Carrier 69NT20-531-300 manual Perishable Mode -- Economy

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mode and the heaters will be energized . The unit will transition back to the perishable idle mode when the temperature rises to 0.2_C (0.4_F) below the set point and the heaters will de-energize

3.3.7 Perishable Mode -- Economy

The economy mode is an extension of the conventional mode. The mode is activated when the setting of function code Cd34 is “ON”. Economy mode is provided for power saving purposes. Economy mode could be utilized in the transportation of temperature tolerant cargo or non-respiration items which do not require high airflow for removing respiration heat. There is no active display indicator that economy mode has been activated. To check for economy mode, perform a manual display of code Cd34.

In order to achieve economy mode, a perishable set point must be selected prior to activation. When economy mode is active, the evaporator fans will be controlled as follows:

At the start of each cooling or heating cycle, the evaporator fans will be run in high speed for three minutes. They will then be switched to low speed any time the supply air temperature is within ¦ 0.25_C (0.45_F) of the set point and the return air temperature is less than or equal to the supply air temperature + 3_C (5.4_F). The fans will continue to run in low speed for one hour. At the end of the hour, the evaporator fans will switch back to high speed and the cycle will be repeated. If bulb mode is active, the economy fan activity will be overwritten.

3.3.8 Perishable Mode -- Dehumidification

The dehumidification mode is provided to reduce the humidity levels inside the container. The mode is activated when a humidity value is set at at function code Cd33. The display module SUPPLY led will flash ON and OFF every second to indicate that the dehumidification mode is active. Once the Mode is active and the following conditions are satisfied, the controller will activate the heat relay to begin dehumidification.

1.The humidity sensor reading is above the set point.

2.The unit is in the perishable steady state mode and supply air temperature is less than 0.25_C above set point.

3.The heater debounce timer (three minutes) has timed out.

4.Heater termination thermostat (HTT) is closed.

If the above conditions are true the evaporator fans will switch from high to low speed operation. The evaporator fan speed will switch every hour thereafter as long as all conditions are met (see Bulb Mode section for different evaporator fan speed options). If any condition except for item (1) becomes false OR if the relative humidity sensed is 2% below the dehumidification set point, the high speed evaporator fans will be energized.

In the dehumidification mode power is applied to the defrost and drain pan heaters. This added heat load

causes the controller to open the suction modulating valve to match the increased heat load while still holding the supply air temperature very close to the set point.

Opening the modulating valve reduces the temperature of the evaporator coil surface, which increases the rate at which water is condensed from the passing air. Removing water from the air reduces the relative humidity. When the relative humidity sensed is 2% below the set point , the controller de-energizes the heat relay. The controller will continue to cycle heating to maintain relative humidity below the selected set point. If the mode is terminated by a condition other than the humidity sensor, e.g., an out-of-range or compressor shutdown condition, the heat relay is de-energized immediately.

Two timers are activated in the dehumidification mode to prevent rapid cycling and consequent contactor wear. They are:

1.Heater debounce timer (three minutes).

2.Out-of-range timer (five minutes).

The heater debounce timer is started whenever the heater contactor status is changed. The heat contactor remains energized (or de-energized) for at least three minutes even if the set point criteria are satisfied.

The out-of-range timer is started to maintain heater operation during a temporary out-of-range condition. If the supply air temperature remains outside of the user selected in-range setting for more than five minutes, the heaters will be de-energized to allow the system to recover. The out-of-range timer starts as soon as the temperature exceeds the in-range tolerance value set by function code Cd30.

3.3.9 Perishable, Dehumidification -- Bulb Mode

Bulb mode is an extension of the dehumidification mode which allows changes to the evaporator fan speed and/or defrost termination set points.

Bulb mode is active when configuration code Cd35 is set to “Bulb”. Once the bulb mode is activated, the user may then change the dehumidification mode evaporator fan operation from the default (speed alternates from low to high each hour) to constant low or constant high speed. This is done by toggling function code Cd36 from its default of “alt” to “Lo” or “Hi” as desired. If low speed evaporator fan operation is selected, this gives the user the additional capability of selecting dehumidification set points from 60 to 95% (instead of the normal 65 to 95%).

In addition, if bulb mode is active, function code Cd37 may be set to override the previous defrost termination thermostat settings. (Refer to paragraph 4.9.5.) The temperature at which the defrost termination thermostat will be considered “open” may be changed [in 0.1_C (0.2_F) increments] to any value between 25.6_C (78_F) and 4_C (39.2_F) . The temperature at which the defrost termination thermostat is considered closed for interval timer start or demand defrost is 10_C for “open” values from 25.6_C (78_F) down to a 10_C setting. For “open” values lower than 10_C, the “closed” values will decrease to the same value as the “open” setting. Bulb mode is terminated when:

