Carrier HS070-160 Troubleshooting Manual

Also see for 30HR070: Installation, Start-Up and Service Instructions Installation, Start-Up and Service Instructions

Contents

TROUBLESHOOTINGIf necessary, review the Flotronic Plus Control System,Control Sequence, and Controls Operation sectionsfound in this book. Tables 5 and 6 show how to use thekeyboard/display module to access functions and sub-functions. (These procedures are also explained in the3OHR,HS Installation, Start-Upand Service Instructionsalong with examples and details on using the controlfeatures. A copy of the installation instructions should bekept handy while troubleshooting.)Checking Display Codes - To determine how themachine has been programmed to operate, check thediagnostic information ( and operatingmode displays ( If no display appears,follow the procedures in Troubleshooting, Modules,page 23. If the display is working, continue as follows:1. Note all the alarm codes displayed (2. Note all the operating mode codes displayed(ppq).3. Note the leaving chilled water temperature set pointin effect and the current leaving water temperatureIf the machine is running, compare the “in effect”leaving water temperature set point with the currentwater temperature. Remember that if reset is in effect,they may be different because the machine is operatingto the modified chilled water set point. If the currenttemperature is equal to the set point but the set pointis not the one desired, recall that if dual set point hasbeen selected in the schedule function, there are 2 setpoints to which the machine can be operating. Checkthe programming of the schedule function to see if theoccupied or unoccupied set point should be in effect.OPERATING MODE CODES - Following is anexplanation of the operating mode codes:Temperature Reset (21) ~ In this mode, the unit is usingtemperature reset to adjust the set point, and the unit iscontrolling to the modified set point. This means that theleaving water temperature may not equal the chilled waterset point. The set point can be modified based on returnwater, outside air temperature or space temperature.Demand Limit (22) - This indicates that the capacity ofthe unit is being limited by the demand limit controloption. The unit may not be able to produce the desiredleaving water temperature because the unit may not loadto full capacity.Pulldown Control (24) -- If this option is in effect andthe cooler water temperature is warm, extra stages willnot be added if the water temperature leaving the cooler isdecreasing faster than I0 F (0.6 C) per minute.Standby (26) ~ The unit is being held in the standbymode either because the RUN /STANDBY switch is onenor a set of relay contacts in series with the KUN/STANDBY switch is open (contacts wired betweenterminals TBl-13 and TBI-14).Unoccupied Mode (27) - In dual set point schedule, thismode means the machine is operating to the unoccupiedset point. In single set point schedule, this mode shutsdown the unit in the same manner as “Unit Standby.”If the schedule is holding the machine off when it isneeded, set the schedule for inactive mode until theschedule can be properly reprogrammed. (See the Sched-ule Function section of the Installation, Start-Up andService Instructions.) The override feature can also -beused to temporarily place the unit in occupied mode.Enter c lSCHD , then the number of hours to override(1 to 4), then press EWR .0 If the unit is in override andyou wish to cancel it, enter zero hours in the same manner.Run Mode (28)To enter the MODES subfunction, depress p-j Fjand use the 4 key to determine if more than onemode applies.Do not attempt to bypass, short or modify thecontrol circuit or electronic boards in any way tocorrect a problem. This could result in componentfailures or a hazardous operating condition.ALARM CODES - The following is a detailed descrip-tion of each alarm code error and the possible cause.Manual reset of an alarm is accomplished by moving theRUN/STANDBY switch to STANDBY, then backto RUN.Codes 5 l-54, Compressor Failure - If the DSIO relaymodule relay or control relay feedback switch opensduring operation of a compressor, the microprocessorwill detect this and will stop the compressor, energizethe alarm light, and display a code of 5 1 to 54, dependingon the compressor. The compressor will be locked off;to reset, use the manual reset method.If the lead compressor in a circuit is shut down, all theother compressors in the circuit will be stopped andlocked off. Only the alarm code for the lead compressorwill be displayed,The microprocessor has also been programmed toindicate a compressor failure if the feedback terminal onthe 253 terminal strip receives voltage when the com-pressor is not supposed to be on.Following are possible causes for this failure:High-Pressure Switch Open - The high-pressure switchfor each compressor is wired in series with the 24-voltpower that energizes the compressor control relay. If thehigh-pressure switch opens during operation the com-pressor will stop and this will be detected by the micro-processor through the feedback terminals.Discharge Gas Thermostat ~ The discharge gas thermo-stat switch in each compressor is also wired in series withthe 24-volt power that energizes the control relay (CR).If the switch opens during operation of the compressor,the compressor will be stopped and the failure will bedetected through the feedback terminals.DSIO Module Failure ~ If a DSIO relay module relayfails open or closed, the microprocessor will detect thisand lock the compressor off and indicate an error.Wiring Errors - If a wiring error exists causing the CRor feedback switch not to function properly, the micro-nrocessor will indicate an error. : I1Processor (PSIO) Failure - If the hardware thatmonitors the feedback switch fails or the processor failsto energize the relay module relay to ON, an error maybe indicated.t.,12