Carrier 30GN040-420 operating instructions Head Pressure Control, Pumpout

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Head Pressure Control

EXV UNITS (All 30GN units except 040 and 045 with op- tional brine) Ð The microprocessor controls the condenser fans in order to maintain the lowest condensing temperature possible, thus the highest unit efficiency. Instead of using the conventional head pressure control methods, the fans are con- trolled by the position of the EXV and suction superheat.

As the condensing temperature drops, the EXV opens to maintain the proper suction superheat. Once the EXV is fully open, if the condensing temperature continues to drop, the suction superheat begins to rise. Once the suction superheat is greater than 40 F (22.2 C), a fan stage is removed after 2 minutes.

As the condensing temperature rises, the EXV closes to maintain the proper suction superheat. Once the EXV has closed to 39.5% open (600 steps open), a fan stage is added after 2 minutes.

During start-up, all the condenser fans are started when the condensing temperature reaches 95 F (35 C) to prevent excessive discharge pressure during pulldown. See Table 5 for condenser fan sequence of operation.

For low-ambient operation, the lead fan in each circuit can be equipped with the optional or accessory Motormaster

IIIhead pressure controller. This control has its own sensor which is mounted on a return bend in the liquid portion of the condenser. It will vary the fan speed to maintain a satu- rated condensing temperature of 100 F. The controls auto- matically default to condensing temperature control during this ®rst stage of condenser-fan operation. When subsequent fan stages start, the controls revert to EXV fan control.

TXV UNITS (30GN040,045 with optional brine only) Ð Head pressure control is based on set point control. The micro- processor stages the condenser fans to maintain the set point temperature speci®ed by the controller.

Pumpout

EXV UNITS Ð When the lead compressor in each circuit is started or stopped, that circuit goes through a pumpout cycle to purge the cooler and refrigerant suction lines of refrigerant.

The pumpout cycle starts immediately upon starting the lead compressor and continues until the saturated suction tem- perature is 10° F (5.6° C) below the saturated suction tem- perature at start-up, is 10° F (5.6° C) below the cooler leav- ing ¯uid temperature, or reaches a saturated suction temperature of ±15 F (±26 C). No pumpout is necessary if the saturated suction temperature is below ±15 F (±26 C). At this point, the EXV starts to open and continues to open gradually to provide a controlled start-up to prevent liquid ¯ood-back to the compressor.

At shutdown, the pumpout cycle continues until the satu- rated suction temperature for that circuit is 10° F (5.5° C) below the saturated suction temperature when pumpout is initiated, or saturated suction temperature reaches ±15 F (±26 C). At that point, the compressor shuts down and the EXV continues to move until fully closed.

TXV UNITS Ð Pumpout is based on timed pumpout. On a command for start-up, the lead compressor starts. After 10 seconds, the liquid line solenoid opens. At shutdown, the liquid line solenoid closes, and the lead compressor contin- ues to run for 10 seconds before stopping.

Keypad and Display Module (Also Called HSIO

or LID) Ð The only function of this module is to allow the operator to communicate with the processor. It is used to enter con®gurations and set points and to read data, perform tests, and set schedules. This device consists of a keypad with 6 function keys, 5 operative keys, 12 numeric keys (0 to 9, ·, and -), and an alphanumeric, 8-character LCD. See Fig. 4. See Table 6 for key usage.

IMPORTANT: When entering multiple character in- puts beginning with a zero, a decimal point must be entered in place of the ®rst zero. When entering an in- put of zero, only the decimal point need be entered.

ACCESSING FUNCTIONS AND SUBFUNCTIONS Ð See Tables 6 - 8. Table 7 shows the 6 functions (identi®ed by name) and the subfunctions (identi®ed by number).

AUTOMATIC DEFAULT DISPLAY Ð When keypad has not been used for 10 minutes, display automatically switches to the rotating automatic default display. This display has 7 parts, listed below, which appear in continuous rotating sequence.

DISPLAY

EXPANSION

TUE 15:45

TODAY IS TUE, TIME IS 15:45 (3:45 PM)

LOCAL ON

UNIT IN LOCAL MODE

CLOCK ON

UNIT IS ON VIA CLOCK SCHEDULE

8 MODE

TEMPERATURE RESET IN EFFECT

COOL 1

NUMBER OF STAGES IS 1

2 ALARMS

THERE ARE 2 ALARMS

3 MINS

3 MINUTES REMAINING IN THE OFF-TO-ON

TIME DELAY

 

