HydroTherm HeatNet KN -6 User Information page 68

DEFAULT SETTINGS & MENU ITEM DESCRIPTIONS
MODULATE DELAY
TIME
MOD MAX – LAST FIRE
MOD MODE
DROP DOWN
DELAY RELEASE
(0 – 60min)
10 secs
(25 – 100%)
70%
ADAPTIVE
ON CALL
0s
boiler. A boiler is stopped immediately when the top of the heat
band is exceeded. If a second boiler needs to stop, the
SHEDBOILER DELAY will need to expire before stopping.
This is the time the boiler remains in min-fire before it relinquishes
control to the modulation % signal.
This value represents the maximum % of input on the boilers if all
the available boilers are not firing. Once all boilers are firing, this
clamp is removed and all boilers are allowed to modulate up to
100%. When this value is limiting the input an ‗*' is displayed and
the ―INPUT CLAMP‖ message is displayed in the STATUS screen.
This value is derived by: multiplying twice the minimum fire rate of
the boiler with the least turndown (2* turndown(20% 5:1, 25% 4:1,
33% 3:1)).
In mixed boiler size configurations, more than (2) boilers in a
system, or when ―bumps‖ in the temperature occur as boilers are
added and subtracted, this value may need adjustment. The
adjustments will help produce smooth temperature control when
each boiler is started and stopped. This method ensures that, once a
new boiler starts to fire, and holds its fire rate at the minimum
setting, it does not add its BTU output to a boiler already firing at
100%. The boilers can not be fired starting @ 0%, but start at a
minimum (example: 20%) and introduce a minimum amount of
BTUs into the system. Section: SETUP & OPERATION
The MOD MAX value is also applied when using the AA
terminal for High Fire and when using the 4-20 mA input for
direct modulation. When these demands for heat are used,
the maximum modulation the boiler can obtain when first
starting is equal to the; ADVANCED SETUP: MODULAR
BOILER SET: MOD MAX – LAST FIRE:. The timer value
ADVANCED SETUP: MODULAR BOILER SET:ADD BOILER
DELAY is used in conjunction to limit the modulation for this
amount of time. Once the boiler has fired and the ADD
BOILER DELAY time expires, the full modulation is available.
This change is a protective means for extending the life of the
heat exchanger which may consistently be exposed to thermal
ADAPTIVE MOD
If MODULATION MODE is set to ADAPTIVE on the Master
boiler, the Master lowers the system modulation rate of all currently
running boilers before a newly started boiler enters the Main Valve
state. Upon entering the Main Valve state of a newly fired boiler,
the Master waits the DELAY RELEASE time before allowing the
PID to resume modulation control. With MOD MODE set to ORIG
KN, The Master boiler keeps firing at the current modulation rate
when a new boiler is added and lets the PID adjust modulation rate
accordingly.
If drop down is set to ON PILOT and MOD MODE = ADAPTIVE,
and when a newly added boiler starts, the system waits until it enters
its PILOT state before bring the system modulation down. This
allows for the system to prepare for the new energy that is to be
introduced. If DROP DOWN is set to immediately, the system
modulation is lowered as soon as the newly added boiler is called.
Once the Main Valve opens on the newly added boiler and the MOD
MODE = ADAPTIVE the Master waits this amount of time before
releasing the PID to control modulation. This allows for the newly
added boiler to accumulate some soak time.
This is a global delay controlled by the Master boiler. It is
comparable to the MODULATE DELAY setting, but this is a local
setting on each boiler.
HeatNet Control V3 2.x
stress.
Page 68