Bosch Buderus SSB255, Руководство по управляющим операциям

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2 2 | Bosch Buderus SSB255 | SSB399 | SSB512 Boilers Control Operations Guide
03.2018
|
Bosch Thermotechnology Corp. Data subject to change
7.3 Cascade - start sequence
1. When the system temperature is less than Target Setpoint minus the value
of CH Hysteresis (par. #7) the lead boiler in the cascade will start.
Cascade
Parameter
Description
Default
Value
Range
7 CH Hysteresis 5.4°F 0-36°F
Table 15
The control will establish an initial Calculated Setpoint based upon the
diff erence between the Target Setpoint and the measured system
temperature. The larger the deviation between these two values will result
in a larger response. This response will be linearly scaled between the
values of
Max Setpoint Offset Down
(par.# 79) and
Max Setpoint Offset
Up
(par.#80). The boiler will remeasure the diff erence between the Target
Setpoint and the measured system temperature once a period of time
equal to [
Delay Period Start Next Boiler
(par.#75) x
Start Modulation
Delay Factor
(par.#81)] has passed. After this period of time has
passed a new calculated setpoint will be targeted based upon the current
conditions.
Cascade
Parameter
Description
Default
Value
Range
75 Delay Period Start Next Boiler 15 sec. 5 – 300 sec.
77 Diff erential Down Start Boiler 9°F 0 - 36°F
79 Max Setpoint Off set Down 7.2 0 - 36°F
80 Max Setpoint Off set Up 18°F 0 - 36°F
81 Start Mod Delay Factor 5 0 - 60
Table 16
2. The Managing boiler must wait to bring on the next boiler until a period of
time equal to
Delay Period Start Next Boiler
(par.#75) has past. After
this period of time has past the Managing boiler checks the power % of
all boilers which are burning and if the system temperature is below the
desired setpoint and the % power of the operating boilers is greater than
the value of
Next Boiler Start Rate
(par.#82) then the next boiler in the
cascade sequence is started. If system temperature is below
Hyst Down
Start Boiler
(par.#77) then
Delay Period Start Next Boiler
(par.#75) will
be ignored.
Cascade
Parameter
Description
Default
Value
Range
75 Delay Period Start Next Boiler 15 sec. 5 – 300 sec.
82 Next Boiler Start Rate 80% 10 – 100%
Table 17
This sequence of bringing on additional boilers within the cascade will be repeated.
7.4 Cascade - stop sequence
1. When the power (%) level of one boiler falls below the value of
Next Boiler
Stop Rate
(par.#83) the last boiler brought on will be stopped. A delay
period follows before any other boilers are stopped. This delay is equal to
Delay Period Stop Next Dependent
(par.#76)
Cascade
Parameter
Description
Default
Value
Range
76 Delay Period Stop Next Boiler 15 sec. 5 – 300 sec.
78 Hyst Up Stop Boiler 3.6°F 0 - 36°F
83 Next Boiler Stop Rate 30% 10 – 100%
Table 18
After the Delay Period, if the power (%) level of one boiler falls below the
value of
Next Boiler Stop Rate
then another boiler is stopped and the Delay
Period begins again. If system temperature is above
Hyst Up Stop Boiler
(par.#78) then
Delay Period Stop Next Boiler
(par.#76) will be ignored.