5 Application guidelines
Installer reference guide
18
ERLQ004~008CA + 26CB6W
Daikin Altherma – Low temperature split
4P449978-1B – 2018.07
B
TI
Boiler thermostat input
A
Auxiliary contact (normal closed)
H
Heating demand room thermostat (optional)
K1A
Auxiliary relay for activation of indoor unit (field supply)
K2A
Auxiliary relay for activation of boiler (field supply)
Indoor
Indoor unit
Auto
Automatic
Boiler
Boiler
NOTICE
▪ Make sure the auxiliary contact has enough differential
or time delay to prevent frequent changeover between
indoor unit and auxiliary boiler.
▪ If the auxiliary contact is an outdoor temperature
thermostat, install the thermostat in the shadow so that
it is NOT influenced or turned ON/OFF by direct
sunlight.
▪ Frequent changeover may cause corrosion of the
auxiliary boiler. Contact the manufacturer of the
auxiliary boiler for more information.
5.4
Setting up the domestic hot water
tank
The DHW tank is integrated in the indoor unit, and contains a 2.4 kW
booster heater. The booster heater contains 2 safeties: a thermal
cut-out and a thermal fuse. If a certain temperature is exceeded, the
safeties deactivate the booster heater.
INFORMATION
The non-self-resetting thermal cut-out of the booster heater
is set below 89°C.
5.4.1
System layout – Integrated DHW tank
FHL1
FHL2
FHL3
M
UI
a
b c d
h
h
i
f
e
g
j
a
Outdoor unit
b
Indoor unit
c
Heat exchanger
d
Backup heater
e
Pump
f
Motorised 3‑way valve
g
DHW tank
h
Shut-off valve
i
Collector (field supply)
j
Booster heater
FHL1...3
Under floor heating
UI
User interface
5.4.2
Selecting the volume and desired
temperature for the DHW tank
People experience water as hot when its temperature is 40°C.
Therefore, the DHW consumption is always expressed as equivalent
hot water volume at 40°C. However, you can set the DHW tank
temperature at a higher temperature (example: 53°C), which is then
mixed with cold water (example: 15°C).
Selecting the volume and desired temperature for the DHW tank
consists of:
1
Determining the DHW consumption (equivalent hot water
volume at 40°C).
2
Determining the volume and desired temperature for the DHW
tank.
Determining the DHW consumption
Answer the following questions and calculate the DHW consumption
(equivalent hot water volume at 40°C) using typical water volumes:
Question
Typical water volume
How many showers are needed
per day?
1 shower = 10 min×10 l/min =
100 l
How many baths are needed per
day?
1 bath = 150 l
How much water is needed at the
kitchen sink per day?
1 sink = 2 min×5 l/min = 10 l
Are there any other domestic hot
water needs?
—
Example:
If the DHW consumption of a family (4 persons) per day
is as follows:
▪ 3 showers
▪ 1 bath
▪ 3 sink volumes
Then the DHW consumption = (3×100 l)+(1×150 l)+(3×10 l)=480 l
Determining the volume and desired temperature for the DHW
tank
Formula
Example
V
1
=V
2
+V
2
×(T
2
−40)/(40−T
1
)
If:
▪ V
2
=180 l
▪ T
2
=54°C
▪ T
1
=15°C
Then V
1
=280 l
V
2
=V
1
×(40−T
1
)/(T
2
−T
1
)
If:
▪ V
1
=480 l
▪ T
2
=54°C
▪ T
1
=15°C
Then V
2
=307 l
V
1
DHW consumption (equivalent hot water volume at 40°C)
V
2
Required DHW tank volume if only heated once
T
2
DHW tank temperature
T
1
Cold water temperature
Possible DHW tank volumes
Type
Possible volumes
Integrated DHW tank
▪ 180 l
▪ 260 l
Energy saving tips
▪ If the DHW consumption differs from day to day, you can program
a weekly schedule with different desired DHW tank temperatures
for each day.
▪ The lower the desired DHW tank temperature, the more cost
effective. By selecting a larger DHW tank, you can lower the
desired DHW tank temperature.
▪ The heat pump itself can produce domestic hot water of maximum
55°C (50°C if outdoor temperature is low). The electrical
resistance integrated in the DHW tank (booster heater) can