Quantech QWC4, Installation Operation & Maintenance, Page: 102 / 156

QUANTECH
102
FORM QWC4-NM1 (221)
ISSUE DATE: 02/28/2021
SECTION 6 - OPERATION
MESSAGE DESCRIPTION
YYYYYYY LOW
ECONOMIZER
SUPERHEAT FAULT
This fault protects against excessive liquid refrigerant carryover from the economizer, in
cases which may be a result of EEV, sensor or other problems. It also protects the system
compressor from liquid refrigerant flooding back from the economizer feed line, in cases where
the economizer valve fails to close. This safety is ignored for the first five minutes of system run
time. If the economizer superheat falls below a programmable setpoint (0°F to 20°F, default 5°F
(0°C to 11°C, default 2.7°C)) for five minutes, the system or unit will shutdown. This fault causes
a lockout on the third fault in 90 minutes. YYYYYYY will show FAULT to indicate a system is in a
FAULT condition, and will restart when the 120 second anti-recycle timer times out; or will show
LOCKOUT, and the system will not restart until the operator clears the fault using the keypad.
YYYYYYY LOW EVAP
PRESS
This fault protects against operation with low refrigerant charge, which helps protect the chiller
from an evaporator freeze-up, should the system attempt to run with a pressure below freezing
for the application. When SMART FREEZE POINT PROTECTION is disabled, this safety fault
is set whenever the evaporator pressure is less than or equal to the programmable cutout, and
is released when the evaporator pressure becomes greater than the programmable cutout. This
fault causes a lockout on the third fault in 90 minutes. YYYYYYY will show FAULT to indicate a
system is in a FAULT condition, and will restart when the 120 second anti-recycle timer times out;
or will show LOCKOUT, and the system will not restart until the operator clears the fault using
the keypad. When SMART FREEZE POINT PROTECTION is enabled, this safety fault is set
whenever the evaporator refrigerant temperature is less than 25.0°F, and is released when the
evaporator refrigerant temperature becomes greater than or equal to 25.0°F. This fault causes
a lockout on the first fault. YYYYYYYY will show LOCKOUT and will not restart until the operator
clears the fault using the keypad.
YYYYYYY LOW EVAP
PRESS LCHLT
This safety fault causes a lockout on the first fault, and is bypassed for the first 10 minutes
of chiller run time. It is set if the leaving chilled liquid temperature is less than the evaporator
saturation temperature by at least 2.5°F or greater than the evaporator saturation temperature by
at least 25.0°F for at least 10 consecutive minutes. This fault is released when the chiller stops
running, or the leaving chilled liquid temperature is within - 2.5° F and + 25.0°F of evaporator
saturation temperature. YYYYYYY will show LOCKOUT, and the system will not restart until the
operator clears the fault using the keypad.
YYYYYYY LOW EVAP
PRESS REFRIG TEMP
This safety fault is bypassed for the first ten minutes of chiller run time and is available only
whenever the SMART FREEZE PROTECTION is enabled. This fault is disabled for glycol
applications. This fault causes a lockout on the first fault. This fault is set when the evaporator
refrigerant temperature or the evaporator saturation temperature is less than 32°F (0°C) and
the evaporator refrigerant temperature is at least 3.0°F (-16°C) above or below the evaporator
saturation temperature for at least 60 consecutive seconds. This fault is released when any
of the following is true: Chiller stops running, SMART FREEZE PROTECTION is disabled,
Evaporator refrigerant temperature is greater than 32°F (0°C), Evaporator saturation temperature
is greater than 32°F (0°C), and evaporator refrigerant temperature is within 3.0°F (-16°C) (plus
or minus) of the evaporator saturation temperature. YYYYYYY will show LOCKOUT, and the
system will not restart until the operator clears the fault using the keypad.
YYYYYYY LOW
MOTOR CURRENT
This fault shuts the system down with a ramped shutdown when the microprocessor detects the
absence of motor current (less than 10% FLA), indicating the compressor is not running. This
safety is ignored for the first 10 seconds of operation. YYYYYYYY will show FAULT to indicate a
system is in a FAULT condition, will restart when the condition clears, and the 120-second anti-
recycle timer times out. If three faults occur within 90 minutes, LOCKOUT will appear, and will not
restart until the operator clears the fault using the keypad.
TABLE 33 - SYSTEM SAFETIES FAULTS (CONT'D)