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19. Load Shedding Options
The M3 unit controller may be setup to de-energize part or all of the mechanical cooling provided by a rooftop unit.
Configuration ID 2
, position
8
defines where the digital input for load shedding is configured.
Go to
SETUP > INSTALL > Configuration ID 2
, position 8 will need to be set to one of the following options:
N - NOT INSTALLED
G - GLOBAL INPUT (A55-P297-9)
2 - DI-2 (DIGITAL INPUT 2 - A55 - P299 - 4)
3 - DI-3 (DIGITIAL INPUT 3 - A55 - P299 - 6)
NOTE
: When
options
2
or
3
are enabled on either DI-2 or DI-3, these inputs cannot not be shared with any other devices
(i.e, global, blower overload or drain pan overflow). Similarly option G (Global input) may be used only if economizer
global mode is not enabled.
Parameter 194 - select 0 - 4. This parameter defines how many compressors are turned off when load shedding is active
(i.e., digital input ON; contact closed).
Table 51. M3 Load Shedding Options
Control Parameter
Control Value
Units
Description
No
Screen Name
Parameter
Short
Description
Min.
Default
Max
.
194
LOAD SHED NUM COMP
Number of com
pressors to
shed during
load shedding
0
0
4
Option
Number of compressors to be
turned off when load shedding is
active.
For 2-stage A box compressor, a
value of one shuts off 2nd stage
only and a value of 2 turns com
pressor completely off.
