QUANTUM™ HD COMPRESSOR CONTROL PANEL
OPERATION
090.040-O (MAR 12)
Page 76
creasing if necessary.
If the position reached 32% (2% prede
fi
ned
value) the Load signal would be proportion-
ally pulsed in an attempt to raise the value
back up above the 34%. If, even with the
Load signal being pulsed, the Slide valve
position continues to drop, it will be permit-
ted to do so until it reaches 30%, at which
time the Load signal will be turned fully on,
and will remain on until the Slide Valve po-
sition increase above the 30% value, where
the Load signal will again be proportionally
pulsed.
If set to 0%, this portion of the logic will be dis-
abled.
[Highest Capacity Slide Position to Permit
Starting]
– The Slide Valve position must be
equal to or less than this setpoint to allow the
compressor to start.
[Starting Period Before Permitting Capacity
Slide Increase]
– This setpoint indicates the
time period after the compressor goes to the
Running State that the Slide Valve will not be
allowed to load.
[Stopping Period For Capacity Slide Unload]
– When the compressor is commanded to stop,
the Slide Valve will unload for this period, or until
the Slide Valve is at or below the Highest Capac-
ity to Permit Starting setpoint.
CAPACITY SLIDE UNLOAD ASSIST
[Rate of Decrease]
- This control will break the
possible hydraulic lock between the slide stop
and slide valve that may occur, particularly with
large diameter rotors (283 & 355mm compres-
sors). If the Vi (volume ratio) is 4.8 or lower and
the slide valve is 100%, then the slide stop will
be given an increase command simultaneous to
the slide valve unload command. Once the slide
valve has moved by a value in percent that is
equal to the Capacity Unload Assist setpoint,
a decrease command will be given to the slide
stop while the slide valve continues to receive
a unload command. If the Vi or volume ratio is
greater than 4.8 and the slide valve is 100% the
slide stop will be given a decrease signal simul-
taneous with a slide valve unload signal. Once
the slide valve is seen to have moved by a value
in percent that is equal to the Capacity Unload
Assist setpoint, the slide stop will be allowed
to move back to the proper operating position
based on compression ratio.
LIQUID SLUGGING
Liquid Slugging Warning]
- This warning is
triggered from a sudden decrease in Discharge
Temperature that is greater than the Liquid Slug
Warning setpoint occurring in a
fi
ve (5) second
period of time. That is, if the Discharge Temper-
ature is 130 degrees F, and the Liquid Slugging
Warning setpoint is 10 degrees F, then a sudden
drop in Discharge Temperature from 130 to 120
degrees F within a
fi
ve second period will gener-
ate a warning condition.
[Liquid Slugging Shutdown]
- This shutdown is
triggered from a sudden decrease in Discharge
Temperature that is greater than the Liquid Slug-
ging Shutdown setpoint occurring in a
fi
ve (5)
second period of time. That is, if the Discharge
Temperature is 130 degrees F, and the Liquid
Slug Shutdown setpoint is 20 degrees F, then a
sudden drop in Discharge Temperature from 130
to 110 degrees F within a
fi
ve second period will
generate a shutdown condition.
PULL DOWN -
With this option enabled, the Suc-
tion Pressure can be slowly lowered in steps. Slowly
walking the pressure down prevents rapid drops in
system pressure that may cause boiling of refrigerant
in the system. The following selections are provided:
[Enable]
•
Disabled
- The Pull Down feature is ig-
nored.
•
Enabled
- The Pull Down feature will be
utilized.
[Capacity Slide Stop]
- The percentage of travel
that the Slide Valve is permitted to load upon
Compressor starting, and thereafter determined
by the Amount of Time setpoint. For example,
if this setpoint is 5%, and the Amount of Time
setpoint is 1 Minute, then the Slide Valve will be
permitted to load 5% of its stroke every minute,
until such time as the compressor has reached
capacity. It would take 20 minutes for the Slide
Valve to fully load to 100% at this rate. Once
capacity has been achieved, this function is ig-
nored, until such time as the compressor is re-
started.
[Wait Time]
- The amount of time between
when the Slide Valve is permitted to move. See
Capacity Slide Stop description.
BALANCE PISTON
[On]
[Off]
