Carrier AquaSnap 61WG Series Installation, Operation And Maintenance Instructions

Also see for AquaSnap 30WG Series: Operation instructions

Contents

Carrier AquaSnap 61WG Series Installation, Operation And Maintenance Instructions Manual pdf 44 page image

447 - 30WGA UNIT CONNECTIONS7.1 - Recommendations for the installation ofliquid chillers 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-cooled condensersas the chiller heat rejection system.The refrigerant circuit installation of an operational system is limitedto the connection of the air-cooled condenser inlet and outlet tothe 30WGA unit.The components such as the check valve (in the discharge line),moisture sight glass and solenoid valves are installed and wiredin the factory.The filter-drier is supplied with the unit and must be installedupstream of the solenoid valve on the liquid line.The TouchPilot Junior control system of the 30WGA unitsincorporates the logic to permit control of the different fan versions(fixed or variable-speed).To guarantee optimum and reliable performance of the units it isnecessary to comply with the regulations described below, whenthese units are connected to remote condensers:- Size the discharge and liquid line piping according to therecommendations in the following paragraphs (if necessary,install a double riser to ensure correct oil circulation in therefrigerant circuit).- Select a condenser with an integrated subcooler to obtain aminimum of 3 K subcooling at the inlet to the expansiondevice.- Install the filter drier supplied with the unit as close as possibleto the liquid line filter drier.- Install the outside air temperature sensor supplied near theair-cooled condenser- For units with remote condenser control (option 154), thesensor is supplied. The outside air temperature informationis required for correct operation of the complete system.Control of the remote air-cooled condenser using option 154- Connect the fan stages electrically to the control board, usingauxiliary electronic board AUX 1. To assign the fan stagesrefer to chapters 14 and 15 with the description of theanalogue and digital inputs and outputs.- Make the communication bus connection (twisted andshielded cable type for communication bus RS485) betweenthe specific electronic AUX 1 board, that must be integratedin the condenser control box and the unit control board.- The Touch Pilot Junior 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 first fanstage for operation at low ambient temperature at part loadand for condensers with few fans.ATTENTION: The air-cooled condenser must always be usedwith a subcooler. Normally 8 K subcooling at the condenseroutlet is recommended.7.2 - Piping installation and connectionOn all units release the holding charge pressure before openingthe circuit.Use the various valves and/or remove the safety cap from theconical Schrader valve supplied. Push in the valve tip to releasethe complete system holding charge (nitrogen).Preparation before unsoldering the liquid and discharge line plugs:- Remove all components that may be damaged during theunsoldering procedure- Pipe soldering: remove the cores from the conical Schradervalves near the area, remove the pipe collars, remove thecladding panels and the metal crossbars.All these components must be replaced before commissioningthe system.- Unsolder the plugs and prepare the pipes for connection.- Connect the liquid line to the system, install the filter drierupstream of the unit.- Make the high-pressure connections (discharge line) betweenthe unit and the condenser.- During these operations circulate and inert gas such asnitrogen in the pipes to prevent the formation of copper oxyde.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.