Application Note: Controlling 2 Boilers Lead/Lag

Solution:

Using a 75F Edge 10, a basic Boiler Plant can be controlled in the form of a simple configurable controller.  The Edge 10 will come pre-programmed for a true plug-and-play experience and without the need to self-program or accessing the wire sheets on the Edge 10.  We will also provide parameters for system tuning on the CCU so direct access to the Edge 10 is not required.  All points will be viewed and configurable on the CCU and through Facilisight.

Note:

• This solution does not require an internet connection to the Edge 10, only to the CCU.
• The boiler plant may have control for up to 2 Boilers or Boiler Systems.
• One mixing valve may be controlled if needed.
• Sequence will control boilers on lead/lag sequences.
• This solution does not include pump control, but does provide an output to start a pump system.  There will be a 1 minute time delay after pumps are commanded on for the flow switch to be proven before the boilers will be enabled.
• For Pump Control, see the following Application Note:
  • https://support.75f.io/hc/en-us/articles/21254306642963-Application-Note-Pump-Lead-Lag-Standby-Controller

System Points List:

Hardwired Inputs:

• Outdoor Air Temperature
• Supply (Leaving) Water Temperature
• Return (Entering) Water Temperature
• Boiler Alarm
• Loop Flow Switch

Digital Outputs:

• Boiler 1 Enable
• Boiler 2 Enable
• System Enable Output

Analog Outputs:

• Loop Pump Speed
• Mixing Valve Position

Variables/Setpoints

• Supply (Leaving) Water Temperature Setpoint
• Outdoor Air Temperature for System Enable
• Boiler Rotational Sequence (Rotate manually or automatically based on runtime)
• Manual Boiler Rotation
• Runtime Hours for Boiler Rotation
• PID Loop Tuning for Mixing Valve
  • Proportional
  • Integral
  • Derivative
  • Bias
  • Minimum Output
  • Maximum Output
  • Ramp Time (Minutes)