Daikin EPRA10EAV3 Installer's Reference Manual page 220

10 | Configuration
Installer reference guide
220
▪ If Indirect (DHW + SH) is enabled: The boiler primarily covers or supports
domestic hot water heating (based on energy efficiency and operating
temperatures). Moreover, energy provided by the boiler is large enough to cover
the full building demand (F-07]=0), the switch-over between heat pump
operation and boiler operation for space heating is determined by the efficiency
calculation. If the boiler is intended solely for heat pump support ([F-07]=1),
primarily the heat pump is operation for space heating and the boiler is activated
to support in case of capacity shortage.
The switch-over between the heat pump system, parallel bivalent operation (if
applicable) 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]) or PE factor [7-03]
▪ [F-02] (only for [C-02]=2/3)
[C‑03], [C‑04], T , and T
calc
For space heating switch-over: Based on the settings above, the heat pump system
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 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
# Code
9.C.3 [C-03]
9.C.4 [C-04]
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 price)
boiler efficiency
lim
T
A
can never go below [C‑03] or above [C‑03]+[C‑04].
calc
Space heating by the heat
pump system...
Stops
Starts
Range: –25°C~25°C (step: 1°C)
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 heat
pump system and the auxiliary boiler.
(a)
× If:
▪ Electricity price: 20 c€/kWh
▪ Gas price: 6 c€/kWh
▪ Boiler efficiency: 0.9
Then: COP=(20/6)×0.9=3
Then...
Bivalent signal for the
auxiliary boiler is...
Active
Inactive
Description
Example
EPRA08~12EAV3+W1 + ETSH/X(B)12P30+50EF
Daikin Altherma 3 H MT ECH₂O
4P663478-1B – 2022.07