Bradford White Brute MagnaTech BMGV1600 Installation And Operation Instructions Manual page 71

Number of boilers Base load value
installed
1
2
3
4
5
6
7
8
Table 20. Base Load Settings
WARNING
If the Modbus addresses are not
assigned properly, the system could
fail to operate correctly, or it might
operate in an unsafe manner. This
could lead to property damage,
personal injury or death.
• When the Run sequence is initiated, the
unit with the least amount of runtime will
• If the heating demand increases so that
Value (see Table 20), the next unit in the
at 20 to 35% fan speed (depending on
down together, in reaction to the changes
in demand.
See Figure 41 and Figure 43
Control Settings for Lead Lag System - Part 1
1. Power up all of the units in the system.
2. In an installation with several units, you must give
each unit a different name, so that the controller of
the Lead unit can communicate with the other units.
All of the units come from the factory with a Modbus
these addresses. On each unit, go to the screen for
3. The unit operating as the Lead must be 'Master
other units should each be 'Slave Enabled' and have
unique Modbus address numbers typically 2 thru X
(total number of units)
NA
Low demand -
65%
The first boiler in
50%
sequence fires at
less than 65%
35%
35%
35% Demand increases -
Once the first boiler
35%
reaches 65%,
35%
the second boiler
switches on, and
both modulate
together between 20%
and 65% (this can be adjusted up to 20% and 85%).
Demand increases -
Once the first two
boilers reach 65%,
the third boiler
switches on, and all
boilers modulate together
between 20% and 65%. This continues as demand increases.
Nearing max. demand -
The last boiler becomes
active. Once all boilers
reach 65%, all are
allowed to go over
65%
Figure 43. Lead Lag Operation, 3 or more boilers
1 2 3
The Lead Lag controller will change the firing order of
the burners, based on the run time of each burner.
On the units, touch the controller Icon on the Home Screen.
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