AERCO BMS II BOILER - Manual (Page 42)

OPERATION
3-10
Setting Up An Offset Schedule
The basic steps involved in setting up an automatic reset schedule consist first selecting the temperature
offset and then entering the start and stop times for which the offset will be in effect. Keep in mind that
the BMS II 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)
1. Scroll through the FIELD ADJUST MENU and select OFFSET ENABLE. Set this option to ON.
2. Next, scroll to SUN OFFS TEMP and set the Offset Temperature to -15°F.
3. Press the
▲ arrow key. SUN ON HOUR will be displayed. Set the HOUR to 00.
4. Press the
▲ arrow key again. SUN ON MINUTE will be displayed. Set the MINUTE to 01.
5. Press the
▲ arrow key again. SUN OFF HOUR will be displayed. Set the HOUR to 08.
6. Press the
▲ arrow key again. SUN OFF MINUTE will be displayed. Set the MINUTE to 00.
7. Repeat steps 2 through 6 to set offset schedules for the remaining days of the week. Different offset
temperatures and ON/OFF times can be set for each day if desired.
Manual Offset
If a switch is connected across terminals 13 and 14 on the BMS II, the offset temperature can be
controlled manually. To set up a manual offset schedule, proceed as follows:
1. Scroll through the FIELD ADJUST MENU and select OFFSET ENABLE. Set this option to ON.
2. Next, scroll to SUN OFFS TEMP and set the desired Offset Temperature. A different Offset
Temperature can be set for each day if desired.
3. Scroll through the remaining days of the week and set the desired offset temperature for each day.
Once programmed as described above, closing the SET BACK switch will enable the programmed OFFS
TEMP for that day. Opening the SET BACK switch will disable the OFFSET and the Header Setpoint will
return the selected INTERNAL SETPT temperature.
3.9 CONFIGURATION MENU
The Configuration Menu contains options which set the Boiler operating modes start/stop levels and
maximum allowable power input. In addition, it contains a Fail Safe Mode feature which is used to select
the default mode when the controlling input source is lost.
BOILER OP MODE
The BOILER OP MODE menu option sets the control operation method for the BMS II. to either
SEQUENTIAL or PARALLEL MODE.
Parallel Mode
When PARALLEL MODE is selected, all boilers are simultaneously started by the BMS II. The BLR
START LEVEL and BLR STOP LEVEL set in the Configuration Menu (see below) have no effect when in
this mode. Regardless of the number of Boilers in the plant, the turn-down ratio in the Parallel Mode is
fixed at 20:1 for KC1000 Series Boilers (except 11:1 for KC Low NOx). For Benchmark Series Boilers,
the turn-down ratio is fixed at 20:1 for BMK2.0, 2.0LN, and 1.5LN Boilers. However, for BMK3.0LN Boilers
the turn-down ratio is fixed at 15:1.