Carrier 30XA Operation Instructions Manual

Carrier 30XA Operation Instructions Manual Manual pdf 31 page image

317.18 - Variable speed fans (option 17)Air-cooled.units.fitted.with.the.variable.speed.fans.option.allow for reducing the total unit consumption by adjustingthe fan speed to the current operating conditions.The control determines the optimum fan speed based on thecurrent compressor capacity, outdoor air temperature, andleaving water temperature.7.19 - Evaporator heater option (30XA)The evaporator heater protects the evaporator against frostwhen the unit is stopped at low ambient air temperature. Theheater is activated in the case of low outdoor air temperatureconditions.7.20 - Free cooling option (30XA)In air-cooled units only, this option allows for the direct useof low outdoor air temperature to cool the water circuitwithout activating the compressors.The direct-expansion free cooling system uses the principle ofthe natural migration of the refrigerant from the evaporator tothe condenser.The fans and a refrigerant pump ensure the transferof the liquid refrigerant from the condenser to the evaporator,which accounts for low power consumption.The free cooling option enables automatic operation as wellas combined operation of mechanical cooling (compressoroperation) and free cooling (FREECOOL – Free cooling).The control determines which circuit is allowed to run freecooling. Each refrigerant circuit can operate independently.Cooling operation may be performed in the followingcombinations:• two circuits in mechanical cooling• two circuits in free cooling• one circuit in mechanical cooling and one circuit infree coolingThe free cooling option is available for dual-circuit units. Itrequires the installation of SIOB board that controls theoperation of the motorised mechanical changeover valvesand the operation of the refrigerant pump.Free cooling option is enabled based on the following criteria:• The temperature difference between the outdoor airtemperature and the controlled water temperature.The.threshold.can.be.configured.by.the.user.(GEN_CONF.–.General.Configuration)• The maximum operating time in free cooling (FullLoad Timeout) when the water temperature setpointis not reached (Full Load Timeout, GEN_CONF –General.Configuration)7.21 - Dry cooler option (30XW)30XW units may come with the dry cooler option that enablesthe control of a Carrier dry cooler.The chiller and the dry cooler have to be connected througha LEN RS-485.7.22 - Hydronic kit option (30XA)The hydronic kit option allows for continuous monitoring ofthe.water.flow.rate.Hydronic kit option provides the following parameters:• Inlet and outlet water pressure (PUMPSTAT in theMain menu)•. Evaporator.flow.rate• Evaporator capacityThe. water. flow. rate. is. based. on. the. pressure. difference.between the evaporator inlet and outlet pressures and theevaporator pressure drop curves.The.evaporator.capacity.is.calculated.according.to.the.flow.rate, the water constant, and the difference between theentering and leaving evaporator water temperature.7.23 - 30XA-ZE and 30XW-ZE units (HFO)The Touch Pilot system may also control air-cooled and water-cooled units with R-1234ze refrigerant (HFO).Please note that this option comes with advanced electrical boxfan protection. In the case of the electrical box fan failure, theunit is shut down and alarm 10100 is triggered.7.24 - High condensing temperature option (30XW)7.24.1 - R134a configurationFor water-cooled units only, the economizer enables theincrease of the maximum condensing threshold. This meansthat the saturated condensing temperature can reach amaximum of 63°C (145°F) compared with a maximum of 50°C(122°F).for.units.that.are.not.fitted.with.this.option.7.24.2 - HFO configurationFor HFO units (30XW units with R-1234ze refrigerant), thehigh condensing option authorizes the saturated condensingtemperature to reach a maximum of 70°C (158°F) comparedwith.a.maximum.of.55°C.(131°F).for.units.that.are.not.fitted.with this option.7.25 - Maximum condenser leaving watertemperature option (30XW)For water-cooled units only, this option allows the user tolimit the condenser leaving water temperature to 45°C(113°F) and enables to limit the current absorbed by thecompressor. When the condensing temperature reaches 44°C(111°F), the increase in the compressor loading is stopped.When the temperature exceeds 45°C (113°F), the compressoris unloaded.