AERCO BMS 168 - Manual (Page 45)

NOTE
Steps 5, 6 and 7 scale the 20 mA
Remote Signal to the selected HDR
HIGH LIMIT and HDR LOW LIMIT
settings.
5. Select the desired header high
temperature limit setting using the ▲
and ▼ arrow keys. The selected
temperature will be equal to a 20 mA
Remote Signal.
6. Press and release the HDR TEMP
LIMIT key again. HDR LOW LIMIT is
displayed with the present low
temperature limit setting.
7. Select the desired header low
temperature limit setting using the ▲
and ▼ arrow keys. The selected
temperature will be equal to a 4 mA
Remote Signal.
5.3 S
ETUP
F
OR
C
ONSTANT
S
ETPOINT
M
ODE
In this mode of operation, only a header
sensor is required. Entries in this mode are
required for Header Set Mode, Boiler
Operating Mode and Header Reference
Temperature.
5.3.1 Entering Header Set and Boiler
Operating Modes
These selections are made with the BMS in
the System Configuration mode. Proceed as
follows:
1. Press the CONFIG SYS key to enter the
System Configuration mode. The
CONFIG SYS key LED will illuminate.
2. Place SYSTEM CONFIGURATION
OVERLAY on the BMS front panel.
3. Press the HDR SET MODE key once.
HEADER SET MODE is displayed with
the presently stored mode selection.
4. While observing the display, toggle the
HDR SET MODE to CONSTANT
SETTEMP using the ▲ or ▼ arrow key.
5. Press the BLR OP MODE key. BOILER
OP MODE is displayed with the
presently stored mode selection.
6. Select the PARALLEL, SEQUENTIAL or
COMBINATION MODE using the ▲ or
▼ arrow key.
7. Press the CONFIG SYS key to exit the
System Configuration mode. The
CONFIG SYS LED will go off.
8. Remove the SYSTEM CONFIG-
URATION overlay from the BMS front
panel.
5.3.2 Entering Header Reference
Temperature (Setpoint)
The Header Reference Temperature (Set-
point) is entered as follows:
1. Enter Field Adjust mode by pressing the
FIELD ADJ key. Verify that the key LED
illuminates.
2. Press the REF TEMP key. The display
will show the present HEADER REF.
TEMP stored in memory.
3. Set the desired setpoint temperature
using the ▲ and ▼arrow keys. The set-
point temperature can be adjusted from
40°F to 220°F.
4. Initialize the BMS using the procedures
in paragraph 5.5.
5.4 C
ONFIGURING
B
OILERS
F
OR
P
ULSE
W
IDTH
M
ODULATION
(PWM)
Configuring each boiler for BMS control
using Pulse Width Modulation (PWM)
differs, depending on the Control System
used by each AERCO boiler. Refer to the
appropriate Operation and Maintenance
Manuals provided with the boilers being
used. If the KC1000 or Benchmark boilers
are equipped with the newer C-More
Control Systems, proceed to paragraph
5.4.1. However, if the boilers are equipped
with the older Modular Control Systems,
proceed to paragraph 5.4.2.
5-3