AERCO Control System (ACS)
CHAPTER 3
: Operation
11/22/2017
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, New York 10913
Page 57 of 139
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3.9.18 DHW SIGNAL (Domestic Hot Water Signal)
NOTE
This function apples only to the C-More Controller, although it
is not currently implemented at this time.
This setting tells the ACS the type of signal to send to the combination (DHW) boilers in order to
allow them to do domestic water heating. If NO SIGNAL is selected, the ACS will just stop
sending the Modbus fire ra te (percent level) signal to the boiler during this time. If SPECIAL
SIGNAL is selected, the ACS will send an AERCO-defined signal that the boiler control will
recognize as the signal to do domestic hot water heating. The default is NO SIGNAL.
3.9.19 NUM DHW PRIORITY (Number of DHW Priority Boilers)
This shows for OPTION 2 only. It selects the amount of boilers from the previously selected
NUMBER DHW BOILERS that are to be used as DHW PRIORITY boilers.
3.9.20 VALVE WAIT STATES
This setting tells the ACS whether to keep a fired boiler running while waiting for the valve to
transition or to shut it down. Select ON to keep it running and OFF to shut it down.
3.9.21 SYS RELAY OPTION (System Relay Option)
This selection will only show when OPTION 1 is selected for DHW OPTION. It allows one to
choose whether the SYS RELAY output from the ACS will be acting as the DHW valve close
contact or will be operating normally as the contact to indicate when the boiler plant system is
enabled. The default is DHW VALVE CLOSE in which case the ACS will use the SYS RELAY
as the valve closure contact and the AUX RELAY output as the valve open contact. If the
hydronic valve being controlled has a spring-return closure or other non-powered closure, one
would select NORMAL since the SYS RELAY contact would not be needed to close the valve.
BOOST TEMP
3.9
This option only shows when OPTION 3 is selected for DHW OPTION. The BOOST TEMP tells
the minimum water temperature desired in the primary loop or heat exchanger of the domestic
heating system in order to heat the water to the desired temperature. This temperature would
normally be at least 10 degrees above the desired DHW setpoint. The default setting is 140°F.
If the current setpoint is below the set BOOST TEMP, the BOOST TEMP will be used as the
new setpoint. If the ACS's setpoint is above the BOOST TEMP setting, no change will be made
to the setpoint while the domestic system is calling for heat. When the domestic system stops
calling, the setpoint will go back to normal.
3.10.1 RET TEMP BST DIS
(RETURN TEMPERATURE BOOST DISABLE)
This setting defines a return temperature above which the Boost will be disabled. If the return
temperature exceeds the RET TMP BST DIS setting, the boost will be deactivated and the fault
message will be displayed. The fault may be cleared by cycling the boost input (Interlock 2) or
by pressing the “Clear” key. The default setting is OFF.
