The application
A375.1
is very flexible. These are the basic
principles:
The applications A375.1 / A375.2 / A375.3 can ON / OFF control up
to 8 burner steps.
In application A375.1 the first 4 burner steps are controlled by
relays in the ECL 310. The next, max. 4 burner steps, are controlled
by relays in the extension module ECA 32 (placed in the base part
of the ECL 310).
Heating (circuit 1):
Typically, the common 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 common 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 first burner step is switched ON when the common boiler
temperature is lower than the desired boiler temperature. The
controller observes the common boiler temperature and switches
ON the next burner step if the common boiler temperature does
not increase satisfactorily. The switching OFF procedure of burner
steps is vice versa. A switching difference determines the ON / OFF
control.
The burners can be controlled in:
•
fixed sequence (example: Always 1-2-3-4-5) or
•
automatic rotating sequence (example: First period: 1-2-3-4-5,
second period: 2-3-4-5-1, third period: 3-4-5-1-2 and so on)
•
semi-automatic rotating sequence (example: First period: 1,
2-3-4-5, second period: 1, 3-4-5-2, third period: 1, 4-5-2-3 and
so on)
Furthermore, the boiler protection function will switch ON the
circulation pump when the boiler temperature gets above a
minimum value. 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 (S7 or 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 when the outdoor temperature is
higher than a set value.
The desired common boiler temperature can, via S10, be controlled
by means of an external voltage in the range 0-10 volt.
Typical A375.1 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
S3
Common boiler temperature sensor
S5
Return temperature sensor
S7
Room temperature sensor / ECA 30
(S10)
(External temperature control, not illustrated)
P1
Circulation pump
B1–B8 Burner 1 ... 8
A1
Alarm
The controller is pre-programmed with factory settings that are shown
in the relevant chapters of this guide.
Boiler sequence rotation / shift takes place at midnight.
12 | © Danfoss | 2017.09
VI.GU.L2.02
Operating Guide ECL Comfort 210/296/310, application A275/A375
