Boiler Plant Operation - Bosch Heatronic 4000 Installation & Operating Instructions Manual

Boiler Plant Operation

The Heatronic 4000 is able to operate up to four boilers to
maintain a boiler target temperature. Proportional, Integral &
Derivative (PID) logic is used in order to satisfy the boiler target
temperature for all plant configurations with the exception of
Dedicated Domestic Hot Water (DDHW). Proportional (P) logic
is used for DDHW. For proper operation of the boilers, the
Heatronic 4000 must be the only control that determines
when a boiler is to fire.
The boiler operator, or aquastat, remains in the burner circuit
& acts as a secondary upper limit on the boiler temperature.
The boiler aquastat temperature setting must be adjusted
above the Heatronic 4000's boiler maximum setting in order
to prevent short cycling of the burner.
Boiler Operation - --- --- --------------------- ----- ------- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Single Stage On⁄Off Boiler
Once a boiler is required to operate, the control turns on the
Stage 1 relay. Once the control turns on the Stage 1 relay, it will
display the "Boiler" icon & "100%" under the respective boiler
output status in the display.
Two Stage On⁄Off Boiler
Once a boiler is required to operate, the control turns on the
Stage 1 relay. Once the Fire Delay time plus the Stage Delay
time has expired, the control can turn on the Stage 2 relay if it
is required. Once the control turns on the Stage 1 relay, it will
display the "Boiler" icon & "50%" under the respective boiler
output status in the display. Once the control turns on the Stage
2 relay, it will display "100%".
Modulating Boiler
Once a boiler is required to operate, the control outputs an
analog signal corresponding to the Start Modulation setting
& then turns on the Stage 1 relay. Once the Fire Delay time
has expired, the modulating output is adjusted to the Minimum
Modulation setting. The control then holds the modulating output
at the Minimum Modulation until the Minimum Modulation Delay
time has elapsed. The control can then adjust the modulating
output from the Minimum Modulation as required. Once the
control turns on the Stage 1 relay, it will display the "Boiler"
under the respective boiler output status in the display. The
current firing rate is also displayed in the boiler output field.
EMS Boiler
Once a boiler is required to operate, the control outputs an
appropriate analog signal corresponding to the boiler target
temperature & then turns on the Stage 1 relay. Once the control
turns on the Stage 1 relay, it will display the "Boiler" under the
respective boiler output status in the display. The target water
temperature is also displayed in the boiler output field.
Boiler Target Temperature ------------ ------- ------------
The Boil TARG temperature is determined by the application
mode & the type of call received. The control displays the
temperature that it is currently trying to maintain at the boiler
supply sensor in the View menu. If the control does not presently
have a requirement for heat, it does not show a boiler target
temperature. Instead, "---" is displayed in the LCD.
Heatronic 4000
-------------------------------
Stage Delay -- --- --- --- --- - --- --- --- --- --- --- --- -- ---- --- -- --- --- --- --- --- --- --- --- --- --- -- -- --- --- ---
The STG DELAY is the minimum time delay between the firing
of each boiler or boiler stage. After this delay has expired the
control can fire the next boiler or boiler stage if it is required. This
setting can be adjusted manually or set to an automatic setting.
When the automatic setting is used, the control determines the
best stage delay based on the operation of the system.
Modulation Mode --- --- --- --- --- - --- --- --- --- --- --- --- - -- --- --- --- --- --- --- --- --- --- --- --- ---
When using multiple modulating boilers, a selection must be
made regarding the sequencing of the boilers. Two modulation
mode settings are provided considering condensing & non-
condensing boiler groups.
Modulation Mode is not available when the Application Mode
is configured for Dedicated Domestic Hot Water (DDHW).
• MOD COND (Modulation Mode - Modulating, Condensing
Boiler Group)
This setting is applicable for a group at least two modulating,
condensing boilers.
• MOD NC (Modulation Mode - Modulating, Non-Condensing
Boiler Group)
This setting is applicable for a group of at least two modulating,
non-condensing boilers.
Sequential Modulation (SEQ)
With Sequential Modulation, the control will turn on the fewest
boilers possible to meet the load. The control will bring a
boiler from its Minimum Modulation setting up to its Maximum
Modulation setting before bringing on another boiler. When
another boiler is turned on, the previous boiler will keep its
output at full fire.
100%
Parallel Modulation (PAR)
With Parallel Modulation, the control will turn on the most
boilers possible to meet the load. The control will bring on the
first boiler at Minimum Modulation and does not increase its
modulation. If more boiler output is required, the second boiler
will turn on at Minimum Modulation and does not increase its
modulation. Additional boilers are turned on at their Minimum
Modulation setting until all boilers are on. If still more boiler
output is required, all boilers are modulated up in parallel until
they reach their Maximum Modulation settings.
40%
Staging Mode Setup -- --- --- --- --- --- --- --- - --- --- -- -- --
When using multiple two-stage boilers, a selection must be
made regarding the staging order of the boilers. Two staging
modes are provided considering condensing & non-condensing
boiler groups.
8 of 60
60% Off Off
40% 40% 40%
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BTC461503101C | 6720810369 (2018/03)