Boiler Control Instruction & Operation Manual, Rev 1
Page
37
of 64
Setup & Tuning
Parameter Adjustment
Modulation Continued
Factory
Setting
Range /
Choices
Parameter and Description
5 (ºF)
0 to (Stepped
Modulation
Start Offset
– 6)
Stepped Modulation Recycle Offset
This feature helps avoid manual reset and soft lockouts by recycling the boiler when the
temperature i
s “Stepped Modulation Recycle Offset” degrees below the Limit setting.
For example, when the setting is 5 F the boiler will recycle when supply temperature is
5 F below the High Limit.
Applicable to the following measurements.
Supply Temperature (High Limit 210 F)(see
Note
below),
Differential Temperature (Differential Temperature Limit 100 F),
Stack Temperature (Stack Limit 230 F),
Note
: This feature is not active for Supply temperature when it is the modulation sensor.
For example, this feature is active when Header Sensor is selected as modulation sensor,
when a boiler is a slave, when a boiler is responding to a remote modulation demand (4-
20mAdc or Modbus).
Disabled
Enable
Disable
CH Slow Start Enable/Disable
This parameter enables or disables the slow start limit function for Central Heat and
Sequence Master demand sources. It uses the CH Low Fire Hold Rate parameter as
the starting point for the slow start.
Disabled
Enable
Disable
DHW Slow Start Enable/Disable
This parameter enables or disables the slow start limit function for DHW demand source. It
uses the DHW Low Fire Hold Rate parameter as the starting point for the slow start.
20°
0 to 180
Slow Start Degrees
If slow start limiting is enabled and the supply temperature is less than the temperature
provided by subtracting this number of degrees from the setpoint, then slow start rate
limiting is effective. Whenever the supply temperature is above this value, slow start
limiting has no effect.
200
%/min.
0 to 1000
Slow Start Ramp
When slow start limiting is in effect, the modulation rate will increase no more than the
amount per minute given by this parameter. Although provided as a per-minute value, the
Control will calculate and apply this as a stepped function using step duration of 10
seconds.
1
Disable
PWM to 4-
20mA
PWM to 0-10V
LL Rate to 4-
20mA
LL Rate to 0-
10V
Analog Rate Tracking
Allows external system to monitor firing rate.
Disable
No signal is sent to terminals
PWM to 4-20mA
Firing rate provided using 4-20mA signal
PWM to 0-10V
Firing rate provided using 0-10V signal
LL Rate to 4-20mA
Sequence Master demand is provided using 4-20mA signal
LL Rate to 0-10V
Sequence Master demand is provided using 0-10V signal
0.1
0
– 10 tenths
Analog Input Hysteresis
This parameter adjusts the amount of hysteresis applied remote control input when
modulation source is set to 4-20mA. A zero value disables this feature.
1.0
0
– 40 tenths
Analog output hysteresis
This parameter adjusts the amount of hysteresis applied to the PID output when a non-
PWM modulation is selected. The value determines how much the PID is required to
change in a new direction before the output will change. A zero value disables this feature.