Carrier 69NT20-531-300 manual Valve Override Controls

Page 77

under load conditions. The important advantages of a analyzer are its ability to locate capacitors that have failed to hold their microfarad ratings, or those that are breaking down internally during operation. It is also useful in identifying capacitors when their microfarad rating marks have become unreadable.

6.19 VALVE OVERRIDE CONTROLS

CAUTION

DO NOT disassemble piston from NEW suc- tion modulating valve powerhead assembly. Doing so may result in damage to piston.

Controller function code Cd41 is a configurable code that allows timed operation of the automatic valves for troubleshooting. Three test sequences are provided. The first, capacity mode (CAP), allows alignment of the unloader and economizer solenoid valves in the standard, unloaded and economized operating configurations. The second, SMV % Setting (SM) allows opening of the suction modulating valve to various percentages and the third, Oil Valve Setting (OIL) and Liquid Valve Setting (LIV) allows opening or closing of the oil return solenoid valve and the liquid injection solenoid valve. A fourth selection is also provided to enter a time period of up to three minutes, during which the override(s) are active. If the timer is active, valve override selections will take place immediately. If the timer is not active, changes will not take place for a few seconds after the timer is started. When the timer times out, override function is automatically terminated and the valves return to normal machinery control. To operate the override, do the following:

a.Press the CODE SELECT key then press an ARROW key until Cd41 is displayed in the left window. The right window will display a controller communica- tions code.

b.Press the ENTER key. The left display will show a test name alternating with the test setting or time re- maining. Use an ARROW key to scroll to the desired test. Press the ENTER key and SELCt will appear in the left display.

c.Use an ARROW key to scroll to the desired setting, and then press the ENTER key. Selections available for each of the tests are provided in the following table.

d.If the timer is not operating, follow the above proce- dure to display the timer. Use an ARROW key to scroll to the desired time interval and press ENTER to start the timer.

e.The above described sequence may be repeated dur- ing the timer cycle to change to another override.

Right Display

Available Selections

CAP

AUtO

(Capacity Mode)

(Normal Control)

 

UnLd

 

(Unloader = Open

 

Economizer = Closed)

 

Std

 

(Unloader = closed

 

Economizer = closed)

 

ECOn

 

(Unloader = closed

 

Economizer = open)

SM

AUtO

(SMV % Setting)

(Normal Control)

 

0

 

3

 

4

 

6

 

12

 

25

 

50

 

100

OIL

AUto

(Oil Valve Setting)

(Normal Control)

 

CLOSE

 

OPEn

LIV

AUto

(Liquid Valve Setting, if

(Normal Control)

applicable)

CLOSE

 

OPEn

tIM

0 00 (0 minutes/0 Seconds)

(Timer)

In 30 second increments to

 

3 00 (3 minutes/ 0 seconds)

6.20 SUCTION MODULATION VALVE

On start up of the unit, the valve will reset to a known open position. This is accomplished by assuming the valve was fully open, driving it fully closed, resetting the percentage open to zero, then opening to a known 10% staging position.

FROM COIL

2-1/8 inch Nut

 

TO COMPRESSOR

FROM UNLOADER

Figure 6-17 Suction Modulation Valve (SMV)

