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MODE OF OPERATION
7. Press the CHANGE key. The display will
begin to flash.
8. Use the ▲ and ▼ arrow keys to select the
desired Building Reference Temperature.
9. Press ENTER to save any changes.
10. Next, scroll through the Configuration Menu
until the display shows Reset Ratio.
11. Press the CHANGE key. The display will
begin to flash.
12. Use the ▲ and ▼ arrow keys to select the
Reset Ratio determined in step 5.
13. Press ENTER to save the change.
Refer to paragraph 3.3 for detailed instructions
on menu changing.
5.3 CONSTANT SETPOINT MODE
The Constant Setpoint mode is used when a
fixed header temperature is desired. Common
uses of this mode of operation include water
source heat pump loops, and indirect heat
exchangers for potable hot water systems or
processes.
No external sensors are required to operate in
this mode. While it is necessary to set the
desired setpoint temperature, it is not necessary
to change any other temperature-related func-
tions. The unit is factory preset with settings that
work well in most applications. Prior to changing
any temperature-related parameters, other than
the setpoint, it is suggested that an AERCO
representative be contacted. For descriptions of
temperature-related functions and their factory
defaults, see Appendices A and E.
5.3.1 Setting the Setpoint
The
setpoint
temperature
adjustable from 40°F to 240°F. To set the unit
for operation in the Constant Setpoint Mode, the
following menu settings must be made in the
Configuration Menu:
MENU OPTION
Boiler Mode
Constant Setpoint
Internal Setpt
Select desired setpoint
using ▲ and ▼ arrow
keys (40°F to 240°F)
Refer to paragraph 3.3 for detailed instructions
on changing menu options.
5.4 REMOTE SETPOINT MODES
5-2
of
the
unit
is
SETTING
The unit's setpoint can be remotely controlled by
an Energy Management System (EMS) or
Building Automation System (BAS). The Remote
Setpoint can be driven by a current or voltage
signal within the following ranges:
4-20 mA/1-5 Vdc
0-20 mA/0-5 Vdc
The factory default setting for the Remote
Setpoint mode is 4 - 20 mA/1 - 5 Vdc. With this
setting, a 4 to 20 mA/1 to 5 Vdc signal, sent by
an EMS or BAS, is used to change the unit's
setpoint. The 4 mA/1V signal is equal to a 40°F
setpoint while a 20 mA /5V signal is equal to a
240°F setpoint. When a 0 to 20 mA/0 to 5 Vdc
signal is used, 0 mA is equal to a 40°F setpoint.
In addition to the current and voltage signals
described above, the Remote Setpoint mode
can also be driven by a RS485 Modbus Network
signal from an EMS or BAS.
The Remote Setpoint modes of operation can be
used to drive single as well as multiple units.
NOTE
If a voltage, rather than current signal is
used to control the remote setpoint, a DIP
switch adjustment must be made on the
CPU Board located in the Control Panel
Assembly. Contact your local AERCO
representative for details.
In order to enable the Remote Setpoint Mode,
the following menu setting must be made in the
Configuration Menu:
MENU OPTION
Boiler Mode
Remote Setpoint
Remote Signal
4-20mA/1-5V,
0-20mA/0-5V, or
Network
Refer to paragraph 3.3 for detailed instructions
on changing menu options.
SETTING
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