FORM 160.54-O1
ISSUE DATE: 9/10/2014
JOHNSON CONTROLS
192
SECTION 3 - DISPLAY MESSAGES
allowable number of seconds. If the Evaporator Refrig-
erant Temperature sensor RT7 is enabled, (using pro-
cedure in OptiView Control Center – Service Instruc-
tions (Form 160.54-M1)), this parameter is used as the
Evaporator Refrigerant Temperature and the freeze
threshold is 32.8°F. If RT7 is not enabled, the Evapo-
rator Refrigerant Temperature used is the Evaporator
Saturation Temperature, derived from the Evaporator
Pressure transducer and the freeze threshold is 34.0°F.
The total count is incremented once for every second
the Evaporator Refrigerant Temperature is below the
freeze threshold (but is never decremented below zero).
The number of seconds it will take the chilled liquid to
freeze is based on how far the Evaporator Refrigerant
Temperature is below the freeze threshold as follows:
number of seconds
to freezing
(4053.7)
freeze threshold – evap.
refrigerant temp.
=
Smart Freeze is activated only if the feature has been
enabled by a Service Technician (following instruc-
tions in OptiView Control Center – Service Instruc-
tions (Form 160.54-M1)) and the Leaving Chilled Liq-
uid Temperature Setpoint is less than 38.0°F.
Evaporator – Transducer Or Leaving Liquid
Probe
A possible defective Evaporator Pressure transducer
or Leaving Chilled Liquid temperature transmitter has
been detected. The pressure and temperature that these
devices are indicating are not in the correct relation-
ship to each other. The Control Center converts the
Evaporator Pressure to a Saturated Temperature value
and compares this value to the Leaving Chilled Liquid
temperature (difference equals chilled liquid temp mi-
nus evaporator saturated temp). The difference should
not be outside the range of –2.5°F to +25.0°F. If the
transducer and transmitter are accurate, the Evaporator
Saturated temperature should not be greater than 2.5°F
warmer nor greater than 25.0°F colder than the Leav-
ing Chilled Liquid Temperature. In order to initiate a
shutdown, the difference must be outside the acceptable
range continuously for 10 minutes. For Steam Turbine
drive applications, this check is bypassed for the first 20
minutes of chiller operation. The chiller can be started
after the Compressor Switch is placed in the Stop-Reset
(O) position.
Evaporator – Transducer Or Temperature Sensor
A possible defective Evaporator Pressure transducer or
Refrigerant Temperature Sensor has been detected. The
Control Center converts the Evaporator Pressure to a
Saturated Temperature value and compares this value
to the optional Evaporator Refrigerant Temperature
Sensor. If the difference between these temperatures
is greater than 3.0°F, continuously for 1 minute, this
shutdown is performed. This check is only performed
under the following conditions:
• Chiller has been running for at least 10 minutes
• Evaporator Refrigerant Temperature (RT7) has
been enabled by a Service Technician using in-
structions in OptiView Control Center – Service
Instructions (Form 160.54.M1)
• Not in Brine Cooling mode (If compressor appli-
cation other than “P”, applies only to Flash Mem-
ory Card version C.MLM.01.02 and later)
• Smart Freeze is enabled (If compressor applica-
tion other than “P”, applies only to Flash Memory
Card version C.MLM.01.05.xxx and later)
• Evaporator Temperature Sensor (RT7) or Evapora-
tor Saturation Temperature is indicating a temper-
ature of less than 32.0°F (If compressor applica-
tion other than “P”, applies only to Flash Memory
Card version C.MLM.01.05.xxx and later)
The chiller can be started after the temperatures are
within 3.0°F of one another and the Compressor Switch
is placed in the Stop-Reset (O) position.
Condenser – High Pressure Contacts Open
The contacts of the electro-mechanical high pressure
safety device, located on the condenser shell, have
opened because this device has detected a pressure:
• more than 204 PSIG (R134a)
• more than 265.0 (R22)
The contacts will automatically close when the con-
denser pressure decreases to:
• less than 160 PSIG (R134a)
• less than 205 PSIG (R22)
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