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Siemens Building Technologies
Basic Documentation RVD110, RVD130
CE1P2381E
HVAC Products
11 Function block Space heating
27.05.2004
the attenuated outside temperature exceeds the heating limit.
The heating will be switched on again as soon as all 3 outside temperatures have
dropped below the heating limit by the amount of the switching differential.
The heating limit is determined as follows:
Heating limit = T
RwN
+ T
ECO
(nominal room temperature setpoint plus ECO tempera-
ture).
A nominal room temperature setpoint w
N
of +20 °C and an ECO temperature T
ECO
of
–5 K result in a heating limit of +15 °C.
11.6.5 Mode of operation of ECO function no. 2
ECO function no. 2 operates as an automatic 24-hour heating limit. The heating will be
switched off (mixing valve closed and heating circuit pump off) when the actual
or
the
composite outside temperature exceeds the heating limit.
The heating will be switched on again as soon as all 3 outside temperatures have
dropped below the heating limit by the amount of the switching differential.
The heating limit is determined as follows:
Heating limit = T
Rw akt
+ T
ECO
(current room temperature setpoint plus ECO temperature).
In contrast to ECO function no. 1, it is thus considered when reduced heating is used.
A current room temperature setpoint T
Rw akt
of +18 °C and an ECO temperature T
ECO
of
–5 K result in a heating limit of +13 °C.
In
standby
mode, the ECO function uses no setpoint, but a fixed value. Also, the heat-
ing limit has a minimum limitation, which cannot be lower than 2 °C.
The heating limit is determined as follows:
5 + T
ECO
(fixed value of 5 °C plus ECO temperature).
11.7 Quick setback
When changing from the nominal temperature to a lower temperature level (reduced
temperature or standby), the heating will be switched off, and it will remain off until the
room temperature has reached the respective setpoint of the lower temperature level.
Then, it will be switched on again to maintain the current setpoint.
When using no room temperature sensor or room unit, the controller maintains quick
setback during a defined period of time, which is dependent on
•
the composite outside temperature
•
an adjustable gain factor (operating line 63); when using setting 0, there will be no
quick setback when no room temperature sensor is present
When using a room temperature sensor or room unit, the setting on operating line 63 is
inactive.
11.8 Frost protection for the plant
Frost protection for the plant protects the heating plant against freeze-ups by activating
the heating pump (setting on operating line 73 = 1), provided both the controller and the
heat source are ready to operate (mains voltage present).
Frost protection for the plant is possible with or without outside sensor. The switching
differential is 1 K (fixed value).
Frost protection for the plant is always active, that is, also
•
when the control is switched off
•
during quick setback
•
during OFF by ECO
If required, frost protection for the plant can be deactivated (setting on operating
line 73 = 0).
Example
Example
