Specifications

FORM 150.72-NM1 (908)
115
JOHNSON CONTROLS
7
This message informs the operator that the chilled
liquid temperature is below the point (determined by the
setpoint and control range) that the micro will bring on a
system or that the micro has not loaded the lead system
far enough into the loading sequence to be ready to bring
the lag system “ON”. The lag system will display this
message until the loading sequence is ready for the lag
system to start.
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.
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.
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.
When this message appears, discharge pressure limiting
is in effect. The Discharge Pressure Limiting feature
is integral to the standard software control; however
the discharge transducer is optional on some models.
Therefore, it is important to keep in mind that this
control 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 automatically
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
discharge pressure drops to 85% of the unload pressure
and 10 minutes have elapsed.
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 pressure 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.
This message indicates that load limiting is in effect and
the percentage of the limiting in effect. This limiting
could be due to the load limit/pwm input, ISN or RCC
controller sending a load limit command.
If MANUAL OVERRIDE mode is selected, the STATUS
display will display this message. This will indicate 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 emergencies or for servicing. Manual override
mode automatically disables itself after 30 minutes.
S Y S 1 N O C O O L L O A D
S Y S 2 N O C O O L L O A D
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
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
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
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
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
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 %
M A N U A L
O V E R R I D E