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2 = Cascade
4 = BMS
6 = Thermostat
Cascade:
The boiler is part of a group of boilers sequenced together. The designated Master boiler determines the
total output needed from the group based on the set point and controlling sensor reading. It assigns portions of this
output to itself (Master) and the Member boilers. When Cascade is selected, each boiler in the group requires a
unique address (see below).
BMS (Building Management System):
The control modulates the boiler based on the 0 - 10 VDC signal delivered
to the appropriate terminals on the connection board. When BMS is selected additional parameters for BMS
operation may need to be adjusted. These can only be accessed using optional PC interface software.
Thermostat:
The control modulates the boiler based on the user set point and the temperature of the temperature of
the selected controlling sensor.
The default control is Thermostat.
16.7.3
CASCADE ADDRESS
The boiler designated as the Master needs to be programmed with address 0. All the Member boilers require
addresses from 1 to 7, and the addresses must be different for each Member. The addresses can be in any order,
regardless of the order in which the units are wired together. This parameter is adjustable by pressing the
Up
or
Down
buttons and then pressing the
Enter/Reset
button to store the assigned address. The outdoor air (if used) and
system supply sensor must be connected to the Master boiler. The default address is 1.
16.7.4
MAXIMUM CASCADE SETPOINT
This parameter determines the set point used by the individual boilers in a Cascade. When a boiler is commanded to
fire by the Master boiler, it will attempt to achieve this temperature at its outlet. The Master boiler will limit the
modulation of the last boiler to fire in order to hold the temperature at the system supply sensor to the user set point.
If any of the boiler outlet temperatures reach the maximum cascade setpoint, the boiler will then modulate down on its
own in order to keep its outlet temperature within the maximum cascade setpoint. Therefore, this parameter can be
used to limit the outlet temperatures of all the boilers in a Cascade.
Note
: This parameter does not apply when the boiler is heating an indirect DHW tank.
The
maximum
cascade setpoint temperature can be adjusted in ½
increments using the
Up
or
Down
buttons and
the desired value stored by pressing the
Enter/Reset
button. The temperature range of this parameter is 0
C to
100
C. The default value is 85
C.
16.7.5
CASCADE OFFSET
This parameter determines how much the temperature must go above the setpoint before the lead boiler switches off.
The cascade offset temperature can be adjusted in ½
increments using the
Up
or
Down
buttons and the desired
value stored by pressing the
Enter/Reset
button. The temperature range of this parameter is 0
C to 40
C. The
default value is 5.5
C.
16.7.6
CASCADE OFF-ON DIFFERENTIAL
This parameter determines how much the temperature must drop below the turn off temperature (se offset)
before the master boiler re-enables the cascade.
The cascade differential temperature can be adjusted in ½
increments using the
Up
or
Down
buttons and the
desired value stored by pressing the
Enter/Reset
button. The temperature range of this parameter is 0
C to 40
C.
The default value is 11
C.
