JOHNSON CONTROLS
130
FORM 150.67-NM2
ISSUE DATE: 01/31/2019
SECTION 7 – UNIT CONTROL CENTER
S Y S 1 C O M P S R U N X
S Y S 2 C O M P S R U N X
The COMPS RUNNING message indicates that the
respective system is running due to demand. The “X”
will be replaced with the number of compressors in
that system that are running.
S Y S 1 A R T I M E R X X S
S Y S 2 A R T I M E R X X S
The anti-recycle timer message shows the amount of
time left on the respective systems anti-recycle timer.
This message is displayed when the system is unable to
start due the anti-recycle timer being active.
S Y S 1 A C T I M E R X X S
S Y S 2 A C T I M E R X X S
The anti-coincidence timer is a software feature that
guards against 2 systems starting simultaneously. This
assures instantaneous starting current does not become
excessively high due to simultaneous starts. The micro
limits the time between compressor starts to 1 minute
regardless of demand or the anti-recycle timer being
timed out. The anti-coincidence timer is only present
on two system units.
S Y S 1 D S C H L I M I T I N G
S Y S 2 D S C H L I M I T I N G
When this message appears, discharge pressure limit-
ing is in effect. The Discharge Pressure Limiting fea-
ture is integral to the standard software control; howev-
er the discharge transducer is optional on some models.
Therefore, it is important to keep in mind that this con-
trol will not function unless the discharge transducer is
installed in the system.
The limiting pressure is a factory set limit to keep the
system from faulting on the high discharge pressure
cutout due to high load or pull down conditions. When
the unload point is reached, the micro will automati-
cally unload the affected system by de energizing one
compressor. The discharge pressure unload will occur
when the discharge pressure gets within 10 PSIG (0.69
barg) of the programmed discharge pressure cutout.
This will only happen if the system is fully loaded and
will shut only one compressor off. If the system is not
fully loaded, discharge limiting will not go into effect.
Reloading the affected system will occur when the dis-
charge pressure drops to 85% of the unload pressure
and 10 minutes have elapsed.
S Y S 1 S U C T L I M I T I N G
S Y S 2 S U C T L I M I T I N G
When this message appears, suction pressure limiting
is in effect. The suction pressure limit is a control point
that limits the loading of a system when the suction
pressure drops to within 15% above the suction pres-
sure cutout. On a standard system programmed for 44
PSIG/3.0 Bar suction pressure cutout, the micro would
inhibit loading of the affected system with the suction
pressure less than or equal to 1.15 * 44 PSIG/3.0 Bar
= 50 PSIG/3.5 Bar. The system will be allowed to load
after 60 seconds and after the suction pressure rises
above the suction pressure load limit point.
S Y S 1 L O A D L I M I T X X %
S Y S 2 L O A D L I M I T X X %
This message indicates that load limiting is in effect
and the percentage of the limiting in effect. This limit-
ing could be due to the load limit/pwm input, ISN or
RCC controller sending a load limit command.
M A N U A L
O V E R R I D E
If MANUAL OVERRIDE mode is selected, the STA-
TUS display will display this message. This will indi-
cate that the Daily Schedule is being ignored and the
chiller will start-up when chilled liquid temperature
allows, Remote Contacts, UNIT switch and SYSTEM
switches permitting. This is a priority message and
cannot be overridden by anti-recycle messages, fault
messages, etc. when in the STATUS display mode.
Therefore, do not expect to see any other STATUS
messages when in the MANUAL OVERRIDE mode.
MANUAL OVERRIDE is to only be used in emergen-
cies or for servicing. Manual override mode automati-
cally disables itself after 30 minutes.
S Y S 1 P U M P I N G D O W N
S Y S 2 P U M P I N G D O W N
The PUMPING DOWN message indicates that a com-
pressor in the respective system is presently in the pro-
cess of pumping the system down. When pumpdown is
initiated on shutdown, the liquid line solenoid or EEV
will close and a compressor will continue to run. When
the suction pressure decreases to the suction pressure
cutout setpoint or runs for 180 seconds, whichever
comes first, the compressor will cycle off.
To Next Page
Loading...
