50
£
Option 12.0 - Boiler sequencing enable (0 - 1)
This option parameter enables boiler sequencing control via the RS485 serial communications inter-
face.
Option 12.1 - Boiler priority (0 - 9)
This option parameter determines the order in which the boiler will be fired when operating under
sequence control. After the lead boiler, the next boiler to be fired is the boiler with the next highest
priority. The examples below show how the priorities are chosen for a ten boiler sequencing system.
e.g. 1: If the lead boiler priority is 0, the sequence is: LEAD, 1, 2, 3, 4, 5, 6, 7, 8, 9.
e.g. 2: If the lead boiler priority is 5, the sequence is: LEAD, 6, 7, 8, 9, 0, 1, 2, 3, 4.
Option 12.2 - Low fire burner power output (0.0 - 99.9MW)*
This option parameter must be set to the power output from the burner when operating at low fire. It
is used when boiler sequencing is enabled to determine the switching points for the boiler.
Option 12.3 - High fire burner power output (0.0 - 99.9MW)*
This option parameter must be set to the power output from the burner when operating at high fire. It
is used when boiler sequencing is enabled to determine the switching points for the boiler.
Option 12.4 - Lead boiler select (0 - 1)
When the unit is under sequence control, setting this option parameter to 1 will force the unit to
assert itself as the lead boiler.
If this option parameter is set to 1 AND/OR an auxiliary input is high (assuming the auxiliary input
has been configured for lead boiler select - see option parameters 10.1 and 10.2), the unit will assert
itself as the lead boiler.
If two or more units have been set as lead, sequencing is disabled.
Option 12.5 - Standby low limit control value (0 - 999 / 00.0 - 99.9 / 0.00 - 9.99)
If the unit is placed in standby mode by boiler sequence control, the boiler’s pressure is maintained
between two limit values.
This option parameter determines the pressure at which the boiler will be turned on when in standby
mode.
Option 12.6 - Standby high limit control value (0 - 999 / 00.0 - 99.9 / 0.00 - 9.99)
If the unit is placed in standby mode by boiler sequence control, the boiler’s pressure is maintained
between two limit values.
This option parameter determines the pressure at which the boiler will be turned off when in standby
mode.
Option 12.7 - Sequencing ON delay (5 - 15 minutes)
When the unit is under sequence control, this parameter determines the minimum amount of time
between one slave coming ON and the next slave coming ON. This parameter is not used on a two
boiler system because there is only one slave to turn on or off.
Option 12.8 - Sequencing OFF delay (1 - 15 minutes)
When the control is under sequence control, this parameter determines the minimum amount of time
between one slave coming OFF and the next slave coming OFF. This parameter is not used on a two
boiler system because there is only one slave to turn on or off.
0
Sequence control disabled. The unit operates in a stand-alone mode.
1
Sequence control enabled. The unit will modulate and sequence its boiler according to instructions received from the lead boiler.
If communication with the lead boiler is lost, the unit operates in stand-alone mode.
