Burnham K2WT Residential, Инструкция по установке, эксплуатации и обслуживанию

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XII. Operation
(continued)
5. Customized Sequences
Normally, boilers are started and stopped in
numerical order. However, custom sequences
may be established to optimize the heat delivery.
For example, in order to minimize boiler cycling,
a large boiler may be selected to run first during
winter months and then selected to run last for
the remainder of the year.
6. Multiple Demands
The Sequence Master responds to Central Heat,
Auxiliary Heat, DHW and frost protection demands
similar to the stand alone boiler. For example,
when selected and DHW priority is active, the
sequence master uses DHW setpoint, “Diff
Above”, “Diff Below” and pump settings.
7. Shared or Isolated DHW Demand
When the Indirect Water Heater (IWH) parameter
is set to “Primary Piped” the Sequence Master
sequences all required boilers to satisfy the DHW
setpoint. When “Boiler Piped” is selected only
the individual slave boiler, with the wired DHW
demand and pump, fires to satisfy the DHW
setpoint.
8. DHW Two boiler Start
When the Indirect Water Heater (IWH) parameter
is set to “Primary Piped” and the DHW Two Boiler
Start parameter is set to “Enabled” two boilers
are started without delay in response to a DHW
call for heat. This feature allows rapid recovery
of large IWH’s and multiple IWH’s.
9. Optimized Boiler Modulation
Boiler firing rate is managed to increase smoothly
as boilers are started. For example, when a
second boiler is started the initial firing rate is
100%/2 or 50%, when the third boiler is started
the firing rate starts at 200%/3 or 66%. After the
initial start, the Sequence Master develops a
unison firing rate demand based on it’s setpoint
and sensed header temperature.
10. Innovative Condensing Boiler Control
During low loads, the Sequence Master limits firing
rates to a “Base Load Common Rate” to ensure
modulating condensing boiler peak operating
efficiency. Lower firing rates boost efficiency by
helping increase the amount of flue gas water
vapor condensation. The Control maintains a
“Base Load Common Rate” until the last lag boiler
is started. At this point, the “Base Load Common
Rate” is released to allow boilers to modulated
as required to meet heat load.
11. Advanced Boiler Sequencing
After there is a Call For Heat input, both header
water temperature and boiler firing rate percent
are used to start and stop the networked boilers.
The control starts and stops boilers when the
water temperature is outside the user selected
“Diff Above” and “Diff Below” settings. Also, in
order to minimize temperature deviations, the
control adjusts the number of boilers running
based on the firing rate. This combination allows
the boilers to anticipate slow load changes before
they disrupt water temperature yet still respond
quickly to sudden load changes. These special
sequencer features help reduce energy wasting
system temperature swings and the resulting
unnecessary boiler cycling.
12. Stop All Boilers
All boilers are stopped without delay if the Call for
Heat input is removed or if the header temperature
is higher than 195°F (90.6°C) (field adjustable).