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®
WARNING: Only use the large tolerance setting if an inverter error of up to±55 will not
cause unsafe combustion.
Option 22.2 - Inverter error tolerance (0 / 1)*
This option parameter affects all inverters connected to the unit.
0
- Small tolerance (normal setting). The unit will perform a safety shutdown if the
inverter positioning error exceeds ±30 for 15 seconds or ±55 for 1 second (units conform to those
seen on the display).
1
- Large tolerance. The unit will perform a safety shutdown if the inverter positioning
error exceeds ±55 for 1 second (units conform to those seen on the display).
Note: Only use the large tolerance setting if an inverter error of up to ±55 will not cause unsafe
combustion.
Option 22.3 - Inverter closed loop gain (15 – 125%)*
This option parameter affects all inverters connected to the unit.
For normal operation, use 100%. If the inverter control is unstable, reducing this value has the effect
of damping the inverter’s response as its speed approaches its setpoint.
Option 22.4 - Inverter stop time (0 – 100 seconds)*
Determines the minimum time between a burner shutdown and subsequent startup. Set this parame-
ter to give the inverter sufficient time to stop before the burner restarts.
Option 25.0 - Boiler sequencing enable (0 - 1)
This option parameter enables boiler sequencing control via the RS485 serial communications inter-
face.
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.
Option 25.1 - 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 25.2 - Low fire burner power output (0.0 - 99.9MW)*
Option 25.3 - High fire burner power output (0.0 - 99.9MW)*
These option parameters must be set to the power output from the burner when operating at low fire
and at high fire. These values are used by boiler sequencing to determine the switching on and off
points for the boiler.
Option 25.4 - 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 25.5 - Standby low limit control value (0 - 999 / 00.0 - 99.9 / 0.00 - 9.99)
