Quantech QTC40160, Installation Operation & Maintenance

Page: 115 / 188

Section 7 - Operation
Quantech
115
Form QTC4-NM2
Issue date: 05/12/2023
7
R-513A
Suction pressure
Unloading
Suction Pressure is between
2.70 psig and 1.80 psig
0 Hz
Suction pressure 1.62 psig 1 Hz
Suction pressure 1.44 psig 2 Hz
Suction pressure 1.26 psig 3 Hz
Suction pressure 1.08 psig 4 Hz
Suction pressure 0.90 psig 5 Hz
Suction pressure 0.72 psig 6 Hz
Suction pressure 0.54 psig 7 Hz
Suction pressure 0.36 psig 8 Hz
Suction pressure 0.18 psig 9 Hz
Suction pressure cutout 10 Hz
Sensor failure cutout fault
The Sensor Failure Cutout prevents the system from
running when a critical sensor (transducer, level sen-
sor, or motor winding temp sensor) is not function-
ing properly and reading out of range. This safety is
checked at startup and will prevent the system from
running if one of the sensors has failed.
The sensor failure safety will also fault and shutdown
a system while in operation, if a safety threshold is ex-
ceeded or a sensor reads out of range (high or low).
Following is the Status display fault message.
SYS X YYYYYYYY SENSOR FAILURE:
ZZZZZZZZZZZZ
The X indicates the specific system.
YYYYYYYY will either indicate the system
is in a FAULT condition and will restart
when the fault clears, or “LOCKOUT”
after 3 faults and will not restart until the
operator clears the fault using the keypad.
ZZZZZZZZZZZ indicates the failed sensor as follows:
• SUCT PRESS
• OIL PRESS
• DSCH PRESS
• ECONOMIZER PRESS
• MOTOR TEMP X
A specific motor temperature sensor can be ig-
nored using the unit setup mode, if it fails. Report
any failure to Quantech service for investigation.
The start inhibit thresholds for each sensor are shown
in the following table:
Table 24 - Start inhibit sensor thresholds
Sensor Low
threshold High
threshold
Suction
transducer
0.3 VDC 4.7 VDC
Oil
transducer
0.3 VDC 4.7 VDC
Discharge
transducer
0.3 VDC 4.7 VDC
Motor temperature
Sensor
0ºF (0°C) 240ºF (116°C)
High motor temperature cutout fault
The High Motor Temperature Cutout prevents a
compressor from running when its motor temperature
is too high. A system will fault and shut down when
any compressor motor temperature sensor rises above
121°C (250°F). The system will be inhibited from start-
ing if its motor temperatures sensors indicate tempera-
tures above 116°C (240°F). If any single temperature
sensor is being ignored under the Unit Set-up Mode,
that sensor will not be used when evaluating motor
temperature. The following is a sample Status display
fault message:
SYS X YYYYYYYY HIGH MOTOR TEMP
The X indicates the system and YYYYYYY indi-
cates the system is in a FAULT condition and restarts
when the fault clears or LOCKOUT and does not
restart until the operator clears the fault using the
keypad.
System control voltage cutout fault
The System Control Voltage Cutout alerts the opera-
tor the 115 VAC Control voltage to one of the systems
is missing. This may be due to a system fuse that has
been removed or is blown. The affected system will
fault and shut down immediately when the 115 VAC
supply is lost.
The safety does not shut down a system if the UNIT
switch is OFF, which electrically removes the 115 VAC
to all systems. The safety is only used to indicate a situ-
ation where a single system is missing the 115 VAC.
The safety will not cause a lockout and the system fault
will reset when power is returned. The following is a
sample message:
Table 23 - Suction pressure load limiting/unloading,
cont'd