3-5

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Contents Service Model Safety Summary 309 Safety-2 Safety-3 309 Table of Contents Table of Contents Connect Remote Monitoring Check Controller Function CodesReplacing The Evaporator Fan Assembly Valve ReplacementEvaporator Coil Replacement Evaporator Heater Replacement Precheck Procedure Checking The Stepper valveElectrical Wiring Schematic Refrigeration Circuit Schematic Standard Operation Refrigeration Circuit Schematic Economized OperationDataCORDER Configuration Variables List of TablesSection Introduction Unit is fitted with a scroll compressorManual, T-300 Section Description Evaporator Section Compressor Section Condenser Section Module which allow communication with a master Communications interface module For further informationApproved Oil Mobil ST32 Oil Charge 2957 ml 100 ounces Model RSH105 Weight Dry 46.5 kg 103 lbTemperature 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 Temperature Control System Section MicroprocessorKEY Function Controller Software Modes of Operation Perishable Mode -- Economy Controller Alarms Unit PRE-TRIP Diagnostics DCF02=5 Usda thermistor inputs Thermistor inputssupply & returnDCF02=2 DCF02=6Standard Configuration Download Report Raw Data Report for ABC1234567DataCORDER may be powered up in any one of four ways Logging Interval dCF03DataView DataCORDER Alarms CnF33 Snap Freeze Option CnF11 Defrost Off Selection NoOFFStd, Full SnAPDisplay Only Functions Sensor Reading Defrost temperature sensor reading is displayedPossibly delaying a needed defrost cycle Plicable with frozen set pointsController Function Codes Sheet 3 Controller Alarm Indications Sheet 1 Controller Alarm Indications Sheet 2 Controller Alarm Indications Sheet 3 Error Description Memory failureDraw test is done after 10 seconds Draw test is done after 15 secondsP1-1 OndsP6-2 Supply is comparedTest fails Crease, the test failsDenser fan is started and a 60 second timer is started Pressure switch is open or the condenser fan switch is openTimer is started Requirements Control temperature must be at least 15.6C 60FRequirements Control temperature must be at least 7.2C 45F Set point, the test proceeds to testBy starting P10-0 over Inapplicable Functions Display Title Data 10 DataCORDER Alarm Indications Operation 69NT Fresh AIR MakeupWill be displayed To start a pre-trip test, do the followingWill be displayed Controller Operation -- Perishable Mode Pull Down Falling RisingController Operation -- Frozen Mode Frozen Mode Defrost Section Troubleshooting Unit will not heat or has insuffi Will not initiate defrost Bent motor shaftSuperheat Unit reads abnormal currents Current sensor wiring Check Section Service Valve Frontseated BackseatedCompressor 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 Two expansion valves are used, the evaporator Wrapped with Insulating compound. SeeRemoving the Expansion Valve Equalizer line Cleaned regularly. The preferred cleaning fluid is freshIf applicable, braze the equalizer connection to Check superheat refer to stepStart unit and check operation 14. Unloader Solenoid ValveEvaporator FAN Motor Capacitors Valve Override Controls Precheck Procedure TP1 Mounting Stud Type Shorter than the other wire Cut wires 5 cm 2 inches from shoulder of defecCut one wire of existing cable 40 mm 1-1/2 inch Cut one replacement sensor wire opposite colorMaintenance of Painted Surfaces 23 Door Hinge Repair Crack, Chip & Hole Repair Kit 24. Insert Location In-lbs #10 Ft-lbs 12.72 17.14 In-lbs Ft-lbs 13.99 18.8614.6 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.

One of the standout features of the Carrier 69NT20-531-300 is its high energy efficiency. It is equipped with advanced compressor technology that optimizes performance while reducing energy consumption. This ensures that businesses can maintain a comfortable indoor climate without incurring exorbitant utility bills. With a high Seasonal Energy Efficiency Ratio (SEER) and Energy Efficiency Ratio (EER), users can expect not only enhanced comfort but also significant cost savings over time.

The cooling capabilities of the 69NT20-531-300 are complemented by its robust heating options. This unit utilizes a gas heat exchanger, ensuring quick and even heating throughout the space. The combination of cooling and heating capabilities in one compact unit makes it a versatile choice for various applications, including retail spaces, offices, and warehouses.

In addition to its impressive performance specifications, the Carrier 69NT20-531-300 incorporates innovative technologies that further enhance its functionality. The unit comes with advanced controls, allowing for precise temperature regulation and zoning capabilities. This ensures that different areas of a building can maintain their desired temperatures based on usage, improving overall energy efficiency.

Durability is another hallmark of the Carrier 69NT20-531-300. The unit is constructed with high-quality materials and features a weather-proof cabinet that protects it from the elements, ensuring long-term reliability even in harsh conditions. Furthermore, its modular design simplifies maintenance, making it easy for technicians to access critical components.

The 69NT20-531-300 is also designed with low noise operation in mind. It employs sound-dampening technology to ensure that operations are quiet, making it an ideal choice for locations where noise reduction is a priority, such as schools or healthcare facilities.

Overall, the Carrier 69NT20-531-300 stands out as a premier choice for businesses looking for an efficient, reliable, and feature-rich rooftop HVAC unit. Its blend of energy efficiency, advanced technology, and durability positions it as a leader in commercial heating and cooling solutions, making it a valuable investment for any commercial property.
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