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XII. Operation
F. Changing Adjustable Parameters (continued)
“Press”
button to access the following parameters:
Factory
Setting
Range / Choices
Parameter and Description
Disable
Enable,
Disable
Master Enable/Disable
The Sequencer Master Enable/Disable is used to “turn on” the Multiple Boiler Controller.
Warning! enable ONLY one Sequence Master.
Boiler
Piped
Boiler Piped,
Primary Piped
Indirect Water Heater (IWH
)
Boiler Piped
Sequencer to respond to an Isolated DHW demand that is piped to a single
boiler. The individual boiler goes on “Leave” from the Sequencer Master and
goes to DHW Service.
Primary Piped The Sequence Master responds to the DHW Call For Heat. 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 visible when primary piped IWH is selected.
180 Secs 120 - 1200 Secs
Boiler Start Delay
Slave boiler time delay after header temperature has dropped below the setpoint minus “Diff
below” setpoint. Longer time delay will prevent nuisance starts due to short temperature swings.
195°F
(90.6°C)
Central Heat
Setpoint,
195°F (90.6°C)
Stop All Boilers Setpoint
When this temperature is reached all boilers are stopped. This setpoint allows the Sequencer to
respond to rapid load increases.
70%
50% - 100%
Base Load Common Rate
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%.
3
1-5
Response Speed
This parameter adjusts the Sequence Master temperature controller Proportion Integral Derivative
(PID) values. Higher values cause a larger firing rate change for each degree of temperature
change. If set too high firing rate “overshoots” required value, increases to high fire causing the
temperature to exceed the “Diff Above” setpoint and cycle the boiler unnecessarily. Lower values
cause a smaller firing rate change for each degree of temperature change. If set too low, the firing
rate response will be sluggish and temperature will wander away from setpoint.
“Press”
button to access the following parameters:
Factory
Setting
Range / Choices Parameter and Description
None
1-8
Boiler Address
Each boiler must be given a unique address. When
“
Normal” slave selection order is used, the
boiler address is used by the Master Sequencer as the boiler start order. The boiler address is
also the Modbus Address when a Energy Management System is connected.
Normal
Use Boiler First,
Normal,
Use Boiler Last
Slave Selection Order
“Use Boiler First”; places the Slave in the lead permanently.
“
Normal”; firing order follows boiler number (1,2,3,..) order.
“Use Boiler Last”; places the slave last in the firing order.
