Table of Contents
Advertisement
C
– DHW
ASCADE
The boiler cascade system has multiple options for priority and parallel DHW and heating.
The following levels of priority are configurable (and possible):
Priority level
0)
Switch Priority
1)
CH
2)
DHW
Table 14.2
Relevant variables
Specific parameters
DHW Priority
Both, CH or DHW priority, Parallel
DHW Max Priority Timer
Interval time for switching the priority
Table 14.3
C
– S
ASCADE
The managing boiler sends the calculated Cascade_Setpoint to the dependent boilers. The power of the boilers
is PID controlled based on the Calculated_Setpoint and T_Supply. Depending on the temperature difference
between T_System and Cascade_Setpoint (CH or DHW) the dependent boilers will start or stop using different
algorithms.
Quick Starting and Stopping Boilers
When there is a big difference between the T_System and the Cascade_Setpoint the call for a start or stop of the
next or last depending is done quicker.
C
– P
ASCADE
Several different power control modes can be selected to operate the cascade system.
•
Power mode 0:
Power control disabled; each boiler modulates based on the system setpoint.
•
Power mode 1:
Power control algorithm to have a minimum number of boilers active.
•
Power mode 2:
Power control algorithm to have a maximum number of boilers active.
•
Power mode 3:
Power control algorithm to have a balanced number of boilers active.
Cascade – Boiler rotation
The boiler rotation function can change the start/stop sequence for the cascade boilers.
The parameter Boiler_Rotation_Interval sets the number of days after which the sequence is updated. When
Boiler_Rotation_Interval is set to 0 boiler rotation is disabled.
When the parameter Burner_Rotation_Interval is updated the boiler rotation days left will be initialized to the new
Burner_Rotation_Interval setting.
When for example Burner_Rotation_Interval = 5 the start sequence is as following (x is the last boiler):
Days
Day 0-5
Day 5-10
Day 10-15
Day 15-20
Day 20-25
Table 14.4
122
PRIORITY
Description
When both CH and DHW demand have to be served, the priority is given to the DHW
demand for a given interval (indicated with parameter Minute_Switch_Priority).
As soon as the interval has expired the priority switches to CH demand.
The interval time will be reloaded and priority will switch again after the interval is over.
The priority is permanently given to CH Demand
The priority is permanently given to DHW Demand
Display
menu #
PB 42
PB 43
/
TART
STOP SEQUENCE
OWER BALANCE MODE
Start/Stop sequence
1-2-3-4-5..x
2-3-4-5..x-1
3-4-5..x-1-2
4-5..x-1-2-3
5..x-1-2-3-4
E93.1901EN032 Installation and Service Manual SlantFin VGH-CH / CO
Level
(Default)
Value
Installer
2
Installer
60 min.
Range
0, 1, 2
1..60 min.
Advertisement
Table of Contents