Fig. 4 Ð Keypad and Display Module

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Contents Controls, Operation, Troubleshooting Unit Sizes and Modular Combinations Unit Model Nominal Section a Section BTons Unit 30GN 30GN Control Panel 040-110 Unit Shown LOCAL/ENABLE-STOP-CCN Switch Positions and Operation LOCAL/ENABLEKeypad and Display Module Also Called Hsio StopCompressor Protection Control Module Cpcs Thermistor and Transducer LocationsThermistors Pressure TransducersÐ Capacity Control Steps Loading Sequence a Loading Sequence B Unit ControlSteps Ð Capacity Control Steps, 040-070 Ð Capacity Control Steps, 040-070 Displacement Compressors Approx 080, 230B 60 Hz A1²,B1²A1²**, B1² A1²**,B1²Compressors Displacement 090, 245B 60 Hz090, 245B 50 Hz 100, 255B 270B 60 HzUnit Control Loading Sequence a Loading Sequence B 270B 50 Hz110, 290B 315B 60 Hz315B 50 Hz A1*,A2,B1 A1,A2,B1 A1²²,A2,B1,B2 A1*,A2,B1,B2 130 60 Hz 130 50 Hz 150, 230A, 245AA1,kB1 170, 270A 330A/B 60 Hz330A/B,360B 50 Hz 330A/B, 360B 50 Hz Approx 190, 290A, 360A/B 390B 60 HzA1,B1 A1**,B1210, 315A, 390A 420A/B 60 Hz420A/B 50 Hz Head Pressure Control PumpoutCondenser Fan Sequence FAN Arrangement FAN Numbers FAN Contactor Controlled byKeypad and Display Module Usage Functions and SubfunctionsFunction USE Keys Operative USE KeysAccessing Functions and Subfunctions Keypad DirectoryTemperature Keypad Directory StatusSubfunction Keypad Entry Display Comment Stage SET PointSubfunction Keypad Entry Display Comment Pressure AnalogInputs OutputsSubfunction Keypad Entry Display Comment Subfunction Keypad Entry Display Comment OutputsSubfunction Keypad Entry Display Comment Compressors Unloaders CPA1Keypad Directory Test Keypad Directory Schedule Keypad Directory Service ConfigurationService Subfunction Keypad Entry Display Comment FactoryALARM/ALERT Subfunction Keypad Entry Display Comment RUN TimeStarts HISTORY²²Reset SET Points Subfunction Keypad Entry Display Comment SET PointsDemand SET Points Date and TimeExample 1 Ð Reading Alarm Codes Example 2 Ð Reading Current Operating ModesKeypad Display Comments Entry Response Operational and Mode Display Codes Example 3 Ð Using Test Function Reset Set PointsExample 5A Ð External Reset Reset AmountsExample 4 Ð Reading and Changing Chilled Fluid Set Point Measurement Method Input Data DescriptionExample 5C Ð Using Return Fluid Temperature Reset Keypad Display Comments Entry ResponsePower SwitchComm Ð Communications Bus PWRService Functions PasswordSUB Keypad Display Comment LoggedonTo Disable Demand Limit Example 8 Ð Setting Time of Day Day of Week4-20 mA Demand Limiting Adjustable Field Congurations Factory Conguration KeystrokesExample 9 Ð Using the Schedule Function Keypad Display Comment EntryProgramming Period Keypad Display Comment Entry Programming PeriodExample 10 Ð Holiday Schedule Function Enter DisplayTypical Stoppage Faults and Reset Types Stop position. Unit cannot start if these contacts areAlarm and Alert Codes LOCAL/ENABLE-STOP-CCNCpcs FSMWSM COM, Comm DGTDsio HPSComm CGF Subfunction. Groups Electronic Expansion Valve EXV EXV Cable Connections to EXV Driver Module, Dsio EXV Thermistor Replacement T1, T2, T7, T8 Temperature Voltage Resistance Drop Ohms Temperature Voltage Resistance Drop Thermistor and Pressure Transducer Locations Thermistor Locations Circuits a and B, Lead Compressor Only Lead Compressor Transducer and Thermistor Locations Module Address Selector Switch Locations Control ModulesAccessory Unloader Installation Installation 4 In/4 Out Module SIOTroubleshooting Standard and Accessory UnloadersPage Or HGBPR-A ²Or HGBPR-BHgbpr Ð COMExternally Powered Outdoor-Air TemperatureCWP Ð Chilled Water Fluid Pump TB Ð Terminal BlockRemote Alarm InterlocksPage Copyright 1995 Carrier Corporation

30GN040-420 specifications

The Carrier 30GN040-420 is a well-regarded model within the industry of chillers, designed to deliver efficient cooling solutions for a variety of commercial applications. Its compact design and advanced technology make it an ideal choice for businesses looking to optimize their HVAC systems.

One of the standout features of the Carrier 30GN series is its flexibility. This chiller model is available in a range of capacities, specifically from 40 to 420 tons, allowing for customized solutions based on specific cooling demands. Such versatility enables this unit to cater to a broad array of installations, from small commercial spaces to larger industrial facilities.

The Carrier 30GN040-420 utilizes a scroll compressor design, known for its reliability and efficiency. The scroll technology allows for a reduction in the number of moving parts, resulting in lower maintenance costs and increased durability. Additionally, the unit operates with environmentally friendly refrigerants such as R-410A, promoting sustainability without compromising performance.

Energy efficiency is another significant aspect of this model. The 30GN series is designed to provide high energy efficiency ratios (EER), which translates to lower operational costs for users over the lifespan of the unit. This is particularly beneficial in an era where energy costs are consistently rising.

The advanced controls found within the Carrier 30GN040-420 further enhance its performance and ease of use. The unit is equipped with a microprocessor-based control system that allows for precise temperature management while providing valuable diagnostic information. This feature not only improves the overall reliability of the system but also facilitates proactive maintenance, reducing the risk of unscheduled downtime.

Moreover, the design of the Carrier 30GN040-420 emphasizes quiet operation, making it suitable for environments where noise levels must be minimized. This characteristic is critical for applications in hospitals, schools, or office buildings, where a peaceful atmosphere is essential.

In summary, the Carrier 30GN040-420 chiller provides a robust solution for businesses requiring dependable and efficient cooling. Its features, including flexible capacity options, reliable scroll compressors, energy-efficient performance, advanced controls, and quiet operation, position it as a top choice for various commercial and industrial applications. As technology continues to evolve, models such as the 30GN series remain at the forefront, meeting the demands of modern HVAC needs while ensuring sustainability and efficiency.
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