Fig. 8 Ð 4-20 mA Cooling Temperature Reset

Example 6 Ð Changing Reset Type

To change type of reset, ®rst log on as shown in Table 12. Also refer to Set Point Function section, page 38, for information on entering reset set points using reset feature.

KEYPAD

DISPLAY

COMMENTS

ENTRY

RESPONSE

 

 

 

 

 

 

Field con®guration

 

FLD CFG

subfunction of

 

 

service function

 

CSPTYP 0

Scroll past single cooling

 

set point

 

 

 

CRTYP 0

No reset has been

 

selected

 

 

 

CRTYP 1

Internally powered 4-20 mA

 

signal reset is selected

 

 

 

 

Space or outdoor-air

 

CRTYP 2

temperature reset is

 

 

selected

 

CRTYP 3

Return ¯uid temperature

 

reset is selected

 

 

 

CRTYP 4

Externally powered 4-20 mA

 

signal reset is selected

 

 

 

CRTYP 0

Reset is deactivated

 

 

 

To use Demand Limit, ®rst enable loadshed, then enter demand limit set points. See Example 7A. Closing the ®rst stage demand limit contact puts unit on the ®rst demand limit level, that is, the unit does not exceed the percentage of ca- pacity entered as demand limit stage 1. Closing contacts on second-stage demand limit relay prevents unit from exceed- ing capacity entered as demand limit stage 2. The demand limit stage that is set to the lowest demand takes priority if both demand limit inputs are closed.

The demand limit function must be enabled in order to function and may be turned off when its operation is not de- sired. The demand limit relays can, in off condition, remain connected without affecting machine operation.

Table 12 Ð Service Functions

To view and modify con®gurations, the password must be entered under the log on subfunction.

SUB-

KEYPAD

DISPLAY

COMMENT

FUNCTION

ENTRY

 

 

 

 

 

 

1 Log On

 

PASSWORD

Enter Password/

 

 

 

Disable Password

 

 

LOGGEDON

Logged On

 

 

 

 

NOTE: Con®gurations may be modi®ed at this time. When ®nished viewing and/or modifying con®gurations, log out as follows:

 

 

LOGGEDON

Ð

 

 

LOG OFF

Disable Password

 

 

Protection

 

 

 

 

 

 

Logged Off/

 

 

EXIT LOG

Enable Password

 

 

 

Protection

 

 

 

 

2 Version

 

VERSION

Software

 

 

Information

 

 

 

 

 

XXXXXXXX

Version No.

 

 

of Software

 

 

 

 

 

 

 

Demand Limit, 4 to 20 mA Signal Ð The controls can also accept a 4 to 20 mA signal for load shedding. Input for the signal are terminals shown below:

Externally powered

Positive lead to J7-5 - 4 In/4 Out Module

Negative lead to J7-6 - 4 In/4 Out Module

Internally powered

Positive lead to J7-6 - 4 In/4 Out Module Negative lead to J7-7 - 4 In/4 Out Module

See Field Wiring section on page 69 and Fig. 7.

42

Page 41 Page 43
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Image 42
Carrier 30GN040-420 operating instructions Service Functions, SUB Keypad Display Comment, Password, Loggedon
Page 41 Page 43

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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