquid will run during
a short dilution cycle.
Purge Process
The YIA OptiView
TM
control handles 4 purge operation
modes, they are Auto, Manual, Maintenance, and Re-
pair. The chiller continually separates non-condensables
to the purge tank, regardless of mode. If these
non-condensables are NOT removed from the system
they will collect in the absorber section and blanket the
tubes. This blanketing will prevent the tubes from mak-
ing the necessary mass transfer of refrigerant from the
evaporator section, thus reducing the units capacity.
The mode determines how to clear the purge tank.
•
Auto-purge mode enables the unit able to clear the
purge tank by itself and monitor its performance.
•
Manual purge mode allows the operator to clear the
purge tank when necessary.
•
Maintenance mode allows the operator to change
the purge pump oil.
Repair mode gives the service technician full freedom
for all purge device operation. It allows troubleshoot-
ing and also allows operation to purge directly from the
evaporator-absorber shell, which is helpful in the unit
start-up process.
To reduce the risk of injury, never oper-
ate the purge pump with the belt guard
removed!
Extreme caution must be taken when
performing a purge process. Never
allowing air to enter the unit at any
time.
The auto-purge system can start and
stop automatically; even when the unit
is NOT running.
Smart Purge
The smart purge system is a new addition to the YIA
chiller product line. Smart purge system features in-
clude:
• Purge warm-up setpoint. This setpoint will allow
the purge pump oil to warm-up before opening
8SOL. It can be programmed from 2 minutes to
20 minutes, default being 2 minutes. If the purge
pump was running within 50 minutes prior to an
additional start-up, the warm-up period will default
to 2 minutes.
• The YIA auto-purge trigger pressure will be
80mmHg Abs, it will evacuate the purge tank to
30mmHg Abs.
• Continuous monitoring of the purge pump perfor
-
mance.
• Continuous monitoring of the purge tank pressure.
• Excess purge warning
OptiView Control Center