Quantech QCC2015CEE Installation, Operation And Maintenance Manual page 106

SECTION 7 – UNIT CONTROLS
S Y S 1 C O M P S
S Y S 2 C O M P S
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 Z O N E
S Y S 2 Z O N E
These messages indicate that the zone thermostats
for system 1 and system 2 are open. These messages
will only be displayed when the control mode is pro-
grammed for Suction Pressure
S Y S 1 A R
S Y S 2 A R
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
S Y S 2 A C
The anti-coincidence timer is a software feature that
guards against two systems starting simultaneously.
This ensures instantaneous starting current does not be-
come excessively high due to simultaneous starts. The
microboard 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
S Y S 2 D S C H
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 microboard will auto-
matically unload the affected system by de energizing
one compressor. The discharge pressure unload will
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R U N X
R U N X
T H E R M O F F
T H E R M O F F
T I M E R X X S
T I M E R X X S
T I M E R X X S
T I M E R X X S
L I M I T I N G
L I M I T I N G
occur when the discharge pressure gets within 15 psig
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 load-
ed, discharge limiting will not go into effect. Reload-
ing the affected system will occur when the discharge
pressure drops to 85% of the unload pressure and 10
minutes have elapsed.
S Y S 1 S U C T
S Y S 2 S U C T
When this message appears, suction pressure limit-
ing is in effect. The suction pressure limit is a control
point that limits the loading of a system when the suc-
tion pressure drops to within 15% above the suction
pressure cutout. On a standard system programmed
for 80 psig/5.52 Bar suction pressure cutout, the mi-
croboard would inhibit loading of the affected system
with the suction pressure less than or equal to 1.15 x 80
psig/5.52 Bar = 92 psig/6.34 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
S Y S 2 L O A D
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 show this message. This will indicate
that the Daily Schedule is being ignored and the unit will
start-up when chilled liquid temperature allows, Remote
Contacts, UNIT switch and SYSTEM switches permit-
ting. 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 MANU-
AL OVERRIDE mode. MANUAL OVERRIDE is only
to be used in emergencies or for servicing. Manual over-
ride mode automatically disables itself after 30 minutes.
Form QCC2-NM1
Issue Date: 5/20/2021
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