Setting The Pre-Pressure Of The Expansion Vessel; Connecting The Water Circuit - Daikin EKHBRD-AY1 Installation Manual

3 Using the table and instructions below, determine if the total
water volume in the installation is below the maximum allowed
water volume.
Installation
65°C ≤270 l
height
80°C ≤180 l
(a)
difference
No pre-pressure adjustment
≤7 m
required.
Actions required:
• pre-pressure must be
increased, calculate
according to
the pre-pressure of the
>7 m
expansion vessel"
• check if the water volume
is lower than maximum
allowed water volume
(use graph below)
(a) Installation height difference: height difference (m) between the highest
point of the water circuit and the indoor unit. If the indoor unit is located at
the highest point of the installation, the installation height is considered 0 m.
Calculating the pre-pressure of the expansion vessel
The pre-pressure (Pg) to be set depends on the maximum
installation height difference (H) and is calculated as below:
Pg=(H/10+0.3) bar
Checking the maximum allowed water volume
To determine the maximum allowed water volume in the entire circuit,
proceed as follows:
1 Determine for the
corresponding maximum water volume using the graph below.
2 Check that the total water volume in the entire water circuit is
lower than this value.
If this is not the case, the expansion vessel inside the indoor unit is
too small for the installation.
2.5
2
1.5
1
0.5
0.3
0.0
0 20 50 100 150
maximum water volume [l]
= pre-pressure
= maximum water volume
= increase pre-pressure vessel volume
= decrease pre-pressure vessel volume
Example 1
The indoor unit is installed 5 m below the highest point in the water
circuit. The total water volume in the water circuit is 100 l.
In this example, no action or adjustment is required.
Example 2
The indoor unit is installed at the highest point in the water circuit.
The total water volume in the water circuit is 380 l.
EKHBRD011~016AAV1+Y1
Indoor unit for air to water heat pump system
4PW54465-1C
Water volume
65°C >270 l
80°C >180 l
Actions required:
• pre-pressure must be
decreased, calculate
according to "Calculating
the pre-pressure of the
expansion vessel"
• check if the water volume
is lower than maximum
allowed water volume
(use graph below)
"Calculating
Expansion vessel of the unit
too small for the installation.
calculated pre-pressure (Pg)
200 250 300 350 400
Result:
Since 380 l is higher than 180 l or 270 l, the pre-pressure must
be decreased (see table above).
The required pre-pressure is:
Pg=(H/10+0.3) bar=(0/10+0.3) bar=0.3 bar
The corresponding maximum water volume can be read from
the graph: approximately 380 l for leaving water of 65°C and
approximately 250 l for leaving water of 80°C.
In case of 65°C leaving water, since the total water volume
(380 l) is not higher than the maximum water volume (380 l), the
expansion vessel suffices for the installation.
In case of 80°C leaving water, because the total water volume
(380 l) is higher than the maximum water volume (250 l) of the
expansion vessel, an additional expansion vessel must be
installed.

Setting the pre-pressure of the expansion vessel

When it is required to change the default pre-pressure of the
expansion vessel (1 bar), keep in mind the following guidelines:
Use only dry nitrogen to set the expansion vessel pre-pressure.
Inappropriate setting of the expansion vessel pre-pressure will
lead to malfunction of the system. Therefore, the pre-pressure
should only be adjusted by a licensed installer.
To be able setting the pre-pressure of the expansion vessel, the
switch box needs to be removed from the unit. How this must be done
is explained in the chapter

Connecting the water circuit

Water connections must be made. The location of the water inlet
connection and the water outlet connection on the indoor unit is
shown in the chapter
Be careful not to deform the unit piping by using excessive
force when connecting the piping. Deformation of the
the
piping can cause the unit to malfunction.
If air, moisture or dust gets in the water circuit, problems may occur.
Therefore, always take into account the following when connecting
the water circuit:
Use clean pipes only.
Hold the pipe end downwards when removing burrs.
Cover the pipe end when inserting it through a wall so that no
dust and dirt enter.
Use a good thread sealant for the sealing of the connections.
When using non-brass metallic piping, make sure to insulate
both materials from each other to prevent galvanic corrosion.
Because brass is a soft material, use appropriate tooling for
connecting the water circuit. Inappropriate tooling will cause
damage to the pipes.
The unit is only to be used in a closed water system.
Application in an open water circuit can lead to
excessive corrosion of the water piping.
Never use Zn-coated parts in the water circuit.
Excessive corrosion of these parts may occur as
450
copper piping is used in the unit's internal water
circuit.
NOTE When using a 3-way valve or a 2-way valve in the
water circuit, the maximum changeover time of the
valve shall be less than 60 seconds.
"Opening the unit" on page
"Main components" on page 6.
33.
Installation manual
12