Unit Controls
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 |
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When this message appears, suction pressure limiting is in effect. Suction Pressure Limiting is only available on units that have the suction pressure transducer in- stalled. If a low pressure switch is installed instead, suc- tion pressure limiting will not function.
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 suc- tion 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 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 % |
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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 or an ISN controller could be 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 STATUS display will display this message. This will indicate that the Daily Schedule is being ignored and the chiller will
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 af- ter 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 |
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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, the liquid line solenoid will close and a com- pressor will continue to run. When the suction pressure decreases to the suction pressure cutout setpoint, the compressor will cycle off. If pump down cannot be achieved three minutes after the liquid line solenoid closes, the compressor will cycle off.
FAULT STATUS MESSAGES
Safeties are divided into two categories - system safe- ties and unit safeties. System safeties are faults that cause the individual system to be shut down. Unit safe- ties are faults that cause all running compressors to be shut down. Following are display messages and expla- nations.
SYSTEM SAFETIES
System safeties are faults that cause individual systems to be shut down if a safety threshold is exceeded for 3 seconds. They are auto reset faults in that the system will be allowed to restart automatically after the fault condition is no longer present. However, if 3 faults on the same system occur within 90 minutes, that system will be locked out on the last fault. This condition is then a manual reset. The system switch (under OPTIONS key) must be turned off and then back on to clear the lockout fault.
62 | YORK INTERNATIONAL |