6-13

T-309

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Contents Service Model Safety Summary 309 Safety-2 Safety-3 309 Table of Contents Table of Contents Check Controller Function Codes Connect Remote MonitoringEvaporator Coil Replacement Evaporator Heater Replacement Valve ReplacementReplacing The Evaporator Fan Assembly Precheck Procedure Checking The Stepper valveElectrical Wiring Schematic Refrigeration Circuit Schematic Economized Operation Refrigeration Circuit Schematic Standard OperationList of Tables DataCORDER Configuration VariablesUnit is fitted with a scroll compressor Section IntroductionManual, T-300 Section Description Evaporator Section Compressor Section Condenser Section Communications interface module For further information Module which allow communication with a masterTemperature Model RSH105 Weight Dry 46.5 kg 103 lbApproved Oil Mobil ST32 Oil Charge 2957 ml 100 ounces Oil level range, with the compressor offElectrical Data Safety and Protective Devices Refrigeration Circuit 2.5.1 Standard Operation Standard Operation with Receiver Refrigeration Circuit Schematic -- Economized Operation Section Microprocessor Temperature Control SystemKEY Function Controller Software Modes of Operation Perishable Mode -- Economy Controller Alarms Unit PRE-TRIP Diagnostics DCF02=2 Thermistor inputssupply & returnDCF02=5 Usda thermistor inputs DCF02=6Raw Data Report for ABC1234567 Standard Configuration Download ReportLogging Interval dCF03 DataCORDER may be powered up in any one of four waysDataView DataCORDER Alarms Std, Full CnF11 Defrost Off Selection NoOFFCnF33 Snap Freeze Option SnAPDisplay Only Functions Possibly delaying a needed defrost cycle Defrost temperature sensor reading is displayedSensor Reading Plicable with frozen set pointsController Function Codes Sheet 3 Controller Alarm Indications Sheet 1 Controller Alarm Indications Sheet 2 Controller Alarm Indications Sheet 3 Memory failure Error DescriptionP1-1 Draw test is done after 15 secondsDraw test is done after 10 seconds OndsTest fails Supply is comparedP6-2 Crease, the test failsTimer is started Pressure switch is open or the condenser fan switch is openDenser fan is started and a 60 second timer is started Requirements Control temperature must be at least 15.6C 60FBy starting P10-0 over Requirements Control temperature must be at least 7.2C 45FSet point, the test proceeds to test Inapplicable Functions Display Title Data 10 DataCORDER Alarm Indications 69NT Fresh AIR Makeup OperationTo start a pre-trip test, do the following Will be displayedWill be displayed Pull Down Falling Rising Controller Operation -- Perishable ModeController Operation -- Frozen Mode Frozen Mode Defrost Section Troubleshooting Unit will not heat or has insuffi Bent motor shaft Will not initiate defrostSuperheat Unit reads abnormal currents Current sensor wiring Check Valve Frontseated Backseated Section ServiceCompressor in a deep vacuum, internal dam- age will result Refrigerant Leak Checking Remove all refrigerant using a refrigerant recovery system Refrigerant Charge Compressor Upper Mounting Compressor OIL Level Condenser FAN and Motor Assembly Removing the Expansion Valve Two expansion valves are used, the evaporatorWrapped with Insulating compound. See If applicable, braze the equalizer connection to Cleaned regularly. The preferred cleaning fluid is freshEqualizer line Check superheat refer to step14. Unloader Solenoid Valve Start unit and check operationEvaporator FAN Motor Capacitors Valve Override Controls Precheck Procedure TP1 Mounting Stud Type Cut one wire of existing cable 40 mm 1-1/2 inch Cut wires 5 cm 2 inches from shoulder of defecShorter than the other wire Cut one replacement sensor wire opposite colorMaintenance of Painted Surfaces 23 Door Hinge Repair Crack, Chip & Hole Repair Kit 24. Insert Location In-lbs Ft-lbs 13.99 18.86 In-lbs #10 Ft-lbs 12.72 17.1414.6 49.4 37.08 12.3 41.6 31.25 32.8 24.64 22.7 17.00 11.9 Section Electrical Wiring Schematic Schematic Diagram Wiring Diagram Sheet 1 Wiring Diagram Sheet 2 Index 309 Index-2

69NT20-531-300 specifications

The Carrier 69NT20-531-300 is a cutting-edge rooftop unit designed to meet the demanding requirements of commercial heating and cooling applications. This model embodies Carrier’s commitment to energy efficiency, reliability, and advanced technological features that enhance indoor comfort while minimizing operational costs.

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