Section 4 — Commissioning
4-18 Part No. 750-363
4.12 FALCON CONTROL FUNCTIONS AND CUSTOMER INTERFACE
Following is a brief overview of the Falcon control features on ClearFire boilers. Please refer to the Falcon
Control manual for more detailed explanations.
• Set Point
• Time-of-Day (TOD) Set Point
• Hysteresis On and Hysteresis Off
• PID modulation control
• Remote Enable and Remote 4-20mA Input
• Remote Modulation
• Remote Set Point
• Rate Limiting/Override
• Configurable pump/auxiliary relay contacts
• Annunciator
• Diagnostics
• Lockout/Alarm History
• Trend Analysis
• Modbus communications
• Lead/Lag Control for up to 8 boilers
• DHW demand priority
Set Point, TOD Set Point, Hysteresis On, Hysteresis Off, and PID load control
The set point is the value that the boiler’s PID load control attempts to maintain in order to meet system
demand. The modulating set point can be adjusted at the Operation page or under the Central Heat
Configuration parameter group. No password is required to change the set point. To change the set point
at the Operation page, press the set point value next to “Normal”. Clear the current value and enter the new
value. Press <OK> to establish the new set point.
The Time-of-Day (TOD), or setback, set point is an alternative set point that is enabled when a remote
contact connected to terminals J10-2 & J10-3 is closed (Refer to Figure 2-10 CFLC wiring diagram). When
the circuit is open, the boiler control reverts back to the normal set point. The TOD set point can be adjusted
at either the Operation page or under the Central Heat Configuration parameter group. Service level
password login may be required to change this parameter.
The hysteresis on and hysteresis off points can only be changed under the Central Heat Configuration
parameter group and require a login with the Service level password. Hysteresis on is the differential below
the current set point at which the boiler will restart following an off cycle. Hysteresis off is the differential
above the current set point at which the boiler will cycle off – effectively the boiler’s operating limit. These
two parameters apply to both the normal and TOD set points. To minimize the frequency of cycling the boiler
on and off, the values of either, or both, of these settings may be increased. Default settings for Hysteresis
on and off are 5 deg F and 15 deg F, respectively.
The PID (Proportional-Integral-Derivative) load control operates on the demand source’s modulation rate.
Under Central Heat configuration, the PID gain values can be adjusted to match the desired modulation
response. The default gain value settings of P=25, I=25 & D=0 have proven to work well with typical
single boiler heating applications.
Decreasing the PID gain values slows down the controller’s response to a change in load demand.
Increasing the gain values causes more aggressive control, though setting the values too high can lead to
‘overshoot’ and unnecessary cycling.
Remote Enable and Remote 4-20mA Input
Remote enable and Remote 4-20mA input allow the boiler to be sequenced and/or controlled from a
separate boiler room controller or building management system. The 3-position Demand switch at the front
of the control panel determines whether the boiler is off, in local, or under remote control. When in the
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