Formula To Calculate The Expansion Vessel Pre-Pressure - Daikin Altherma Installer's Reference Manual

6 Preparation
▪ Provide drain taps at all low points of the system in order to allow
complete drainage of the water circuit.
▪ Provide a proper drain for the pressure relief valve to avoid water
coming into contact with electrical parts.
▪ Provide air vents at all high points of the system, which must also
be easily accessible for servicing. An automatic air purge is
provided in the indoor unit. Check that the air purge is NOT
tightened too much, so that automatic release of air in the water
circuit is possible.
▪ Only use materials that are compatible with water used in the
system and with the materials used in the indoor unit.
▪ Check that all components in the field piping can withstand the
water pressure and water temperature.
▪ When using non-brass metallic piping, insulate the brass and non-
brass properly so that they do NOT make contact with each other.
This to prevent galvanic corrosion.
▪ Never use Zn-coated parts in the water circuit. Because the unit's
internal water circuit uses copper piping, excessive corrosion may
occur.
▪ Only use appropriate tooling to handle brass, which is a soft
material. If NOT, pipes will get damaged.
▪ Select the water piping diameter in relation to the required water
flow and the available external static pressure of the pump. See
"15 Technical data" on page 76 for the external static pressure
curves of the indoor unit.
▪ You can find the minimum required water flow for the indoor unit
operation in the following table. When the water flow is lower, flow
error 7H will be displayed and the indoor unit will be stopped.
Model
04
08+16
▪ When using a 3-way valve in the water circuit make sure that the
domestic hot water circuit and the floor heating circuit is fully
separated.
▪ When using a 2-way valve or a 3-way valve in the water circuit,
the maximum change-over time of the valve must be 60 seconds.
▪ It is strongly recommended to install an additional filter on the
heating water circuit. Especially to remove metallic particles from
the filed heating piping, it is advised to use a magnetic or cyclone
filter, which can remove small particles. Small particles may
damage the unit and will NOT be removed by the standard filter of
the heat pump system.
▪ If air, moisture or dust gets into the water circuit, problems may
occur. To prevent this:
▪ Only use clean pipes
▪ Hold the pipe end downwards when removing burrs.
▪ 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.
Installer reference guide
24
Minimum water flow (l/min)
5
11
▪ 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
6.3.2 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)
6.3.3 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
10 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.
a b c d f
T1
M1
e f
FHL1
a Outdoor unit
b Indoor unit
c Heat exchanger
d Backup heater
e Pump
g h
T2 T3
M2 M3
FHL2
FHL3
ERLQ004~008CAV3 + EHBH/X04+08CA
Daikin Altherma - Low Temperature Split
4P313774-1C – 2012.11