Johnson Controls FRICK QUANTUM LX Operation page 35

setpoint, for the shutdown time delay, the
compressor will shut down.
• [Start Differential Pressure Below] – The
compressor will be inhibited from starting if
the difference between the Discharge Pres-
sure minus the Suction Pressure is greater
than this setpoint.
High Discharge Pressure:
• [Load Inhibit] - The compressor Slide Valve
will be prevented from loading until the Dis-
charge Pressure is less than this setpoint.
• [Force Unload] - When the Discharge Pres-
sure is greater than or equal to this setpoint,
the compressor Slide Valve will be forced to
Unload.
• [Warning and delay] - If the Discharge
Pressure is greater than or equal to this set-
point, for the warning time delay, a warning
occurs.
• [Shutdown and delay] - If the Discharge
Pressure is greater than or equal to this
setpoint, for the shutdown time delay, the
compressor will be shut down.
• [Highest Capacity to Permit Starting] –
The Slide Valve position must be equal to or
less than this setpoint to allow the compres-
sor to start.
• [Starting Period Before Permitting Capac-
ity 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 Unload] –
When the compressor is commanded to
stop, the Slide Valve will unload for this pe-
riod, or until the Slide Valve is at or below
the Highest Capacity to Permit Starting set-
point.
• [Compressor Automatic Mode Minimum
Capacity] – When the compressor is Run-
ning and the Compressor Mode and Capac-
ity Modes are both in Automatic, the Slide
Valve will be loaded so as to keep the Ca-
pacity at or above this setpoint.
• [Capacity Unload Assist] – A drop down
menu is provided to either enable or disable
this feature. When enabled, this control will
break the possible hydraulic lock between
the slide stop and slide valve that may oc-
cur, particularly with large diameter rotors
(283 & 355mm compressors). If the Vi (vol-
ume ratio) is 4.8 or lower and the slide valve
QUANTUM™ LX COMPRESSOR CONTROL PANEL
OPERATION
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 set-
point, 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 simultaneous 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.
High Suction Pressure:
• [Load Inhibit] - The compressor Slide Valve
will be prevented from loading until the Suc-
tion Pressure is less than this setpoint.
• [Force Unload] - When the Suction Pres-
sure is greater than or equal to this setpoint,
the compressor Slide Valve will be forced to
Unload.
• [Warning and delay] - If the Suction Pres-
sure is greater than or equal to this setpoint,
for the warning time delay, a warning oc-
curs.
• [Shutdown and delay] - If the Suction Pres-
sure is greater than or equal to this setpoint,
for the shutdown time delay, the compres-
sor will be shut down.
Economizer Control – This is a digital output (mod-
ule 11 on digital board #1).
• [Economizer]
• Disabled – Output is off.
• Enabled – If the compressor is running,
the On When Above and Off When Be-
low setpoints take effect, and the Ca-
pacity is compared to these setpoints
to determine when to turn the output
on or off.
• Override – Used to turn the output off
if the Discharge Pressure < (suction x
1.6^k) plus the Override setpoint.
Economizer VI Control – When economizing, the
added volume of the gas that is entering the side port
needs to be accounted for in the VI calculation. Fail-
ure to do so would result in over-compensation and
high energy usage. When the compressor is running
and the Economizer output is energized, the follow-
090.022-O (MAY 12)
Page 35