Space Temperature Reset; Demand Limit; Switch Controlled Demand Limit - Carrier AQUAFORCE 30XA080-500 Controls, Start-Up, Operation, Service And Troubleshooting Instructions

7
6
5
4
Cooling Reset
Deg. Value,
3
DGRC
2
1
0
60
To configure this option with the Touch Pilot™ display:
DISPLAY NAME PATH
Cooling Reset Main Menu
 
Select Config
Current No Main Menu
 
Reset Value Setpoint
Current Full Main Menu
 
Reset Value Setpoint
Cooling Reset Main Menu
 
Deg. Value Setpoint
To configure this option with the Navigator™ display:
ITEM ITEM EXPANSION
Cooling Reset
CRST Configuration
Type
Current No
CRV1 Setpoints
Reset Temp
Current Full
CRV2 Setpoints
Reset Temp
DGRC Degrees Cool
Setpoints
Reset
In the example in Fig. 27, at 4 mA no reset takes place and
at 20 mA, 5° F (2.8° C) chilled water set point reset is required.
Demand limit is a feature that allows
Demand Limit —
the unit capacity to be limited during periods of peak energy
usage. This allows the owner to keep energy costs down. There
are three types of demand limiting that can be configured. The
first type is through 2-step switch control, which will reduce
the maximum capacity to 2 user configurable percentages. The
second type is by 4 to 20 mA signal input which will reduce the
Space T Full Reset Value,
CRS2
65
Space Temperature (deg F)
Fig. 26 — Space Temperature Reset
LINE
VALUE
NO.
Default =0
(No Reset)
19
USER 3 (4-20mA
Control)
4.0 mA
9
SETPOINT Default = 0.0
30.0 mA
10
SETPOINT Default = 0.0
Default =
13
SETPOINT 0.0 F (0.0 C)
PATH VALUE
Default =

RSET No Reset
4-20mA Input

4.0 mA
COOL
Default = 0.0
 20.0 mA
COOL
Default = 0.0
 5.0 F (2.8 C)
COOL
Default = 0.0
Space T No Reset Value,
70
maximum capacity linearly between 100% at a 4 mA input
signal (no reduction) down to the user-configurable level at a
20 mA input signal. The third type uses the CCN Loadshed
module and has the ability to limit the current operating capaci-
ty to maximum and further reduce the capacity if required. De-
mand limit control can be based on a calculated capacity level
or by compressor current level.
NOTE: If using the compressor current level for demand limit,
take into account the other power draws such as the condenser-
fan motors when determining the limit value desired.
SWITCH CONTROLLED DEMAND LIMIT — The con-
trol system is capable of demand limit based on a field-sup-
plied switch for 1-step demand limit or 2 switches for 2-step
demand limit. One-step Demand Limit is standard. The 2-step
switch control of demand limiting requires the Energy Man-
agement Module (EMM). Demand Limit steps are controlled
by two relay switch inputs field wired to TB5-5 and TB5-14
for Switch 1 and TB6-14 and TB6-15 for Switch 2.
For demand limit by switch control, closing the first de-
mand limit contact will put the unit on the first demand limit
level, either by capacity or compressor current. The unit will
not exceed the percentage of capacity or compressor current
entered as Demand Limit Switch 1 set point. Closing contacts
on the second demand limit switch prevents the unit from ex-
ceeding the demand limit entered as Demand Limit Switch 2
set point. The demand limit percent capacity or compressor
current that is set to the lowest demand takes priority if both de-
mand limit inputs are closed. If the demand limit percentage
does not match unit operation, the unit will limit capacity or
current to the closest step without exceeding the value.
To use Demand Limit, select the type of demand limiting to
use by configuring the Demand Limit Select variable (De-
mand Limit Type Select, DMDC) to Switch. Configure the
Demand Limit set points based on the type selected.
42
CRS1
75 80
a30-4481