Johnson Controls SABROE Unisab III Control User Manual

After the level float switch has become low, this timer delays the closing of the oil return
valve draining the evaporator.
47. Oil return delay
For chiller use only.
At compressor start-up, this timer is used to delay the open/close function of the oil return
valve draining the oil separator.
48. Pump down
For chiller use only.
This timer controls the maximum time the pump down sequence can run after compressor
stop. Pump down is used when the Chiller DX expansion valve control is configured.
This pump down function, where the compressor runs with a closed expansion valve, lets the
compressor run until the suction pressure is below the ”pump down set point” or until the
pump down timer has run out, whichever comes first.
49. PMS delay
After compressor stop it is possible to delay the PMS Start request output signal within the
stated time.
This delay can e.g. be used for pump after-run.
50. Critical low oil circuit
For SAB 157HR compressors
This timer starts if the difference in pressure between oil pressure and discharge pressure ex-
ceeds 5.0 bar. A shutdown is issued if the timer runs out. See subsection 2.2.34. Critical oil
circuit pressure shutdown for more details about this shutdown.
51. Start rpm limiter
For SAB 157HR compressors
During start-up the speed for a SAB 157HR may be limited to 1,000 [rpm] if the internal suc-
tion pressure is too high. The start-up limiter will only be active at compressor start-up and it
can maximum be active for the time set in timer Start RPM limiter.
If the start-up limiter is still active when the Start RPM limiter timer runs out, a shutdown is
given and the compressor is stopped.
52. High internal pressure
For SAB 157HR compressors
This timer starts if the calculated internal pressure exceeds 100.0 bar. A shutdown is issued if
the timer runs out. See subsection 2.1.2. Measured and calculated pressure levels - screws,
Note 29.
53. Fan delay
For frequency controlled screw compressors.
After compressor stop, the electrical fan has an after run for the stated time.
54. Oil pump low alarm
For SAB 120→151, SAB 157 HR and 193→355 compressors with oil pump.
Set-up
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Engineering manual - Unisab III 1.10
001930 en 2014.09

Johnson Controls SABROE Unisab III Control Specifications

General

Brand	Johnson Controls
Model	SABROE Unisab III Control
Category	Control Systems
Language	English