AERCO Control System (ACS)
CHAPTER 1
: ACS General Information
11/22/2017
AERCO International, Inc.
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100 Oritani Dr.
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Blauvelt, New York 10913
Page 13 of 139
OMM-0081_0F
Phone: 800-526-0288
GF-131
1.4.3 Retention of Menu Option Settings
By using non-volatile memory, the ACS retains program and menu settings during shut-down or
when input AC power is interrupted. Settings can be retained for more than 2 years.
1.4.4 Configuration Options
Four different configuration options can be selected to match the needs of any closed-loop
system. These configurations are: Outdoor Reset, Constant Setpoint, Remote Setpoint via a 4-
20 Ma input and Remote Setpoint via Modbus.
Three different domestic hot water (DHW) options are selectable for controlling the combination
boilers and valves that are being used to provide heated domestic water.
1.4.5 Sequential and Parallel Operation
Boilers can be programmed for either sequential or parallel operation using the ACS keypad
controls. When set for sequential operation, the boilers are brought on-line one at a time as
needed. When set for parallel operation, the boilers are all brought on-line together at the same
firing rate.
1.4.6 Accuracy
Using PID (Proportional Integral Derivative) and Ramp-Up/Ramp-Down Modulation Control
Algorithms, the ACS provides dynamic responses to all changes in boiler plant operation.
Header temperatures, as well as percentages of boiler input are precisely controlled with
virtually no over-shoot or short-cycling of boiler units. A header temperature accuracy of ±2°F is
virtually assured during continuous plant operation.
1.4.7 Sequential Operation
When operated sequentially, The ACS stages boilers on and off at selectable firing rate
percentages. The result is a seamless transition with undetectable room temperature changes.
In addition, when in sequential mode, the ACS sequences boilers using a first-on, first-off basis,
thereby equalizing the accumulated run time of all boilers in the plant.
The ACS also continuously monitors the number of Boilers that are available for operation. In
the event of a boiler malfunction, or required servicing, the ACS automatically compensates for
a lack of response from any unit and brings on the next available boiler to satisfy the demand.
This feature operates in both sequential and parallel modes.
1.4.8 Fault Alarm Surveillance
If an EMS or BAS is not used with the ACS to monitor faults, a Fault Alarm Relay can be
activated thereby notifying facility managers of faults associated with the ACS.
1.4.9 ACS Programming Via RS232 Port
If desired, the ACS can be programmed by connecting a Laptop Computer or other terminal
emulation device to the RS232 Port terminals on the ACS. Detailed set-up instructions and
available command listings are provided in Appendix G. Most settings are also programmable
using Modbus.
