6.3 LEAD LAG SETUP
The following components are needed for a Lead Lag setup
1) 10k System Sensor
Turn off all the boilers before beginning the setup process.
To setup the DynaFlame® Lead Lag system follow the
instructions:
System Sensor
Insert the supplied 10k system sensor into the building
loop. The wires coming out of the system sensor should be
connected to Sys/Outdr terminals in the junction box.
NOTE
The use of a system sensor is required in lead lag
operation.
1) When variable speed main circulators ARE NOT
used the system sensor is to be placed into the
return system piping.
2) When variable speed main circulators are used
the system sensor is to be placed into the supply
system piping.
All SOLA controllers are programmed with a default
address of 1. The address of the slave controllers in the
system must have a unique address (1..8).
Sequence of Operation:
When a boiler is set as Lead Lag Master = Enabled and
Modbus address = 1, the controller of this boiler will drive
the lead lag operation.
The outdoor temperature sensor connected to the slave
boiler 2 (ie. B-2) will be the outdoor sensor for the lead lag
system
• The system temperature sensor connected to
boiler 1 in terminals labeled “Outdr/Sys” in the
junction box will be the control sensor for lead lag
operation.
• The start/stop signal connected to boiler 1 at
terminals labeled “Remote Operator” will be the
heat demand input for lead lag operation.
When demand for heat is present the lead boiler will start
and uses the lead lag parameters for boiler modulation.
After a period of “Interstage delay” the master boiler
compares the lead lag temperature with the lead lag set
point and will check if:
1) An additional boiler is needed
Lead lag temp < Lead lag setpoint – Add stage
Error threshold
2) Number of boilers remain the same
Lead lag temp > Lead lag setpoint – Add stage
Error threshold AND
Lead lag temp < Lead lag setpoint + Drop stage
Error threshold
3) A boiler should stop
Lead lag temp > Lead lag setpoint + Drop stage
Error threshold
4) All boilers off
Lead lag temp > Lead lag setpoint + off hysteresis
If the lead lag master system is interrupted the remaining
boilers will operate as standalone boilers based on the
Central Heat or DHW parameters when set to “Enabled”.
Rotation
Rotation time is configurable based on equalized run time
(default) or a fixed rotation schedule.
Interstage Delay
The length of time to wait between requesting a slave
SOLA to fire and detecting that it has failed to start.
(Default: 2 minutes)
Base Load Rate
When a call for heat is initiated the lead boiler runs at the
desired base load rate (Default: 80%) and continues to
operate in this fashion based on the above 4 scenarios. If
the lead lag temperature is not satisfied a second boiler is
fired at they would both operate at 80% fire rate.
Slave State
Slave Status Manager
Unknown Table entry is unused or empty
Available Slave is operational and ready to use
Add Stage Stage is getting ready to fire