Pic Iii System Functions; Capacity Control; Forced - Carrier AquaEdge 23XRV Start-Up, Operation And Maintenance Instructions Manual

To access this display from the ICVC default screen:
1. Press MENU .
2. Press SERVICE .
3. Scroll down to highlight
EQUIPMENT SERVICE
4. Press .
SELECT
5. Scroll down to highlight RAMP_DEM
DESCRIPTION
Pulldown Ramp Type:
Select: Temp=0, KW=1
Demand Limit and kW Ramp
Demand Limit Source
Select: Amps=0, kW=1
Amps or kW Ramp %/Min
Demand Limit Prop Band
Demand Limit At 20 mA
20 mA Demand Limit Opt
VFD Overload Decrease
VFD Overload Delta
Demand Watts Interval
NOTE: No variables are available for CCN read or write operation.
To access this display from the ICVC default screen:
1. Press .
MENU
2. Press SERVICE .
3. Scroll down to highlight EQUIPMENT SERVICE
4. Press SELECT .
5. Scroll down to highlight TEMP_CTL
DESCRIPTION
Control Point Source
ECL Control Option
Temp Pulldown Ramp/Min
Temperature Reset
RESET TYPE 1
Degrees Reset At 20 mA
RESET TYPE 2
Remote Temp –> No Reset
Remote Temp –> Full Reset
Degrees Reset
RESET TYPE 3
CHL Delta T –> No Reset
CHL Delta T –> Full Reset
Degrees Reset
Enable Reset Type

PIC III System Functions

NOTE: Words not part of paragraph headings and printed in all
capital letters can be viewed on the ICVC (e.g., LOCAL,
CCN, RUNNING, ALARM, etc.) Words printed in both all
capital letters and italics can also be viewed on the ICVC and
are parameters (CONTROL MODE ADDED EXAMPLES,
etc.) with associated values (e.g., modes, temperatures, pres-
sures, percentages, on, off, enable, disable, etc.). Words printed
in all capital letters and in a box represent softkeys on the
ICVC (e.g., and
ENTER EXIT
the type of information that can appear on the ICVC screens.
Figures 24-30 give an overview of ICVC operations and
menus. The sequence of screens that should be selected to
view any parameter in the ICVC can be found in Appendix A.
CAPACITY CONTROL — The PIC III control system con-
trols the chiller capacity by changing the compressor speed in
response to chilled liquid temperature deviation away from the
CONTROL POINT. The CONTROL POINT may be changed
by a CCN network device or is calculated by the PIC III
Table 3 — ICVC Display Data (cont)
EXAMPLE 28 — RAMP_DEM DISPLAY SCREEN
.
.
STATUS
0/1
0/1
5 to 20
3 to 15
40 to 100
0/1
25 to 50
3 to 15
5 to 60
EXAMPLE 29 — TEMP_CTL DISPLAY SCREEN
.
.
STATUS
0/1
2 to 10 (1.1 to 5.6)
–30 to 30 (–17 to 17)
–40 to 245 (–40 to 118)
–40 to 245 (–40 to 118)
–30 to 30 (–17 to 17)
0 to 15 (0 to 8)
0-15 (0 to 8)
–30 to 30 (–17 to 17)
0 to 3
). See Table 3 for examples of
UNITS
ramp_opt
dem_src
kw_ramp
% dem_app
% dem_20ma
DSABLE/ENABLE dem_sel
% vfd_dec
% vfd_delt
MIN dw_int
UNITS
DSABLE/ENABLE
^F (^C)
^F (^C)
°F (°C)
°F (°C)
^F (^C)
^F (^C)
^F (^C)
^F (^C)
control adding any active chilled liquid reset to the ECL or LCL
SET POINT. The CONTROL POINT may be viewed or over-
ridden from the MAINSTAT screen. See Fig. 27.
Changes to the chiller capacity and system overrides are
achieved through the VFD SPEED OUTPUT.
The VFD SPEED OUTPUT is controlled by varying the
output from 0 to 100%. The TARGET VFD SPEED is forcible
and allows the operator manual control of the VFD SPEED
OUTPUT. The TARGET VFD SPEED will be allowed to
change every five seconds unless TARGET VFD SPEED is

forced.

The TARGET VFD SPEED is controlled between the VFD
MINIMUM SPEED and VFD MAXIMUM SPEED (refer to
SETUP2 screen) based on the Capacity Control algorithm. The
PIC III controls monitor the compressor oil properties and set a
COMP MINIMUM SPEED to ensure sufficient compressor
bearing lubrication under all operating conditions. The TAR-
GET VFD SPEED shall not be allowed to be forced below the
COMP MINIMUM SPEED. A summary of all capacity control
conditions and responses is shown in Table 4.
45
POINT DEFAULT
1
0
10
10
40
DSABLE
30
5
15
POINT DEFAULT
ecl_opt DSABLE
tmp_ramp 3 (1.7)
deg_20ma 10 (6)
res_rt1 85 (29)
res_rt2 65 (18)
deg_rt 10 (6)
restd_1 10 (6)
restd_2 0 (0)
deg_res 5 (3)
res_sel 0