Boiler Control Instruction & Operation Manual, Rev 1
Page
42
of 64
Setup & Tuning
Parameter Adjustment
Press LEAD LAG MASTER CONFIGURATION to adjust the following parameters.
Factory
Setting
Range /
Choices
Parameter and Description
Disabled
Enable
Disable
Master Enable/Disable
The Sequencer Master Enable/Disable is used to
“turn on” the Multiple Boiler Lead-
Lag Control.
WARNING:
Enable ONLY one Sequence Master in the boiler to boiler network.
Local
Local,
4-20mA,
Modbus
Lead Lag Setpoint Source (Central Heat page)
The setpoint may be based on local (customer entered value or outdoor reset) or
remote (4-20mA or Modbus) signals. Setpoint Source has the following selections:
Local
User entered CH Setpoint or Reset Curve provides the setpoint.
4-20mA
Input wired to J8 terminals 6 and 7 is used as setpoint.
Modbus
Modbus signal is used as setpoint.
STAT
terminal
STAT terminal,
Modbus STAT
LL Demand Switch (Central Heat page)
The Lead Lag Master
’s demand (Central Heat Enable/Disable) can be directly wired to the
Control or provide by the Modbus interface.
STAT terminal Lead Lag demand is present when a contact closure is received
between J8 terminals 1 and 3.
Modbus STAT Modbus signal provides demand.
Disable
Disable,
DHW Sensor
Shorted
LL DHW Demand Switch
Disable
DHW loop is disabled. Use this option with a single boiler-piped
DHW demand. See DHW Priority Method: Boost in the DHW
Configuration Menu.
DHW Sensor Shorted The Sequence Master responds to the DHW Call For Heat
when a switch is wired to the DHW sensor terminals. This allows one
or more boilers to provide heat to the IWH.
Disabled
Enable
Disable
DHW Two Boiler Start
The Sequencer to immediately start two boilers for a DHW call for heat. Used when
DHW is the largest demand. Only relevant when
“Primary Piped IWH” is selected.
3 Min
0.5 to 20 Min
Add Stage Detection Time
Slave boiler time delay after header temperature has dropped below the setpoint minus
“Difference below”. Longer time delay will prevent nuisance starts due to short
temperature swings.
1 Min
0.5 to 5 Min
Drop Stage Detection Time
Slave boiler time delay after header temperature has risen above the setpoint plus
“Difference Above” setpoint. Longer time delay will prevent nuisance stops due to
short temperature swings.
195 (ºF)
50 to 195 (ºF)
All Boilers Off Threshold
When this temperature is reached all Networked boilers are stopped at once without
any stop boiler time delays. This setpoint allows the Sequencer to respond to rapid
load increases.
40%
25 to 100 %
Base Load Common (Rate Allocation page)
To maximize condensing boiler efficiency, the firing rate is limited to an adjustable value.
Boilers are kept at or below this firing rate as long as the boilers can handle the load.
After last available boiler has started, the modulation rate limit is released up to
100%.
24 Hours
8 to 48 Hours
Lead Rotation Time (Algorithms page)
Time boilers will act as the lead before switching the lead to another boiler in the boiler to
boiler network.
