Formula To Calculate The Expansion Vessel Pre-Pressure; To Check The Water Volume And Flow Rate - Daikin CHYHBH05AA Installer's Reference Manual

▪ Domestic hot water tank – After installation. Immediately after
installation, the domestic hot water tank must be flushed with fresh
water. This procedure must be repeated at least once a day the
first 5 consecutive days after installation.
▪ Domestic hot water tank – Standstills. In cases where during
longer periods of time there is no consumption of hot water, the
equipment MUST be flushed with fresh water before usage.
▪ Domestic hot water tank – Disinfection. For the disinfection
function of the domestic hot water tank, see
control: advanced" on page 57.
▪ Domestic hot water tank – 3rd party tank installation. When
installing a 3rd party tank, take following requirements into
account:
▪ coil size should be ≥0.45 m
▪ water piping is ≥3/4" to avoid high pressure drops,
▪ a sensor pocket is foreseen at a correct place (above the
heating coil). The tank sensor should not be in contact with
water.
▪ maximum tank set point for a 3rd party tank is 60°C,
▪ in case of an electrical heater in the tank, make sure it is
installed correctly (above the heating coil).
Refer to the installation manual of the domestic hot water tank for
more information.
▪ Thermostatic mixing valves. In accordance with the applicable
legislation, it may be necessary to install thermostatic mixing
valves.
▪ Hygienic measures. The installation must be in compliance with
the applicable legislation and may require additional hygienic
installation measures.
▪ Recirculation pump. In
legislation, it may be required to connect a recirculation pump in
between the hot water end point and the recirculation connection
of the domestic hot water tank.
c
a b
d
a Recirculation connection
b Hot water connection
c Shower
d Recirculation pump
6.4.2 Formula to calculate the expansion vessel
pre-pressure
The pre-pressure (Pg) of the vessel depends on the installation
height difference (H):
Pg=0.3+(H/10) (bar)
6.4.3

To check the water volume and flow rate

The indoor unit has an expansion vessel of 10 litre with a factory set
pre-pressure of 1 bar.
To make sure that the unit operates properly:
▪ You must check the minimum and maximum water volume.
▪ You might need to adjust the pre-pressure of the expansion
vessel.
Minimum water volume
Check that the total water volume in the installation is minimum
13.5 litre, the internal water volume of the indoor unit NOT included.
CHYHBH05+08AA + EHYKOMB33A
Daikin hybrid for multi heat pump – heat pump module
4P471761-1A – 2017.10
"Domestic hot water
2
,
accordance with the applicable
INFORMATION
In critical processes, or in rooms with a high heat load,
extra water might be required.
NOTICE
When circulation in each space heating/cooling loop is
controlled by remotely controlled valves, it is important that
the minimum water volume is guaranteed, even if all of the
valves are closed.
a b d e
c f
T
a Outdoor unit
b Indoor unit
c Heat exchanger
d Boiler
e Bypass valve
f Pump
g Shut‑off valve (field supply)
h Collector
i Bypass valve (field supply)
RAD1...3 Radiator (field supply)
Maximum water volume
Use the following graph to determine the maximum water volume for
the calculated pre-pressure.
a
2.6
2.4
2.2
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.3
0 50 100 150 200
a Pre-pressure (bar)
b Maximum water volume (l)
Maximum leaving water temperature of 55°C for underfloor
heating applications
Maximum leaving water temperature of 80°C for radiator
applications
Example in case of an underfloor heating application: Maximum
water volume and expansion vessel pre-pressure in case of
55°C
6 Preparation
g h
95°C
RAD1 RAD2 RAD3
g i
250 300 350 400 450
Installer reference guide
b
19