Carrier Aquasnap 30RW Installation, Operation And Maintenance Instructions

Contents

Carrier Aquasnap 30RW Installation, Operation And Maintenance Instructions Manual pdf 31 page image

3111.5 - 30RW units without evaporator and condenserpump, three-way valve configuration for low outsidetemperature application30RW units can be supplied from the factory without evapo-rator and condenser pump. If year-round low-temperatureoperation is planned, the chiller will be installed with athree-way valve that is not supplied with the chiller.In this case Pro-Dialog Plus should be configured forthree-way valve system control from an analogue 0-10 voltoutput on the NRCP type master board. An adequatecondensing temperature will be maintained with constantcondenser flow rate. This configuration permits year-roundsystem operation down to -20°C outside temperature.Control and changeover of the fan stages are described inthe paragraph “Configuration of the number of fan stagesand automatic changeover of the fan stages” is identical inthis case.11.6 - Drycooler installationFor the drycooler installation follow professional guidelines.• Water pipe sizing• Maximum piping and shut-off valve pressure dropsbased on the available pressure of the 30RW pumps• Maximum drycooler elevation in relation to the chiller(safety valve at 4 bar on the 30RW water circuit).• Fan stage control (see “Fan stage control”).• Good positioning of the outside air temperature anddrycooler leaving water temperature sensors.12 - 30RWA UNIT OPERATION WITH REMOTE AIR-COOlED CONDENSER12.1 - Operating principle30RWA units are specially designed to optimise the opera-tion of split installations using air-cooled condensers as thechiller heat rejection system. The installation of an operationalsystem is limited to the connection of the air-cooledcondenser entering and leaving piping to the 30RWA unit.The Pro-Dialog Plus control system of the 30RWA unitsincorporates the logic to permit control of the different fanversions (single-circuit, dual-circuit, fixed and variable-speed fan, separate ventilation or interlaced ventilation atthe circuit level).12.2 - Master fanThe physical position of the air-cooled single- or dual-circuitair-cooled condenser with fixed or variable-speed fansdepends on the position of the leaving liquid refrigerantmanifold. In all cases there is always a so-called master fan.This is the fixed or variable-speed fan that is physically theclosest to the leaving liquid refrigerant manifold.This ensures optimum subcooling on the leaving condenserside, especially at part load. This is the first fan to start ineach circuit and the last fan to stop. A fan configurationwith fixed-speed fans permits year-round system operationdown to 0°C outside temperature.A fan configuration with a variable-speed master fan permitsyear-round operation down to -10°C outside temperature.12.3 - Dual-circuit condenser with separate ventilationand interlaced ventilationFor dual-circuit air-cooled condensers the most frequent andrecommended configuration is with an air-cooled conden-ser with completely independant circuits at fan level. Thisconfiguration is called “separate ventilation” by circuit.It is also possible to control ventilation of a dual-circuitair-cooled condenser where the fans are not independantby circuit. This is called “interlaced ventilation”.The Pro-Dialog Plus service configuration of the fansper-mits setting up these two dual-circuit air-cooledcondenser types.12.4 - Auxiliary electronic analogue input and outputand discrete output board (AUX1) for control of theair-cooled remote condenserThis is the same board as the one used in the drycoolers (seeparagraph “Auxiliary electronic analogue input and outputand discrete output board for control of the drycooler”).Refer to the assignment od the discrete output of the boardbased on the air-cooled condenser type installed (single-circuit, dual-circuit with separate ventilation, dual-circuitwith interlaced ventilation).See paragraph “Possible fan arrangements based on theair-cooled condenser type used in the installation”.0-10 V dc analogue outputs connectors J4 and J5:Used for master fan speed variation of circuits A and B ofthe air-cooled condensers for operation at low outsidetemperature.• Connector J6: Analogue inputs CH 11 for outsidetemperature sensors• Connector J9: Communication with the master basicboard of the 30RW unit.12.5 - Configuration of the number of fan stages andfan type based on the air-cooled condenser modelused in the installationPlease refer to the instructions in the Pro-Dialog Plus IOMfor the 30RW/30RWA units to carry out the parametersetting of the air-cooled condenser used in the installation:• Single-circuit or dual-circuit condenser• Use of speed variation on the master fan(s)• Dual-circuit condenser with separate or interlacedventilation• Number of fixed-speed fansBased on the parameter setting used, the arrangement of thediscrete and corresponding analogue outputs controllingthe fans will be activated by the control.The minimum configuration of the number of fan stages is2 for correct operation (2 fixed-speed or 1 variable-speed +1 fixed-speed fan).