Marquee Display Usage; Service Test; Configuring And Operating Dual Chiller; Control - Carrier 30GTN Service And Troubleshooting Manual

Marquee Display Usage (See Fig. 18 and
Tables 6-24) —
The Marquee display module provides
the user interface to the ComfortLink™ control system. The
display has up and down arrow keys, an ESCAPE key, and
an ENTER key. These keys are used to navigate through
the different levels of the display structure. See Table 6. Press
the ESCAPE key until the display is blank to move through
the top 11 mode levels indicated by LEDs on the left side of
the display.
Pressing the ESCAPE and ENTER keys simulta-
neously will scroll a clear language text description across
the display indicating the full meaning of each display ac-
ronym. Pressing the ESCAPE and ENTER keys when the
display is blank (Mode LED level) will return the Marquee
display to its default menu of rotating display items. In ad-
dition, the password will be disabled requiring that it be en-
tered again before changes can be made to password protected
items.
Clear language descriptions in English, Spanish, French,
or Portuguese can be displayed when properly configuring
the LANG variable in the Configuration Mode, under DISP
submode. See Table 15.
NOTE: When the LANG variable is changed to 1, 2, or 3,
all appropriate display expansions will immediately change
to the new language. No power-off or control reset is re-
quired when reconfiguring languages.
When a specific item is located, the display will flash show-
ing the operator, the item, followed by the item value and
then followed by the item units (if any). Press the
ENTER key to stop the display at the item value. Items in
the Configuration and Service Test modes are password pro-
tected. The display will flash PASS and WORD when re-
quired. Use the ENTER and arrow keys to enter the 4 dig-
its of the password. The default password is 1111. The password
can only be changed through CCN devices such as
ComfortWorks and Service Tool.
Changing item values or testing outputs is accomplished
in the same manner. Locate and display the desired item.
Press ENTER to stop the display at the item value. Press
the ENTER key again so that the item value flashes. Use
the arrow keys to change the value or state of an item and
press the ENTER key to accept it. Press the ESCAPE key
and the item, value, or units display will resume. Repeat the
process as required for other items.
See Tables 6-24 for further details.
MODE
Run Status

Service Test

Temperature
Pressures
Setpoints
Alarm Status
Inputs
Outputs
ESCAPE
Configuration
Time Clock
Operating Modes
Alarms
Fig. 18 — Scrollling Marquee Display
Service Test (See Table 8) —
control circuit power must be on.
ENTER
Both main power and
The Service Test function should be used to verify proper
operation of compressors, unloaders, hot gas bypass (if in-
stalled), cooler pump and remote alarm relays, EXVs and
condenser fans. To use the Service Test mode, the Enable/
Off/Remote Contact switch must be in the OFF position. Use
the display keys and Table 8 to enter the mode and display
TEST. Press ENTER twice so that OFF flashes, Enter the
password if required. Use either arrow key to change the
TEST value to the On position and press ENTER . Press
ESCAPE and the
sub-mode.
Test the condenser fan, cooler pump, and alarm relays by
changing the item values from OFF to ON. These discrete
outputs are turned off if there is no keypad activity for
10 minutes. Use arrow keys to select desired percentage when
testing expansion valves. When testing compressors, the lead
compressor must be started first. All compressor outputs can
be turned on, but the control will limit the rate by staging
one compressor per minute. Compressor unloaders and hot
gas bypass relays/solenoids (if installed) can be tested with
compressors on or off. The relays under the COMP sub-
mode will stay on for 10 minutes if there is no keypad ac-
tivity. Compressors will stay on until they are turned off by
the operator. The Service Test mode will remain enabled for
as long as there is one or more compressors running. All
safeties are monitored during this test and will turn a com-
pressor, circuit or the machine off if required. Any other mode
or sub-mode can be accessed, viewed, or changed during the
TEST mode. The MODE item (Run/status mode under sub-
mode VIEW) will display ''0'' as long as the Service mode
is enabled. The TEST sub-mode value must be changed back
to OFF before the chiller can be switched to Enable or Re-
mote contact for normal operation.
Configuring and Operating Dual Chiller Con-
trol (See Table 17) —
able for the control of two units supplying chilled fluid on a
common loop. This control is designed for a parallel fluid
flow arrangement only. One chiller must be configured as
the Master, the other chiller as the Slave. The Master chiller
Leaving Fluid Temperature thermistor (T1) must be in-
stalled in the common leaving chilled water line after the
piping has joined from both chillers. See Fig. 19 for ther-
mistor location.
To configure the two chillers for operation, follow the ex-
ample shown in Table 17. The Master chiller will be con-
figured with a slave at address 6. Also in this example, the
Master will be configured to use Lead/Lag Balance to even
out the chiller runtimes weekly. The Lag Start Delay feature
will be set to 10 minutes. The Master and Slave chillers can-
not have the same CCN address (CCNA, Configuration mode
under OPT2). Both chillers must have the control method
variable (CTRL, Configuration mode under OPT2) set to '3.'
In addition, the chillers must both be connected together on
the same CCN bus. Connections can be made to the CCN
screw terminals on TB3 in both chillers. The Master chiller
will determine which chiller will be Lead and which will be
Lag. The Master controls the Slave by forcing the Slave's
CHIL_S_S (CCN) variable, control point (CTPT) and de-
mand limit.
The Master chiller is now configured for dual chiller op-
eration. To configure the Slave chiller, only the LLEN and
MSSL variables need to be set. Enable the Lead/Lag chiller
enable variable (LLEN) as shown Table 17. Similarly, set
the Master/Slave Select variable (MSSL) to SLVE. The vari-
ables LLBL, LLBD, an LLDY are not used by the Slave
chiller.
29
button to enter the OUTS or COMP
The dual chiller routine is avail-