6.2.
Modulation mode
Cascade controller operates the boiler to achieve selected boiler temperature. Only 1
st
boiler connected to 1
st
RS
output is active in the beginning of operation. When boiler reaches maximum power, counter starts to measure
time selected in Installer settings (v8) or Main Settings (v9) – Cascade - Waiting time. If set boiler temperature has
not been reached during this time period, second boiler will be activated and counter starts to measure “Waiting
time” again. This procedure is repeated until set boiler temperature (of boiler connected into the 1
st
RS output) is
reached or until all boilers are activated (Installer settings (v8) or Main settings (v9) – Cascade – Number of boilers).
When boiler temperature is reached (of boiler connected into the 1
st
RS output), boilers will be selectively
deactivated one by one if their summarized output power is lower than parameter: “Lower limit of effectivity”
(factory settings is 60%). This parameter is adjusted as follows:
Installer settings (v8) or Main settings (v9) – Cascade – Installer settings (v8) or Main settings (v9) – Cascade –
Lower limit of effectivity. Next boiler will be deactivated after 20min from time when boiler before was
deactivated. This process is repeated until:
CH boiler temperature (of the 1
st
boiler in 1
st
RS output) is lower than set CH temperature minus Hysteresis.
Or last boiler is in operation.
CS-503 cascade controller measures operation time of each boiler and selectively deactivates each boiler to
achieve equal operation during full heating season. So each boiler will work approximately the same time during
heating season interval.
7.
INSTALATION EXAMPLE
Eqithermal mode:
CH boiler1 temperature = 70°C
Temp of 2 boilers = 0°C
Temp of 1 boiler = 10°C
Hysteresis = 10°C
Modulation mode:
CH boiler1 temperature = 70°C
Waiting time = 20min
Hysteresis = 10°C
Eqithermal mode:
1
st
boiler will start at +10°C of outside temperature. 2
nd
boiler will be turned on when outside temperature
drops below 0°C of outside temp.
Modulation mode:
First boiler will be started accordingly CH boiler temp.
If the temperature is not reached during 20min of
operation, 2
nd
boiler will be started.
Boilers will stop at 70°C and 1
st
boiler starts when CH
temperature drops below Hysteresis.
Boiler
1
Boiler
2
431N +
weather
sensor