Carrier AquaEdge 19XR series Start-up, Operation And Maintenance Instructions Manual

Also see for AquaEdge 19XR series: Installation instructions Start-up, operation and maintenance instructions

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Carrier AquaEdge 19XR series Start-up, Operation And Maintenance Instructions Manual Manual pdf 48 page image

48The schedules also can be overridden to keep the chiller inan occupied state for up to 4 hours, on a one time basis. See theTime Schedule Operation section, page 27.Figure 22 shows a schedule for a typical office buildingwith a 3-hour, off-peak, cool-down period from midnight to3 a.m., following a weekend shutdown. Holiday periods are inan unoccupied state 24 hours per day. The building operatesMonday through Friday, 7:00 a.m. to 6:00 p.m., and Saturdaysfrom 6:00 a.m. to 1:00 p.m. This schedule also includes theMonday midnight to 3:00 a.m. weekend cool-down schedule.NOTE: This schedule is for illustration only and is notintended to be a recommended schedule for chiller operation.Whenever the chiller is in the LOCAL mode, it uses Occu-pancy Schedule 01 (OCCPC01S). When the chiller is in theICE BUILD mode, it uses Occupancy Schedule 02 (OC-CPC02S). When the chiller is in CCN mode, it uses Occupan-cy Schedule 03 (OCCPC03S). The default setting for both LO-CAL and CCN schedules is OCCUPIED all of the time.The CCN SCHEDULE NUMBER is configured on theNET_OPT display screen, accessed from the EQUIPMENTCONFIGURATION table. See Table 3, Example 16. SCHED-ULE NUMBER can be changed to any value from 03 to 99. Ifthis number is changed on the NET_OPT screen, the operatormust go to the ATTACH TO NETWORK DEVICE screen toupload the new number into the SCHEDULE screen. SeeFig. 21.Safety Controls — The PIC II monitors all safety controlinputs and, if required, shuts down the chiller or limits theguide vanes to protect the chiller from possible damage fromany of the following conditions:• high bearing temperature• high motor winding temperature• high discharge temperature• low discharge superheat*• low oil pressure• low cooler refrigerant temperature/pressure• condenser high pressure or low pressure• inadequate water/brine cooler and condenser flow• high condenser water pressure drop (optional)• high, low, or loss of voltage• ground fault• voltage imbalance• current imbalance• excessive motor acceleration time• excessive starter transition time• lack of motor current signal• excessive motor amps• excessive compressor surge• temperature and transducer faults*Superheat is the difference between saturation temperature(CONDENSER REFRIGERANT TEMPERATURE) andsensible temperature (COMPRESSOR DISCHARGE TEM-PERATURE). The high discharge temperature safety mea-sures only sensible temperature.Faults or protective devices within the optional VFD canshut down the chiller.If the PIC II control initiates a safety shutdown, it displaysthe reason for the shutdown (the fault) on the ICVC displayscreen along with a primary and secondary message, energizesan alarm relay in the starter, and blinks the alarm light on thecontrol panel. The alarm is stored in memory and can beviewed on the ALARM HISTORY and ISM_HIST screens onthe ICVC, along with a message for troubleshooting. If thesafety shutdown was also initiated by a fault detected in themotor starter, the conditions at the time of the fault will bestored in ISM_HIST.To give more precise information or warnings on thechiller’s operating condition, the operator can define alert lim-its on various monitored inputs in the SETUP1 screen. A par-tial list of protective safety and alert limits is provided inTable 6. A complete list of alarm and alert messages is provid-ed in the Troubleshooting Guide section on page 99.Pump and Fan Control — The Carrier PIC controlsare designed to control when cooler and condenser waterpumps and tower fans are turned on and off. This is accom-plished through a series of relay contacts on the ISM within thestarter or optional VFD, and interface terminals are provided atISM terminal strip J9 (refer to the Carrier Installation Instruc-tions and certified drawings). If primary control of waterpumps and tower fans is provided by customer-installed devic-es, a parallel means for the Carrier controls to independentlyoperate the pumps must also be provided to protect againstfreeze-up.Shunt Trip (Option) — A main circuit breaker shunttrip device is provided standard as a safety trip with all unit-mounted starters, and is optional on other starters and someVFDs. When a shunt trip is provided, it is wired from an outputon the ISM to the associated coil on the shunt trip equippedmotor circuit breaker. The shunt trip is activated by ISM logic,based on values entered in the ISM_CONF table, under any ofthe following conditions:• Motor locked rotor amps limit exceeded• Starter locked rotor amps rating exceeded• Ground fault or phase-to-phase current fault limitexceeded (when that option is included)• Significant motor current detected more than 20 secondsafter a shutdown or otherwise when the chiller is off• 1M and 2M auxiliary contacts closed when the chiller isoff.In addition, starters may be designed to shunt trip based onother starter-specific conditions or features. For example, Ben-shaw solid-state starters include several such protective cir-cuits. The shunt trip is also activated if EVAPORATOR PRES-SURE drops below 0 psig (0 kPa). The Shunt Trip feature canbe tested using the Control Test feature.Function Loss Trip — The Function Loss Trip deviceis provided standard as a safety trip with all unit-mountedVFDs. When provided, the function loss trip is wired from anoutput on the ISM to the VFD regulator board on the functionloss terminal. The function loss trip is activated by ISM logic,based on values entered in the ISM _ CONF table.CAUTIONIf compressor motor overload occurs, check the motor forgrounded or open phases before attempting a restart.