Control Systems Inc.
HBX MOD 0100 Modulating Module
Version 1.10
Control Systems Inc.
HBX MOD 0100 Modulating Module
Version 1.10
MOD-0100 M a n u a l P a g e 7
$!
Progressive modulation is a complex algorithm for
very precise control over modulating devices.
HBX Controls has optimized the process to work
effectively for multiple modulating boilers. This
modulation algorithm is a combination of series
and parallel modulation with additional benefits.
Underlying theory causes the first boiler to
modulate from the start percent (designated by
the installer within the modulating options in of
the Control) to 80% modulation. If the load still
requires more heat then boiler 1 decreases to 40%,
and boiler 2 increases from 0% to 40%
(maintaining 80% output with 2 modulating
boilers now on). As the load increases both
modulating boiler 1 and modulating boiler 2 will
increase to 80%. If there is still a higher load
requirement, both boiler 1 and boiler 2 will
decrease to 55% and modulating boiler 3 will
increase from 0% to 55%. All 3 modulating
boilers now take on approximately the same load
as the 2 modulating boilers at 80%. This process
will continue on until all boilers set up in the
system are firing. When all the modulating boilers
are firing and a load is still required, all 3 boilers
will modulate to 100% simultaneously.
As load decreases the modulating boilers will
simultaneously modulate down to the start
percent. The lag boiler will shut down and
remaining modulating boilers will increase their
modulating to split the remaining load in percent.
At this point to help with boiler cycling the
Control will allow the PID calculation to increase.
This will hold the lead boiler in the minimum fire
position for longer allowing the modulating boiler
to cycle less. As a result; system maintenance and
system wear due to boiler cycling is decreased.
BTU Output
Modulating Staging Types - Progressive
0%
100%
50%
25%
75%
Time Progression
B 2B 1 B 3 B 2B 1 B 3 B 2B 1 B 3 B 2B 1 B 3 B 2B 1 B 3 B 2B 1 B 3 B 2B 1 B 3
