Carrier 30XA080-500 Controls, Start-up, Operation, Service And Troubleshooting Instructions

Also see for 30XA325: Installation instructions Installation instructions

Carrier 30XA080-500 Controls, Start-up, Operation, Service And Troubleshooting Instructions Manual pdf 52 page image

Action Taken -- None.Termination -- None.Possible Causes -- This mode is in effect only due to pro-grmnming options.MODE 27 (MD27) -- High Pres Override CirAMODE 28 (MD28) -- High Pres Ovemde CirBMODE 29 (MD29) -- High Pres OveMde Cir CCriteria for Mode -- Tested when the circuit is ON. Theappropriate circuit mode will be active if the discharge pressurefor the circuit, Discharge Pressure Circuit A (Pressure---)PRC.A---)DPA), Dischalge Pressure Circuit B (Pressure--+PRC.B--+DP.B), or Discharge Pressure Circuit C (Pressure--+PRC.A--+DP.C), is greater than the High Pressure Threshold(Cotffiguration -_SER V--_HP. TH).Action Taken -- The capacity of the affected circuit will bereduced. Two minutes following the capacity reduction, the cir-cuit's saturated condensing temperature (SCT_+2) is calculatedand stored. The affected circuit will not be allowed to addcapacity for at least 5 minutes following the capacity reduction.If after 5 minutes, the circuit's saturated condensing tempera-ture is less than SCTt+: -3 ° F (1.7 ° C), and then if required,percent capacity will be added.If additional capacity is required, the control will look forother circuits to add capacity.Termination -- This mode will terminate once the circuit'ssaturated condensing temperatme is less than SCTt+ 2 -3 ° F(1.7° c).Possible Causes --If this condition is encountered, see Possi-ble Causes for Alarm A1.03. on page 80.MODE 30 (MD30) -- Low Superheat Circuit AMODE 31 (MD31 ) --Low Superheat Circuit BMODE 32 (MD32) -- Ix_w Superheat Circuit CCriteria for Mode -- Tested when the circuit is ON. The ap-propriate cimuit mode will be active if the circuit's superheat(discharge gas temperature- SCT) is less than 18° F (10 ° C).Action Taken -- No additiomd capacity will be added until thecircuit's supedaeat is greater than 18° F (10 ° C).The control will look for other circuits to add capacity ifadditional steps of capacity are required.Termination -- This mode will terminate once the affectedcircuit's superheat is greater than 18° F (10 ° C).Possible Causes -- If this condition is encountered, see Possi-ble Causes for Alarms R 11, R 12 and R 13 on page 76.MODE 33 (MD33) -- High Compressor Current Circuit AMODE 34 (MD34) -- High Compressor Current Circuit BMODE 35 (MD35) -- High Compressor Current Circuit CCriteria for Mode -- Tested when the circuit is ON with atleast one compressor ON. The appropriate circuit mode will beactive if the circuit's current is great than 79% of MTA valuefor the compressol:Action Taken -- No additional circuit capacity will be addedif the circuit's current is greater than 79% of MTA value for thecompressoEIf additional capacity is required, the control will look forother circuits to add capacity.Termination -- This mode will terminate once the affectedcircuit compressor current is less than 79% MTA value.Possible Causes --If this condition is encountered, see Possi-ble Causes for Alarms R 11, R 12 and R 13 on page 76.Sensors -- _ae electronic control uses up to 17 therlnistorsto sense temperatures and up to 12 transducers to sensepressure for controlling chiller operation. These sensors areoutlined below.THERMISTORS (Tables 29-30B)-- Thermistols that memonitoring the chiller's operation include: Cooler EnteringW_lter. Cooler Leaving Wato: Du;d Chiller Leaving Watel:Complessor Suction Gas Temperature, Compressor DischargeGas Temperature, Economizer Temperature, Complessor MotorTemperature, and Outdoor Air Temperature Thermistols. Thesethermistors me 5 k_2 at 77 F (25 C) and _u'e identical in tempera-ture versus resistance. The Space Temperature Thermistor is10 k_2 at 77 F (25 C) and has a diffoent temperature vs.resistance.Cooler Leaving Water Sensor -- On all sizes, this thermistoris installed in a friction fit well in the leaving water nozzle ofthe coolo: See Fig. 26 and 27.Cooler Entering Water Sensor -- On all sizes, this thermistoris factory-installed in a friction fit well in the entering waternozzle of the coolel:Compressor Return Gas Temperature-- On all sizes, thisthermistor is factolT-installed in a friction fit well located onthe compressor of each circuit. Thele is one thermistor for eachcircuit.Compressor Discharge Gas Temperature -- On _dl sizes, thisthermistor is factory-installed in a friction fit well located in thedischarge end of the compressor for the circuit. There is onethermistor for each circuit.Economizer Temperature- On all sizes, this thermistor isfactory-installed in a friction fit well located in the economizerline for the circuit. There is one thermistor for each circuit.Compressor Motor Temperature -- On all sizes, this ther-mistor is embedded in the motor windings. There are two ther-mistors in each compressoc One spare is provided.Outdoor Air Temperature -- This sensor is factory-installedto the back of the control box.Remote Space Temperature -- This sensor (part no.33ZCT55SPT) is a field-installed accessory mounted in the in-door space and is used for water temperature reset. The sensorshould be installed as a wall-mounted thermostat would be (inthe conditioned space where it will not be subjected to either acooling or heating source or direct exposure to sunlight, and 4to 5 II above the floor).Space temperatme sensor wires me to be connected toterminals in the unit main control box. See Fig. 28. The spacetemperature sensor includes a terminal block (SEN) and a RJI 1female connector. The RJII connector is used access intothe Carrier Comfort Network® (CCN) at the sensol: SeeFig. 26 and 27.To connect the space temperatme sensor (see Fig. 287:1. Using a 20 AWG twisted pair conductor cable rated forthe application, connect one wire of the twisted pair toone SEN terminal and connect the other wire to the otherSEN terminal located under the cover of the spacetemperatme sensoE2. Connect the other ends of the wires to termin:ds 7 and 8on TB6 located in the unit control box.Units on the CCN can be monitored from the space at thesensor through the RJI 1 connectol: if desired. To wire the RJI 1connector into the CCN:1. Cut the CCN wire and strip ends of the red (+), white(ground), and black (-) conductors. (If another wire colorscheme is used, strip ends of appropriate wires.)52