Daikin EPRA16DAV3 Installer's Reference Manual page 191

Bivalent
EPRA14~18DAV3+W1 + ETBH/X16DF6V+9W
Daikin Altherma 3 H HT W
4P587501-1B – 2020.10
Bivalent
Only applicable in case of auxiliary boiler.
About bivalent
The purpose of this function is to determine which heating source can/will provide
the space heating, either the heat pump system or the auxiliary boiler.
# Code
[9.C.1] [C-02]
▪ If Bivalent is enabled: When the outdoor temperature drops below the
bivalent ON temperature (fixed or variable based on energy prices), the space
heating by the indoor unit stops automatically and the permission signal for the
auxiliary boiler is active.
▪ If Bivalent is disabled: Space heating is only done by the indoor unit within the
operation range. The permission signal for the auxiliary boiler is always inactive.
The switch-over between the heat pump system and the auxiliary boiler is based
on the following settings:
▪ [C‑03] and [C‑04]
▪ Electricity and gas prices ([7.5.1], [7.5.2], [7.5.3], and [7.6])
[C‑03], [C‑04], and T
calc
Based on the settings above, the heat pump system calculates a value T
variable between [C‑03] and [C‑03]+[C‑04].
3°C
a
b
T [C-03]+[C-04]
[C-03]
calc
T Outdoor temperature
A
T Bivalent ON temperature (variable). Below this temperature, the auxiliary boiler will
calc
always be ON. T
3°C Fixed hysteresis to prevent too much switching between heat pump system and
auxiliary boiler
a Auxiliary boiler active
b Auxiliary boiler inactive
If the outdoor
temperature...
Drops below T
calc
Rises above T +3°C
calc
Bivalent: Indicates if the space heating is also
performed by means of another heat source than
the system.
▪ 0 No: Not installed
▪ 1 Yes: Installed. The auxiliary boiler (gas boiler,
oil burner) will operate when the outdoor
ambient temperature is low. During bivalent
operation, the heat pump is turned off. Set this
value in case an auxiliary boiler is used.
T
A
can never go below [C‑03] or above [C‑03]+[C‑04].
calc
Space heating by the heat
pump system...
Stops
Starts
9 Configuration
|
Description
, which is
calc
Then...
Bivalent signal for the
auxiliary boiler is...
Active
Inactive
Installer reference guide
191