Daikin Altherma EJHA04AAV3 Installer's Reference Manual page 67

The purpose of this function is to determine which heating source
can/will provide the space heating, either the outdoor unit or the
third-party gas boiler.
The switch-over between the outdoor unit and the gas boiler is
based on the following settings:
▪ [C‑03] and [C‑04]
▪ Electricity and gas prices ([7.4.5.1], [7.4.5.2], [7.4.5.3], and [7.4.6])
[C‑03], [C‑04], and T
calc
Based on the settings above, the outdoor unit calculates a value
T , which is variable between [C‑03] and [C‑03]+[C‑04].
calc
3°C
a
b
T [C-03]+[C-04]
[C-03]
calc
T
A
T Outdoor temperature
A
T Bivalent ON temperature (variable). Below this
calc
temperature, the gas boiler will always be ON. T
never go below [C‑03] or above [C‑03]+[C‑04].
3°C Fixed hysteresis to prevent too much switching between
outdoor unit and gas boiler
a Gas boiler active
b Gas boiler inactive
If the outdoor
temperature...
Space heating by
the outdoor unit...
Drops below T Stops
calc
Rises above T +3°C Starts
calc
INFORMATION
The bivalent signal for the third-party gas boiler is located
on X2M/7+8 of the outdoor unit. When it is activated,
contact X2M/7+8 is closed. When it is deactivated,
X2M/7+8 is open.
See also "To connect the bivalent signal for third-party gas
boiler" on page 46.
# Code
N/A [C-03] Range: –25°C~25°C (step: 1°C)
N/A [C-04] Range: 2°C~10°C (step: 1°C)
The higher the value of [C‑04], the higher
the accuracy of the switch-over between
the outdoor unit and the gas boiler.
To determine the value of [C‑03], proceed as follows:
1 Determine the COP (= coefficient of performance) using the
formula:
Formula
COP = (Electricity price / gas
(a)
price) × boiler efficiency
(a) Make sure to use the same units of measurement for the
electricity price and gas price (example: both c€/kWh).
2 Determine the value of [C‑03] using the graph:
EJHA04AAV3 + EHY2KOMB28+32AA
Daikin Altherma Hybrid hydrosplit heat pump
4P531180-1 – 2018.06
can
calc
Then...
Bivalent signal for
the gas boiler is...
Active
Inactive
Description
Example
If:
▪ Electricity price: 20 c€/kWh
▪ Gas price: 6 c€/kWh
▪ Boiler efficiency: 0.9
Then: COP = (20/6)×0.9 = 3
COP
6
5
4
3
2
1
0
-14 -12 -10 -8 -6 -4 -2
Example:
a [C‑03]=2.5 in case of COP=3 and LWT=35°C
b [C‑03]=10.5 in case of COP=3 and LWT=55°C
NOTICE
Make sure to set the value of [5‑01] at least 1°C higher
than the value of [C‑03].
Electricity and gas prices
INFORMATION
To set electricity and gas price values, do NOT use
overview settings. Set them in the menu structure instead
([7.4.5.1], [7.4.5.2], [7.4.5.3], and [7.4.6]). For more
information on how to set the energy prices, see the
operation manual and the user reference guide.
INFORMATION
Solar panels. If solar panels are used, set the electricity
price value very low to promote the use of the heat pump.
# Code
[7.4.5.1] N/A What is the high electricity
price?
[7.4.5.2] N/A What is the medium electricity
price?
[7.4.5.3] N/A What is the low electricity
price?
[7.4.6] N/A What is the fuel price?
Bottom plate heater
Applies only when the option bottom plate heater kit is installed.
▪ [F-02] Bottom plate heater ON temperature: defines the outdoor
temperature below which the bottom plate heater will be activated
by the outdoor unit in order to prevent ice build-up in its bottom
plate at lower outdoor temperatures.
▪ [F-03] Bottom plate heater hysteresis: defines the temperature
difference between bottom plate heater ON temperature and the
bottom plate heater OFF temperature.
Bottom plate heater
a
[F-03]
b
T
A
[F-02]
T Outdoor temperature
A
a On
b OFF
# Code
N/A [F-02] Bottom plate heater ON temperature:
3°C~10°C
N/A [F-03] Hysteresis: 2°C~5°C
10 Configuration
0 2 4 6 8 10 12 14
2.5 (a)
10.5 (b)
Description
Description
Installer reference guide
67