The application
A275.3
is very flexible. These are the basic
principles:
Heating (circuit 1):
Typically, the boiler temperature is adjusted according to your
requirements. The boiler temperature sensor S3 is the most
important sensor. It must be placed correctly in order to measure
the boiler temperature. The desired boiler temperature at S3 is
calculated in the ECL controller, based on the outdoor temperature
(S1). The lower the outdoor temperature, the higher the desired
boiler temperature. The boiler temperature is also the flow
temperature in the direct connected heating circuit.
By means of a week schedule (up to 3 ‘Comfort’ periods / day), the
heating circuit can be in ‘Comfort’ or ‘Saving’ mode (two different
temperature values for the desired room temperature). In 'Saving'
mode a 'Total stop' function can be selected in order to switch OFF
the heating.
The burner is switched ON when the boiler temperature is
lower than the desired boiler temperature and switched OFF
when the boiler temperature is higher than the desired boiler
temperature. A switching difference determines the ON / OFF
control. Furthermore, the boiler protection function will only
switch ON the circulation pump if the boiler temperature gets
above a minimum temperature. A minimum ON-time can be set for
the burner in order to increase the boiler's efficiency.
The return temperature (S5) to the boiler should not be too
high (condensing boiler) or too low (oil or gas fired boiler). If so,
the desired boiler temperature can be decreased or increased.
Furthermore, the return temperature limitation can be dependent
of the outdoor temperature. Typically, the lower the outdoor
temperature, the higher the accepted return temperature.
If the measured room temperature (measured by S7 or the remote
control unit ECA 30) does not equal the desired room temperature,
the desired boiler temperature can be adjusted.
The circulation pump (P1) is ON at heat demand or at frost
protection.
The heating can be switched OFF if the outdoor temperature gets
higher than a set value.
Typical A275.3 application:
* Pressure relief valve
The shown diagram is a fundamental and simplified example and does
not contain all components that are necessary in a system.
All named components are connected to the ECL Comfort controller.
List of components:
S1
Outdoor temperature sensor
S2
Return temperature sensor, circuit 2
S3
Boiler temperature sensor, circuit 1
S4
Flow temperature sensor, circuit 2
S5
Return temperature sensor, circuit 1
S6
DHW tank temperature sensor
S7
Room temperature sensor / ECA 30, circuit 1
S8
Room temperature sensor / ECA 30, circuit 2
M2
Motorized control valve, circuit 2
P1
Circulation pump, circuit 1
B1
Burner
P3
DHW heating pump, circuit 3
P4
Circulation pump, circuit 2
The controller is pre-programmed with factory settings that are shown
in the relevant chapters of this guide.
8 | © Danfoss | 2017.09
VI.GU.L2.02
Operating Guide ECL Comfort 210/296/310, application A275/A375