Setting The Pre-Pressure Of The Expansion Vessel; Connecting The Water Circuit - Rotex RKHBH008BA Manuel D'installation

3 Using the table and instructions below, determine if the total
water volume in the installation is below the maximum allowed
water volume.
Installation Water volume
height
≤
(a)
280 l
difference
No pre-pressure adjustment
≤
7 m
required.
Actions required:
• pre-pressure must be
increased, calculate according
to "Calculating the pre-
pressure of the expansion
>7 m
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 calculated
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 10 50 100 150 200
maximum water volume [l]
= pre-pressure
= maximum water 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.
Installation manual
15
>280 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)
Expansion vessel of the unit
too small for the installation.
pre-pressure (Pg) the
250 300 350 400 450
Example 2
The indoor unit is installed at the highest point in the water circuit.
The total water volume in the water circuit is 350 l.
Result:
■
Since 350 l is higher than 280 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 410 l.
■
Since the total water volume (350 l) is below the maximum water
volume (410 l), the expansion vessel suffices for the installation.

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.

Connecting the water circuit

Water connections must be made in accordance with local
regulations and the outlook diagram delivered with the unit,
respecting the water in- and outlet.
NOTE Be careful not to deform the unit piping by using
excessive force
Deformation of 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.
The sealing must be able to withstand the pressures and
temperatures of the system.
■
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.
■
NOTE 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
copper piping is used in the unit's internal water
circuit.
■
When using a 3-way valve in the water circuit.
It is very important to guarantee full separation
between domestic hot water and floor heating
water circuit.
■
When using a 3-way valve or a 2-way valve in the
water circuit, the maximum change over time of
the valve shall be less than 60 seconds.
Indoor unit for air to water heat pump system
when connecting the piping.
RKHBH/X008BA
4PW54224-1A