Operation Data; Capacity Control - Carrier 040-420 Installation And Service Manual

OPERATION
Capacity Control
compressor to give capacity control steps as shown in
Tables 4A-4D. The unit controls leaving chilled water tem-
perature. Entering water temperature is used by the micro-
processor in determining the optimum time to add or sub-
tract steps of capacity, but is not a control set point.
The chilled water temperature set point can be automat-
UNIT CONTROL
STEPS
3 0 G N
,
040 (60 Hz)
045 (60 Hz)
040 (50 Hz)
,
040 (50 Hz)
,
045 (50 Hz)
045 (50 Hz)
050 (60 Hz)
045 (50 Hz)
045 (50 Hz)
045 (50 Hz)
*Unloaded compressor.
**Compressor unloader, accessory.
unloaders, both unloaded.
DATA
Table
4A
LOADING SEQUENCE A
%
Displacement
2 5
1 0 0
1 2 4
4
5
1
4
1
4
5 1 0 0
5 1 0 0
1 8
1
5 6
6
7 1 0 0
1
4
7
ically reset by the return temperature reset or space and out-
door air temperature reset features. It can also be reset from
an external 4-20 mA signal with a loop isolator, or from a
network signal.
The operating sequences shown are some of many pos-
sible loading sequences for the control of the leaving water
temperature. If a circuit has more unloaders than another,
that circuit will always be the lead circuit.
Control Steps, 040-070
Compressors Displacement
A l *
Al :Bl
A l *
Al ,kl
A l "
Al ,k
Al ',Bl
Al ,Bl
A l *
Al
Al *,Bl
Al ,Bl
Al ',Bl
Al ,Bl
Al ,i31
Al +,Bl
Al *,Bl
Al ,Bl
5
LOADING SEQUENCE B
%
Compressors
2 5 Bl*
5 0
A l & *
Al ,'sl*
1 0 0 Al .Bl
5 3
1 0 0
3 8
Al .Bl
6 4
Al ,Bl