Carrier 61WG 020 Installation, Operation And Maintenance Instructions

Contents

316.5 - 24 V user power reserveAfter all possible options have been connected, the transformerensures the availability of a usable 24 VA or 1 A power reservefor the control circuit on site.7 - 30WGA UNIT CONNECTIONS7.1 - Recommendations for the installation of liquidchillers with remote condenserThe 30WGA units (split units for connection to air-cooledcondensers) have been specially designed to optimise theoperation of split system installations, using air-cooledcondensers as the chiller heat rejection system.The refrigerant circuit installation of an operational system islimited to the connection of the air-cooled condenser inletand outlet to the 30WGA unit.The components such as the check valve (in the dischargeline), moisture sight glass and solenoid valves are installedand wired in the factory.The filter-drier is supplied with the unit and must be installedupstream of the solenoid valve on the liquid line.The Pro-Dialog+ control system of the 30WGA unitsincorporates the logic to permit control of the different fanversions (fixed or variable-speed).To guarantee optimum and reliable performance of the unitsit is necessary to comply with the regulations described below,when these units are connected to remote condensers:• Size the discharge and liquid line piping according tothe recommendations in the following paragraphs (ifnecessary, install a double riser to ensure correct oilcirculation in the refrigerant circuit).• Select a condenser with an integrated subcooler to obtaina minimum of 3 K subcooling at the inlet to the expansiondevice.• Install the filter drier supplied with the unit as close aspossible to the liquid line filter drier.• Install the outside air temperature sensor supplied neart h e a i r - c o o l e d c o n d e n s e r .For units with remote condenser control (option 154),the sensor is supplied. The outside air temperatureinformation is required for correct operation of thecomplete system.Control of the remote air-cooled condenser using option 154• Connect the fan stages electrically to the control board,using auxiliary electronic board AUX 1. To assign thefan stages refer to chapters 14 and 15 with the descriptionof the analogue and digital inputs and outputs.• Make the communication bus connection (twisted andshielded cable type for communication bus RS485)between the specific electronic AUX 1 board, that mustbe integrated in the condenser control box and usingthe NRCP master board of the 30WG unit.• The Pro-Dialog+ control is used to configure the numberof fan stages and the fan type based on the air-cooledcondenser model used in the installation.• A fan speed controller may is recommended for the firstfan stage for operation at low ambient temperature atpart load and for condensers with few fans.ATTENTION: The air-cooled condenser must always beused with a subcooler. Normally 8 K subcooling at thecondenser outlet is recommended.7.2 - Piping installation and connectionOn all units release the holding charge pressure beforeopening the circuit.Use the various valves and/or remove the safety cap fromthe conical Schrader valve supplied. Push in the valve tip torelease the complete system holding charge (nitrogen).Preparation before unsoldering the liquid and discharge lineplugs:• Remove all components that may be damaged duringthe unsoldering procedure• Pipe soldering: remove the cores from the conicalSchrader valves near the area, remove the pipe collars,remove the cladding panels and the metal crossbars.All these components must be replaced before commissioningthe system.Components be removed before soldering• Unsolder the plugs and prepare the pipes for connection.• Connect the liquid line to the system, install the filterdrier upstream of the unit.• Make the high-pressure connections (discharge line)between the unit and the condenser.• During these operations circulate and inert gas such asnitrogen in the pipes to prevent the formation of copperoxyde.IMPORTANT: The condenser circuit piping must be inaccordance with good practices relating to the static supportand the thermal expansion of copper pipes.To ensure system vibration control, the collar positions onthe piping in the unit must not be changed. At the outlet ofthe refrigerant section there are pipe flange collars. It isimperative to tighten these collars to prevent vibrations andpossible breaks.