Carrier 50TZ/YZ 024 Installation, Operation And Maintenance Instructions

Contents

38Table 7 - Pressure switch settingsCut-out Cut-in ResetHigh pressurestat *2844 kPa *1863 kPa AutomaticLow pressurestat *265 kPa *363 kPa Automatic* Factory-calibratedWARNING: Alteration of factory settings other than the designset-point, without manufacturer's authorisation, may void thewarranty.Operating limitsThese units have been designed to operate within the followinglimits:Table 8 - Cooling operationZone Air temperatureDry bulb Wet bulbIndoorMaximum +35°C +21°CMinimum +19°C +14°COutdoorMaximum +46°C -Minimum +19°C* -* With the optional head pressure control, the unit can operate with temperatures below 19°C.Table 9 - Heating operationZone Air temperatureDry bulb Wet bulbIndoorMaximum +27°C -OutdoorMaximum +24°C +18°CMinimum -15°C* -Control sequenceThe unit is started and stopped by the remote control N1. If theremote control N1 requires cooling or heating, the built-incompressor short-cycle protection starts counting 3 seconds.After this time (if high-low pressurestats, indoor and outdoorfan thermal protectors are not tripped) the unit starts up.OPTIONS/ACCESSORIES- Head pressure control (option/accessory)- Electric resistance heater (option/accessory)- Hot water coil (option/accessory)- Outdoor air filter (option/accessory)- Crankcase heater (option/accessory) - only for 50TZ and38FZ units.GENERAL MAINTENANCEATTENTION: Before starting any servicing or maintenanceoperation on the unit, make sure that the power supply hasbeen disconnected. A current discharge could cause personalinjury.In order to obtain maximum performance from the unit specialattention should be paid to the following points:- Electrical connections: The supply voltage should bewithin the limits permitted by the compressor. Ensure thatno faulty contacts exist in the terminal blocks, contactorboards, etc. Make sure that all the electrical connectionsare properly tightened, and that all the electricalcomponents (contactors, relays, etc) are firmly secured tothe corresponding rails.Pay special attention to the condition of the connectingcables between the control elements and the electrical box,and to that of the unit power supply cable. They shouldnot be twisted and there should be no slits or notches inthe insulation. Check the starting and runningconsumptions are within the limits specified in thecorresponding technical information.- Drainage: Frequently check that the drain is notobstructed, and that the condensate pan is clean and level.- Inlet filter: This should be cleaned periodically. Thefrequency depends on the purity of the entering air. Thefilter may be cleaned with a household vacuum cleaner, orby immersing it in water.- Refrigerant circuit: Ensure that there is no leakage ofrefrigerant or oil from the compressor. Check that the highand low side operating pressures are normal. Make surethat the coils are not dirty. If necessary a filter may beinstalled in the outdoor air inlet. Check for unusualcompressor noise.- Controls: Check the operation of all electric controls,high and low pressurestats, etc.SERVICELubricationBoth the motors and the fans have factory lubricated and sealedbearings, and need no further lubrication.The compressor has its own oil supply and oil should not beadded unless a leak has occurred.

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