AERCO Control System (ACS)
CHAPTER 3
: Operation
Page 60 of 139
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, New York 10913
11/22/2017
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Phone: 800-526-0288
OMM-0081_0F
3.11.8 SETPT DOWN RATE (Setpoint Down (descending) Rate
If we go back above the HI_DB_SETPT_EN value, after first going below it and adjusting to
'Se DEADBAND HIGH', this defines the rate at which to decrease 'Se
DEADBAND HIGH' back down to Setpoint. The default is set to 100° per minute.
3.11.9 DEMAND OFFSET
This setting defines an offset to the Active Setpoint such that when the ACS shuts down the
whole boiler plant, it will not allow any boiler to fire again until both the Header Temperature <
Active Setpoint - DEMAND OFFSET, and the Percent Level Output >= the BLR START LEVEL.
During the time that the output is being kept at 0%, the ACS will flash the second line of its
default display. The default value here is 10°F.
NOTE
In the Revision C firmware and later, the BMSII will shut down the
last boiler firing when the Percent Output Level goes below the
BLR STOP LEVEL. The shutdown will be indicated by the second
line of the default display flashing. By the same token, as the
Percent Level Output rises from 0%, the second line of the default
(Operating Menu) display will flash until it reaches the BLR
START PERCENT and the Header temperature is below 'Setpoint
- DEMAND OFFSET'.
RELAY MENU
3.11
As the name implies, the
RELAY MENU
contains the options necessary to select the actions
performed by the System Start (SYS START
),
Fault Alarm (FLT ALARM) and Auxiliary (AUX)
Relays in the ACS.
3.12.1 SYS START TEMP
If an Outdoor Air Sensor is installed, this menu option is used to select the Outdoor
Temperature below which the System Start Relay is allowed to activate (close), provided that
the SYS START OPTION conditions specified below are satisfied. The percent level will always
remain at 0% until the System Start Relay is activated The System Start Relay will open if the
Outdoor temperature is above the value set for this option.
3.12.2 SYS START OPTION
The
SYS START OPTION
can be set to
TEMP ONLY
or
TEMP AND LOAD.
Selecting
TEMP
ONLY
means the System Start Relay will be active whenever the Outdoor Temperature falls
below the System Start Temperature (SYS START TEMP).
Selecting
TEMP AND LOAD
will cause the System Start Relay to activate if the Outdoor
Temperature falls below the System Start Temperature and the Percent of Load (Operating
Menu) is at or above the
LOAD START PCT
(Calibration Menu
)
. It will deactivate (open) the
System Start Relay when the Percent of Load goes below the
LOAD START PCT.
3.12.3 SYS START INTLK
The
SYS START INTLK
selects the Interlock associated with the System Start Relay activation
when
SYS INTLK CONFIG
is set for
START ENABLED
. Available settings include
,
INTERLOCK 1 (default), INTERLOCK 2,
or
INTERLOCK 1&2.