Fan Speed Modulation Parameters - CleaverBrooks CFC Operation, Service & Parts Manual

Parameter
Modulation output
Standby rate
Prepurge rate
Lightoff rate
Firing rate control
Manual firing rate
CH Maximum modulation rate
DHW Maximum modulation rate
Minimum modulation rate
Postpurge rate

Fan Speed Modulation Parameters

These parameters are used only when fan speed is selected
as the modulation output.
Parameter
Absolute maximum fan speed
Absolute minimum fan speed
Table 26. Modulation Output Parameters.
Fan Speed, 4-20mA, 0-10V
This parameter selects the type of modulation output. The Falcon software responds by
driving the appropriate circuit to provide modulation of firing rate.
This parameter also affects the interpretation or the type of all parameters which specify
rates. These may be provided either as motor RPM or as percentage values, depending on
the type of modulation output selected.
A programmed value is valid only as a fan speed, or as a percent, but not both. Thus if a
system is set up using fan speed values, and then the modulation output parameter is
changed to select one of the analog outputs, then all of the fan speeds become "Invalid".
Similarly, parameters that were set up as percentages are invalid when interpreted as fan
speeds.
RPM or %
This parameter specifies the analog output or fan speed used during Standby. If the control is
receiving commands via the LL slave module to operate at a given rate, that parameter has
higher priority and this parameter is ignored.
For a PWM fan system: This rate command will not run the motor.
For an analog rate output system:
• the output rate is 4mA or 0V
Else when Standby rate is non-zero then:
• the output rate is determined by the analog output mapping and the mA or V rate analog is
applied to the motor.
RPM or %
This parameter specifies the analog output or fan speed used during prepurge.
RPM or %
This parameter specifies the analog output or fan speed used during ignition.
Auto, Manual in Run, Manual in Run and Standby
If this parameter is set to either of the manual options, then the burner's firing rate during
modulation in the Run state is the rate given by the Manual firing rate parameter. If the
Manual in Run and Standby option is chosen, the firing rate output is also controlled by the
manual firing rate parameter during the Standby condition; however this applies only to the
normal, idle Standby condition and not to a Standby Hold condition, wherein the burner is
preparing to fire but cannot leave standby because of something abnormal. In the latter case
the rate is driven by the burner control sequencer. A manual rate does not generate
demand—to fire at this rate demand must be present from another source. When set to
"Auto" the manual firing rate parameter is ignored.
RPM or %
This parameter specifies the analog output or fan speed during burner modulation or standby,
when firing rate control specifies manual mode.
RPM or %
These parameters provide the limits of analog output or fan speed during modulation. The
minimum modulation rate is the same for both CH and DHW.
RPM or %
This parameter specifies the analog output or fan speed used during postpurge.
Table 27. Fan Speed Modulation Parameters.
RPM
The fan will never operate above the RPM provided by this parameter, regardless of the rate
request. The maximum speed is 12000 RPM.
RPM
The fan will never operate below the RPM provided by this parameter, regardless of the rate
request, except by commanding it to turn off. The minimum speed is 500 RPM.
Comment
Comment
51
CB FALCON
750-265