AERCO Control System (ACS)
CHAPTER 3
: Operation
Page 52 of 139
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, New York 10913
11/22/2017
GF-131
Phone: 800-526-0288
OMM-0081_0F
3.8.5 RESET RATIO
This menu option is displayed only if the
HEADER SET MODE
is set to
OUTDOOR RESET.
The RESET RATIO
option setting defines the ratio of the increase in Header temperature with
respect to each degree decrease in Outdoor temperature starting from the Building Reference
Temperature (
BLDG REF TEMP
).
The Reset Ratio is adjustable from 0.3 to 3.0. (Default = 1.2). The Reset Ratio Charts provided
in Appendix C are suitable for most applications. However, if a special reset schedule is desired,
the calculation method described in Appendix C must be used.
3.8.6 BLDG REF TEMP
The
BLDG REF TEMP
menu option is only displayed when the
HEADER SET MODE
is set to
OUTDOOR RESET.
This option is used to set the Building Reference Temperature
(BLDG REF
TEMP)
to the desired value from 40°F to 220°F. (Default = 70°F).
3.8.7 REMOTE SIGNAL
The
REMOTE SIGNAL
menu option is only displayed when the
HEADER SET MODE
is set to
REMOTE SETPT.
When displayed, this option is used to select the controlling remote signal: to
4 – 20 mA or MODBUS. (Default = 4-20 mA).
3.8.8 OFFSET ENABLE
The
OFFSET ENABLE
menu option is used to turn ON, or turn OFF the Setpoint Temperature
Offset feature. (Default = OFF)
3.8.9 OFFSET MENU OPTIONS
The Field Adjust Menu contains a series of menu options which permit an offset schedule to be
set up for a 7-day period (Sunday through Saturday). For each day (Sunday – Saturday), these
options include:
•
OFFS TEMP [Setpoint Offset Temperature (-50°F to +50°F)]
•
ON HOUR (00 to 23)
•
ON MINUTE (00 to 59)
•
OFF HOUR (00 to 23)
•
OFF MINUTE (00 to 59)
Normally, if an Offset Schedule is used, it is controlled automatically using the set-up
procedures described in the paragraph titled “Setting Up An Offset Reset Schedule” However, if
desired, the header offset can be controlled manually by connecting a switch across the SET
BACK wiring terminals 13 and 14 as shown in the wiring diagram in Appendix E. If a manual
offset is used, refer to the paragraph titled “Manual Offset”.
3.8.10 SETTING UP AN OFFSET SCHEDULE
The steps involved in setting up an automatic reset schedule consists first of selecting the
temperature offset and then entering the start and stop times for which the offset will be in
effect. Note that the ACS uses a 24-hour clock (00;00 to 23:59). The steps are outlined below.
In this example, the setpoint temperature is being offset -15°F on Sunday from 12:01 AM
(00:01) to 8:00 AM (08 hrs).
