Carrier 38XTZ 007-024 Installation, Operation And Maintenance Instructions

35START-UPNecessary checks/precautions before start-up:- Confirm that the electrical power source agrees with theunit nameplate rating.- Ensure that the power connections between speed andthermostat have been made and correctly tightened.- Check that there are no refrigerant leaks in the solderedrefrigerant lines, and that the refrigerant and oil chargesare correct.- Check the 40ABZ/ALZ drain connection and that thewater is drained correctly.- Ensure that the unit is level and well-supported.- Check for proper fan rotation direction- Check the condition of the ductwork in case damage hasoccurred during installation.- The air filter should be clean and in place.- All the panels should be fitted and firmly secured with thecorresponding screws.- Make sure that compressors float freely on the mountingsprings.WARNING: The compressors are mounted on vibrationisolators. Do not loosen or remove the support mountingbolts.IMPORTANT: Actual start-up should only be done under thesupervision of a qualified refrigeration mechanic.Initial checksWith the unit in operation, ensure that the values shown on thehigh and low pressure gauges are within the normal limits. It isadvisable to simulate unit shutdown due to high and lowpressure, in order to make sure that the pressurestats workproperly. To do so, proceed as follows:- High pressure shutdown: Completely cover the outdoorair inlet, or disconnect the outdoor fan and motor. The unitshould stop at a pressure of 2844 kPa.- Low pressure shutdown: Cover the indoor air inlet, ordisconnect the indoor fan and motor. Observe the lowpressure gauge. The unit should stop at a pressure of 265kPa.The pressure switches are automatically reset. As this takessome time, the unit will stop, the pressures will equalise, andthen the unit will be reset and will start up again.Check that the motor and compressor consumptions areapproximately the same as those shown in the fan performancecurves and in the cooling capacity tables, for the unit operatingconditions (indoor and outdoor temperatures, air flow and staticpressures, based on the speed, etc.).UNIT COMPONENTSThe 38XTZ and 40ABZ/ALZ units incorporate the followingcomponents:- Three-phase hermetic reciprocating compressors withinternal thermal protection in the 38XTZ units.- Refrigerant-to-air heat exchangers (evaporators andcondensers) made of copper tubes and pre-treated, water-resistant aluminium fins.- All-copper refrigerant circuit. R-407C refrigerant controlin the 40ABZ/ALZ indoor units using thermostaticexpansion valves or throttle valves depending on themodel.- High and low pressure switch and filter drier (38XTZ).- Fan high pressure switch (38XTZ 014).- Soldered copper refrigerant connection lines at the unitoutlets.- Complete internal wiring. Main on/off disconnect switchin the 38XTZ outdoor units. These units also include thecomplete electrical boxes with compressor and indoor fanmotor contactors, transformers (depending on the model)and other components. Thermomagnetic disconnectswitches for compressors and fan motors.- Master Link I electronic control board for sizes 38XTZ016 to 024.- Fans:The 40ABZ/ALZ indoor units have centrifugal fans drivenby three-phase motors with adjustable belt-pulley drives.The 38XTZ outdoor units have direct-drive propeller fans.- Thermal and acoustical insulation. Flexible shockabsorbers in all moving components.- Air filters in the 40ABZ/ALZ indoor units.- Pre-painted galvanised sheet steel casings.DESCRIPTION OF UNIT PROTECTION DEVICESThe unit includes the following compressor protection devices:- Internal compressor protection device for all 38XTZunits to avoid superheat.- Short-cycle protection standard for units 38XTZ 007-014.- Short-cycle protection included on the Master Link I mainelectronic board for units 38XTZ 016-024- Indoor fan motor thermomagnetic switch in the 38XTZunit control box.- Thermomagnetic compressor and indoor fan motordisconnect switch, in the 38XTZ unit control box.- High pressurestat: This protects the unit against excessivecondensing pressure.The high pressurestat has factory-fixed non-adjustablesettings. To check, see section Initial checks.