Carrier 040-420 Installation And Service Manual

Example 2 - Reading Current Operating ModesKEYPADIDISPLAYENTRY RESPONSE I COMMENTSTUE 15:45 Keypad has not been used for atLOCAL ON least 10 minutes Rotating summaryC O O L 1 display appears on screen0 A L A R M Sp-lH 2 MODES There are 2 modes currently in effectc l4 LOCAL ON Unit is on by chiller on/off switchc l+ M O D E 8 Temperature reset is in effectl-ii 1;;;;1 (Stage) - This subfunction displays the capac-ity stage number. See Tables 4A-4D for compressor load-ing sequence. To enter the STAGE subfunction, pressp--&q and use the q to display the stage number.Additional m provides the following information:Percent of total unit capacity being utilized.Percent of each circuit capacity being utilized.Demand limit set point in effect (can be any value be-tween 0% and 100%).Load limit set point in effect. This is a CCN function forcontrolling operation of multiple units between 0% and100% of total capacity of all units combined.Status of each compressor relay. When a compressor ison, the number of that compressor is displayed. If a com-pressor is off, a 0 is displayed. For example: In a givencircuit, if compressors 1 and 3 are running, and 2 and 4are not running, 0301 is displayed for that circuit.Load/Unload factor for compressors. This factor is an in-dication of when a step of capacity is added or sub-tracted. Its value can range from slightly less than -1 .Oto slightly more than + 1 .O. When load/unload factorreaches + 1.0, a compressor is added. When the load/unload factor reaches -1 .O, a compressor is subtracted.If compressor unloaders are used, at -.6 a compressor isunloaded and at + .6, a compressor is loaded up.mF[ (Set Point) - This subfunction displays leavingwater temperature and leaving chilled water set point. Ifunit is programmed for dual set point, the chilled water setpoint currently in effect (either occupied or unoccupied) isdisplayed. If reset is in effect, the unit operates to the mod-ified chilled water set point. This means the leaving watertemperature may not equal the chilled water set point Themodified chilled water set point can also be displayed in theStatus function. To enter the set point subfunction, de-press mb[ and use the q to display modified leavingchilled water set point followed by leaving water set pointand actual cooler leaving fluid temperature.F[ F[(Temperature) - The temperature subfunction dis-plays the readings at temperature sensing thermistors.To read a temperature, enter Fi Fi , then scroll to de-sired temperature using the m key. See Table 9 for theorder of readouts.flH (Pressure) - This subfunction displays suction,discharge and net oil pressure at lead compressor of eachcircuit of unit.m H (Analog Inputs) - This subfunction displaysanalog inputs, if any. Enter m Fi , then use the q . Thetransducer supply voltage, 4-20 mA reset signal can be dis-played. This is useful for problem diagnosis prior to usingthe test function.m bi( I n p u t s ) - This subfunction displays status(ON/OFF) of input switch where applicable. Status of dualset point switch, and demand limit switches 1 and 2 can bedisplayed. This is useful for problem diagnosis prior to us-ing the test function.~~ (Outputs) - This function displays ON/OFF sta-tus of alarm relay, all fan relays, and chilled water pumprelay. It also displays ON/OFF status of compressor unload-ers (if used). The position of each EXV (in percent open)can be displayed.TEST FUNCTION - The test function operates the diag-nostic program. To initiate test function, the LOCAL/ENABLE-STOP-CCN switch must be in STOP position.To reach a particular test, enter its subfunction number,then scroll to desired test by pressing the ( key. PressB to start a test. Press q or q or H to terminate orexit a test. Pressing the q key after a test has started ad-vances system to next test, whether current test is operatingor has timed out, Once in the next step, you may starttest by pressing H or advance past it by pressing I)I .While the unit is in test, you may leave test function andaccess another display or function by pressing appropriatekeys. However, a component that is operating when an-other function is accessed remains operating. You mustre-enter test function and press the ) key to shut downthe component. Components with a timed operating limittime out normally even if another function is accessed.Keypad entry riF[ allows the operator to make thefollowing checks by using m :LID display check. Propezisplay is 8.8.8.8.8.8.8.8 .Operation of remote alarm.Operation of condenser fans.Operation of chilled water pump.Operation of EXVs. To drive EXV fully open, enterm m m (100% open). To drive EXV fully closed, en-ter u (0% open). cKeypad entry -mH Ia c c e s s e s the compressor and.compressor unloader operational tests.During compressor operational tests, compressor startsand runs for 10 seconds. Compressor service valves mustbe open. Energize crankcase heaters 24 hours prior toperforming compressor tests.Since test function checks only certain outputs, it is goodpractice to also check all inputs and outputs accessiblethrough the status function. These are located at F\ F[ ,m H, and mm (see Table 9). If keypad is not usedfor 10 minutes, unit automatically leaves test function andresumes rotating display. See Example 3.38