Formula To Calculate The Expansion Vessel Pre-Pressure; To Check The Water Volume - Daikin ERHQ011BA Installer's Reference Manual

Cover the pipe end when inserting it through a wall, to
prevent dust and/or particles entering the pipe.
Use a decent thread sealant to seal connections.
For safety reasons, it is NOT allowed to add any kind of glycol to
the water circuit.
To avoid stagnation of water, it is important that the storage
capacity of the domestic hot water tank meets the daily
consumption of domestic hot water.
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.
The disinfection function provided on the equipment is specified
in the operation manual of the indoor unit.
It is recommended to avoid long runs of piping between the
domestic hot water tank and the hot water end point (shower,
bath,...) and to avoid dead ends.
The installation must be in compliance with the applicable
legislation and may require additional hygienic installation
measures.
In accordance with the applicable legislation, it may be
necessary to install thermostatic mixing valves.
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.
In accordance with the applicable 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
6.2.2 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)

6.2.3 To check the water volume

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
20 liter, the internal water volume of the indoor unit NOT included.
INFORMATION
In critical processes, or in rooms with a high heat load,
extra water might be required.
NOTICE
When circulation in each space heating 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.
EHBH/X16
Daikin Altherma - Low Temperature Split
4P313776-1 – 2012.05
a b c d f
T1
M1
e f
a Outdoor unit
b Indoor unit
c Heat exchanger
d Backup heater
e Pump
f Shut-off valve
g Collector (field supply)
h By-pass valve (field supply)
FHL1...3 Floor heating loop (field supply)
T1...3 Individual room thermostat (optional)
M1...3 Individual motorised valve to control loop FHL1...3 (field
supply)
Maximum water volume
Use the following graph to determine the maximum water volume for
the calculated pre-pressure.
a
2.5
2
1.5
1
0.5
0.3
0 20
50 100 150 200
a Pre-pressure (bar)
b Maximum water volume (l)
Example: Maximum water volume and expansion vessel pre-
pressure
Installation
height
(a)
difference ≤280 l
≤7 m No pre-pressure
adjustment is required.
>7 m Do the following:
Increase
pressure.
Check if the water
volume does NOT
exceed
maximum
water volume.
(a) This is the height difference (m) between the highest point of the
water circuit and the indoor unit. If the indoor unit is at the highest
point of the installation, the installation height is 0 m.
6 Preparation
g h
T2 T3
M2 M3
FHL1
FHL2
FHL3
250 300 350 400 450
Water volume
>280 l
Do the following:
Decrease the pre-
pressure.
Check if the water
volume does NOT
exceed
maximum
water volume.
The expansion vessel of
the indoor unit is too
the pre-
small for the installation.
the
allowed
Installer reference guide
b
the
allowed
20