FORM 155.21-O1 (615)
61
JOHNSON CONTROLS
2
Recovery Conditions
• If the chiller was in RUN status at the time of the
event, then when the refrigerant temperature at RT8
is greater than or equal to 37ºF (2.7
°C) and the unit
switch is taken to STOP/RESET position the chiller
initiates dilution then becomes ready to start.
• If the chiller was not in RUN status at the time of
the event, when the refrigerant temperature at RT8
is greater than or equal to 37ºF (2.7
°C) and the unit
switch is placed to STOP/RESET position the chiller
becomes ready to start.
Low Refrigerant Temp Digital LRT Opened
The digital low refrigerant temperature switch opened
(Shutdown = 33ºF/.6ºC). If the chiller was in RUN
status, the chiller will close valves and stop all pumps
except the chilled water pump run contacts.
Recovery Conditions
•
If the chiller was in RUN status at the time of the
event, then when the refrigerant temperature switch
closes (Reset = 37ºF/2.7ºC) and the unit switch is
taken to STOP/RESET position the chiller initiates
dilution then becomes ready to start.
• If the chiller was not in RUN status at the time of
the event, when the refrigerant temperature switch
closes (Reset = 37ºF/2.7ºC) and the unit switch is
placed to STOP/RESET position the chiller becomes
ready to start.
Low Motor Coolant Level -
MCFL Switch Opened
This safety shutdown occurs when the unit is equipped
with Franklin pumps has MCFL switch opened.
Recovery Condition
• Motor coolant flow switch closes and the
unit switch
is placed in the
STOP/RESET
position. If the unit
was running before the failure, it performs a dilution
cycle when the motor coolant flow switch closes.
Manual Restart After Power is Restored
The chiller has recovered the power supply and the
restart after power failure setpoint is set to MANUAL.
The chiller initiates a dilution cycle.
Recovery Condition
• The unit switch is taken to STOP/RESET position.
The chiller continues dilution if it was in progress
or becomes ready to start.
MCFL Switch Opened, LDC Interrupted -
Chk Cryst
This shutdown occurs when the motor coolant float
switch opens when the unit is performing a limited
dilution cycle (only applicable to units equipped with
Franklin pumps).
Ref Pump Overload Twice - Chk for Cryst
This safety shutdown occurs when the refrigerant pump
overload contacts recover the second time since the unit
was started. The unit is set in a stand by safety shutdown
condition.
Recovery Condition
• After it has been determined that crystallization has
not occurred, the unit can be restarted. To restart
the unit, press the UNIT switch to the STOP/RESET
position, then press the WARNING RESET key in
SERVICE access and then initiate a start.
Refrigerant Pump Overloads Opened
Refrigerant pump motor protector overload or thermal
switch contacts opened and the pump was running. If
the chiller was in RUN status, the chiller initiates limited
dilution.
Recovery Conditions
• If the chiller was in RUN status at the time of the
event and the event was the first such event since
last start: When the overload contacts close, the
unit performs dilution and then if the unit switch is
taken to STOP/RESET position the chiller becomes
ready to start.
• If the event was not the first solution pump overload
event since last start, the control activates the safety
shutdown “REF PUMP OVERLOAD TWICE-
CHK FOR CRYST”.
• If the chiller was not in RUN status at the time of
the event, when the overload contacts close, and the
unit switch is placed to STOP/RESET position the
chiller becomes ready to start.
