Carrier AquaEdge 19XRV series Operation, Maintenance And Installation Manual

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

Contents

79NOTE: Prior calibrations may have shifted the presentpre-calibration value from the center of this range. In this case,the limit of acceptable new values will be less than 15% in onedirection.If the ICVC fails to accept the high end calibration, thevalue will not change and the display will show “Higher ForceIn Effect.” This indicates that the sensor voltage is out of theacceptable range for the entered value. If this occurs with adifferential pair, one possible remedy is to swap the high end(inlet) and low end (outlet) transducers. In most cases this putsthe sensor voltage within the acceptable range.Each transducer is supplied with 5 vdc power from theCCM. Pressure transducer readings are derived from voltageratio, not absolute voltage, which compensates for anyreference voltage variation. If this power supply fails, atransducer voltage reference alarm is generated. If transducerreadings are suspected of being faulty, check the supplyvoltage, measured between the high and low (first and third)terminals of any transducer 3 terminal connection at the CCM.This is also displayed in CONTROL TEST under CCMPRESSURE TRANSDUCERS.Check Optional Pumpout System Controlsand Compressor — Controls include an on/off switch,a 0.5-amp fuse, the compressor overloads, an internal thermo-stat, a compressor contactor, refrigerant low pressure cut-out,and a refrigerant high pressure cutout. The high pressure cutoutis factory set to open at 185 psig (1276 kPa) and reset at140 psig (965 kPa). The low pressure cutout is factory set toopen at 7 psia (–15.7 in. HG) and close at 9 psia (–11.6 in. HG).Ensure the water-cooled condenser has been connected. Ensureoil is visible in the compressor sight glass. Add oil if necessary.See the Pumpout and Refrigerant Transfer Procedures andOptional Pumpout System Maintenance sections, pages 84 and92, for details on the transfer of refrigerant, oil specifications,etc.High Altitude Locations — Because the chiller is ini-tially calibrated at sea level, it is necessary to recalibrate thepressure transducers if the chiller has been moved to a highaltitude location. See the calibration procedure in the Trouble-shooting Guide section.Charge Refrigerant into ChillerThe standard 19XRV chiller is shipped with the refrigerantalready charged in the vessels. However, the 19XRV chillermay be ordered with a nitrogen holding charge of 15 psig(103 kPa). Evacuate the nitrogen from the entire chiller, andcharge the chiller from refrigerant cylinders.CHILLER EQUALIZATION WITHOUT A PUMPOUTUNITTo equalize the pressure differential on a 19XRV chillerwith the refrigerant isolated in one of the heat exchangers, usethe terminate lockout function of the CONTROL TEST on theSERVICE menu. This helps to turn on pumps and advises theoperator on proper procedures.The following steps describe how to equalize refrigerantpressure in an isolated 19XRV chiller without a pumpout unit.1. Access terminate lockout function on the CONTROLTEST screen.2.3. Slowly open the motor cooling isolation valve. Thechiller’s cooler and condenser pressures will graduallyequalize. This process takes approximately 15 minutes.4. Once the pressures have equalized, the cooler isolationvalve, the condenser isolation valve, and the hot gas isola-tion valve may now be opened. Refer to Fig. 35 and 36,for the location of the valves.CHILLER EQUALIZATION WITH PUMPOUT UNIT —The following steps describe how to equalize refrigerantpressure on an isolated 19XRV chiller using the pumpout unit.1. Access the terminate lockout function on the CONTROLTEST screen.2.3. Open valve 4 on the pumpout unit and open valves 1a and1b on the chiller cooler and condenser, Fig. 35 and 36.Slowly open valve 2 on the pumpout unit to equalize thepressure. This process takes approximately 15 minutes.4. Once the pressures have equalized, the discharge isola-tion valve, cooler isolation valve, optional hot gas bypassisolation valve, and the refrigerant isolation valve can beopened. Close valves 1a and 1b, and all pumpout unitvalves.The full refrigerant charge on the 19XRV chiller will varywith chiller components and design conditions, as indicated onthe job data specifications. An approximate charge may be de-termined by adding the condenser charge to the cooler charge.See the Physical Data section.CAUTIONThe transfer, addition, or removal of refrigerant in springisolated chillers may place severe stress on external pipingif springs have not been blocked in both up and downdirections. Failure to block springs in both up and downdirections could result in severe personal injury and equip-ment damage.CAUTIONAlways operate the condenser and chilled water pumpsduring charging operations to prevent freeze-ups. Damagecould result to equipment if condenser and chilled waterpumps are not operated during pumpdown or charging.CAUTIONWhen equalizing refrigerant pressure in the 19XRV chillerafter service work or during the initial chiller start-up, donot use the discharge isolation valve to equalize. Either themotor cooling isolation valve or a charging hose (con-nected between the refrigerant charging valves on top ofthe cooler and condenser) should be used as the equaliza-tion valve. Damage to the float valve could result.WARNINGWhenever turning the discharge isolation valve, be sure toreattach the valve locking device. This prevents the valvefrom opening or closing during service work or duringchiller operation, which could result in serious personalinjury.IMPORTANT: Turn on the chilled water and con-denser water pumps to prevent freezing.IMPORTANT: Turn on the chilled water and con-denser water pumps to prevent freezing.