AERCO C-More Controls - Manual (Page 28)

C-MORE CONTROL PANEL OPERATION
SECTION 5 -
INPUT/OUTPUT INTERFACES & OPERATING MODES
5.1 INTRODUCTION
This Section provides descriptions of the
Input/Output (I/O) wiring connections which can
be made at the Input/Output (I/O) Box included
with the C-More Control Panel. For KC Series
units, the I/O Box is located on the left side of
the unit. For Benchmark Series units, the I/O
Box is located on the front of the unit behind the
door.
Also included in this Section are descriptions of
the available operating modes which can be set
up for Water Heaters and Boilers utilizing the C-
More menus.
5.2 I/O INTERFACES
All wiring connections are made at the terminal
strips contained in the I/O Box. The I/O Box
cover contains a connection diagram as shown
in Figure 5-1. Refer to this diagram when
making all field wiring connections to the I/O
Box. The connections shown in Figure 5-1 are
described in the following paragraphs.
CAUTION!
DO NOT make any connections to the I/O
Box terminals labeled “NOT USED”.
Attempting to do so may cause equipment
damage.
5.2.1 OUTDOOR SENSOR IN
An outdoor air temperature sensor (AERCO Part
No. 122790) will be required mainly for the
Indoor/Outdoor Reset Mode of operation for
boilers. It can also be used with another mode if
it is desired to use the outdoor sensor
enable/disable feature. This feature allows the
boiler to be enabled or disabled based on the
outdoor air temperature. The factory default for
the outdoor sensor is DISABLED. To enable the
sensor or choose a system start temperature,
see the Configuration Menu in Table 2-3.
The outdoor sensor may be wired up to 200 feet
from the boiler. It is connected to the OUTDOOR
SENSOR IN and SENSOR COMMON terminals
in the I/O Box (see Figure. 5-1). Wire the sensor
using a twisted shielded pair cable of 18-22
AWG wire. There is no polarity to observe when
terminating the wires. The shield is to be
connected only to the terminals labeled SHEILD
in the I/O Box. The sensor end of the shield
must be left free and ungrounded.
When mounting the sensor, it must be located
on the North side of the building where an
average outside air temperature is expected.
The sensor must be shielded from direct sunlight
as well as impingement by the elements.
If a shield is used, it must allow for free air
circulation
.
5.2.2 AUX SENSOR IN
The AUX SENSOR IN terminals can be used to
add an additional temperature sensor for
monitoring purposes. This input is always
enabled and is a view only input that can be
seen in the operating menu. The sensor must be
wired to the AUX SENSOR IN and SENSOR
COMMON terminals. It must be similar to
AERCO BALCO wire sensor P/N 123449. A
resistance chart for this sensor is provided in
Appendix D.
5.2.3 ANALOG IN
The ANALOG IN + and – terminals are used
when an external signal is used to drive the
firing rate (Direct Drive Mode- Boiler Only) or
change the setpoint (Remote Setpoint Mode) of
the unit.
Either a 4 to 20 mA / 1 to 5 VDC or a 0 to 20
mA/ 0 to 5 VDC signal may be used to vary the
setpoint or firing rate. The factory default setting
is for 4 to 20 mA / 1 to 5 VDC, however this may
be changed to 0 to 20 mA / 0 to 5 VDC using the
Configuration Menu described in Sections 2 and
3. If voltage rather than current is selected as
the drive signal, a DIP switch must be set on the
PMC Board located inside the Control Box.
Refer to Appendix F for information on setting
DIP switches.
All supplied signals must be floating (unground-
ed) signals. Connections between the source
and the unit’s I/O Box must be made using
twisted shielded pair wire of 18 – 22 AWG, such
as Belden 9841(see Fig. 5-1). Polarity must be
maintained and the shield must be connected
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