RBI HEATNET 3.0 Torus Series, Руководство пользователя

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SETUP & OPERATION
Page 12
Setup & Operation
Basic Multi Boiler System Operation
For boiler system setup/installations
please refer to the 2008 ASHRAE Handbook, CH12 or later
revision .
A basic multi boiler system typically uses boilers of the
same size and type. With HeatNet, this includes (1) Master
and (1-15) Member boilers. The boilers are connected using
an H-Net communications cable effectively creating (1)
boiler. This allows the system heating BTUs to be evenly
distributed amongst all boilers.
Basic multiple boiler system
A basic multi boiler system can be configured using the
boiler menus to create custom systems/features. These
features are best described in the section:
Default Settings
& Menu Item Description.
Along with these menu items
are hardware support for many auxiliary functions.
Once the system has been properly setup (all default menu
values used and H-Net addresses assigned), the system is
enabled by placing the REMOTE/LOCAL switch to the
LOCAL position on the Master boiler. All Member boilers
must have their respective switches in the REMOTE
position. When the Master boiler’s Heat Demand input
(LOCAL switch) closes, the system becomes operational
and will fire as many boilers as it needs to maintain the
header water temperature’s setpoint. See the DHW section
to fire using two setpoints.
When a boiler is to be fired in a multi boiler system (header
water temperature is below the heating band), the Master
checks the HeatNet boilers it has available. Then the Master
checks if a Lead Boiler is to be used (LEAD BOILER > 0).
The Master boiler then looks at which type of firing rotation
it has selected: LOFO, FOFO, TRUE (runtime), or MIXED.
In our example we will use the TRUE (runtime) rotation
since it is the default.
The Master now checks all of the runtimes to determine
which boiler has the least runtime based on the MIN
RUNTIME setting in SETTINGS: FIRING MODE: The
MIN RUNTIME setting is the minimum runtime interval in
hours that is used to compare boiler to boiler runtimes.
Once the boiler designated to fire has been determined, the
Master sends the command over the H-Net cable to fire that
boiler and resets the ADD BOILER delay timer to prepare
for the next boiler to fire. If the header water temperature is
still below the heating band and the ADD BOILER delay
timer has expired to zero, the process is repeated until the
header water temperature enters the heating band.
Runtime messages are displayed in the
lower left corner of the Home Screen . See Section
Messages for descriptions.
When a boiler receives a command to fire:
1. The system pump relay is enabled and the H-Net
control displays “Waiting for Flow” until the flow-
switch closes between J11A, 1 & 2 within the
programmed time (10 seconds default).
2. All elements in the interlock string, terminated between
J11A and J11B, must be closed before the sequence is
allowed to continue.
3. If all interlocks are closed, relay K5 is enabled to
command the combustion-air damper open (if used).
The H-Net control displays “Waiting for Damper to
Open” until the damper end switch closes.
4. Relay K6 is enabled energizing the local pump (if
used). The H-Net control commences its “Waiting for
Flow” timer (adjustable 10–240 sec.). When the flow
meets the minimum flow value for the boiler’s flow
meter (J1), and if used, the flow switch contact is
checked on terminals J11B, 5 &6.
With all the interlocks closed, the boiler start relay K1
is enabled. The H-Net control provides an output signal
to the blower, which sets the blower to the programmed
pre-purge speed. The Ametek blower uses a soft start
speed that is applied before the pre-purge speed.
“Waiting for Start Sequence” is displayed.