Carrier 30GX Installation, Operation And Maintenance Instructions

Also see for 30GX Series: Installation, operation and maintenance instructions Installation, operation and maintenance instructions

285.3 - Evaporator water pump controlThe evaporator water pump is started when the unit is in therunning mode described above or in delay at start-up mode (i.e.mode 7). Since the minimum value for the delay at start-up is 2minutes (configurable between 2 and 15 minutes), the pumpwill run for at least two minutes before the first compressorstarts. The pump is kept running for one minute after the unitgoes to stop mode. The pump keeps working when the unit isswitching from heating to cooling mode or vice-versa. It isturned off if the unit is shut down due to an alarm unless thefault is a frost protection error or risk of freezing.5.4 - Condenser water pump controlOnly available on water-cooled units.The condenser pump can be controlled by two modes, depend-ing on the configuration (only accessible by Carrier Service).1 - Control based on unit start/stop control. In this case it iscontrolled in the same way as the evaporator pump.2 - Control based on compressor status. In this case the pumpis activated at the same time as the first compressor. Itonly switches off when no compressor is activated.5.5 - Control pointControl point represents the leaving water temperature that theunit must produce.• In cooling mode: control point = active setpoint + reset• In heating mode: control point = active setpoint - reset5.5.1 - Active setpointTwo setpoints can be selected as active in cooling mode.Usually, the second setpoint is used for unoccupied periods orfor ice storage (medium or low brine unit). A single setpoint isavailable in heating mode.Depending on the current operating mode, the active setpointcan be selected with the operating type selector button, or withthe user’s volt-free contacts, or with network commands (seesection 4.2.7).5.5.2 - ResetReset means that the active setpoint is modified in such a waythat the capacity required by the unit is less (in cooling, thesetpoint is increased, and in heating it is lowered). Thismodification is in general a reaction to a drop in the load. Forthe PRO-DIALOG control system, the source of the reset canbe configured: it can be delivered either by an external 0-10 Vd.c. signal (e.g. outside temperature probe) or by the returnwater temperature. In both cases the reset parameters, i.e.slope, source and maximum value, are configurable in theSetpoints menu (see section 4.2.7) and are also independent forthe heating and cooling modes.5.6 - Demand limitGenerally, demand limit is used by an energy managementsystem in order to restrict the unit electricity consumption.The PRO-DIALOG control system for 30GX & 30HXprovides two methods of demand limit:5 - PRO-DIALOG PLUS CONTROL OPERATION5.1 - Start/stop controlThe unit is in stop mode and is not authorised to start up if atleast one of the following conditions is met:• The unit is in Local Off operating type (LOFF): mode 1 isactive.• The unit is in operating type Remote (rEM) and the controllerhas received a stop command over a volt-free contactconnected to the customer terminal block: mode 3 is active.• The unit is in operating type CCN (CCn) and either:- the controller has received a stop command over thenetwork: mode 2 is active; or- the controller has received a start command over thenetwork but start/stop control by volt-free contact isauthorised in CCN mode and the controller has receiveda stop command over a volt-free contact connected tothe customer terminal block: mode 2 is active.• The delay at start-up has not expired: mode 7 is active.• The unit is in the process of switching from heating tocooling mode: it has completely stopped before restarting.• CCN has commanded an emergency shutdown (EMSTOPactivated).• The unit is totally shut down due to an alarm.The unit is authorised to start if it is not in stop mode (seeabove) and if one of the following conditions is met:• The unit is in Local operating type (L-C1, L-C2, L-H, LC1r,LC2r): mode 4 is active.• The unit is in Remote operating type (rEM) and the controllerhas received a start command over a volt-free contactconnected to the customer terminal block: mode 6 is active.• The unit is in CCN operating type (CCn) and the controllerhas received a start command over the network, and either:- start/stop control by volt-free contact is not authorised inmode CCN: mode 5 is active; or- start/stop control by volt-free contact is authorised inmode CCN and the controller has received a startcommand over a volt-free contact connected to thecustomer terminal block: mode 5 is active.NOTE: In CCN operating mode, it is possible to authorise unitstart/stop over a volt-free contact connected to the customer’sterminal block. This configuration (which must be carried outby Carrier Service) is exceptional and generally only used forcontrolling a master unit in a master/slave grouping (seesection 5.18).5.2 - Heating/cooling selectionOn heat pumps, heating/cooling selection can be controlleddifferently depending on the active operating type:• Locally on the unit, using operating types L-C1, L-C2, LC1rand LC2r (for cooling) and L-H (for heating).• Remotely using the heat/cool selection volt-free contact whenthe unit is in Remote operating type (rEM).• Via a CCN command when the unit is in CCN operating type(CCn).The current heat/cool operating mode on the unit is indicatedby item 4 in the Information menu and by the heat/cool LEDson the summary interface.