CLIVET WSAN-YMi 21, Manual For Installation, Use And Maintenance, Page: 47 / 156

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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 to prevent dust and dirt entering.
•
Use a good thread sealant for sealing the connections. The sealing must be able to withstand the pressures and temperatures of
the system.
•
When using non-copper metallic piping, be sure to insulate two kind of materials from each other to prevent galvanic corrosion.
• For copper is a soft material, use appropriate tools for connecting the water circuit. Inappropriate tools will cause damage to the
pipes.
Example 1
：
The unit (16kW) is installed 10m below the highest point in the water circuit. The total water volume in the water circuit is 50 L. In this
example, no action or adjustment is required.
Example 2
：
The unit(16kW) is installed at the highest point in the water circuit. The total water volume in the water circuit is 150 L.
Result:
1. Since 150 L is more than 72 L, the pre-pressure must be decreased (see table above).
•
The required pre-pressure is: Pg(bar) = (H(m)/10+0.3) bar = (0/10+0.3) bar = 0.3 bar
• The corresponding maximum water volume can be read from the graph: approximately 160 L.
•
Since the total water volume (150 L) is below the maximum water volume (160 L), the expansion vessel suffices for the installa-
tion.
Setting the pre-pressure of the expansion vessel
When it is required to change the default pre-pressure of the expansion vessel (1.5 bar), following guidelines:
• Use only dry nitrogen to set the expansion vessel pre-pressure.
• Inappropriate setting of the expansion vessel pre-pressure will lead to malfunctioning of the system. Pre-pressure should only be
adjusted by a licensed installer.
Selecting the additional expansion vessel
If the expansion vessel of the unit is too small for the installation, an additional expansion vessel is needed.
•
calculate the pre-pressure of the expansion vessel:
Pg(bar)=(H(m)/10+0.3) bar
the expansion vessel equipped in the unit should adjust the pre- pressure also.
•
calculate the volume needed of the additional expansion vessel:
V1=0.0693*Vwater/(2.5-Pg)-V0
Vwater is volume of water in the system, V0 is volume of expansion vessel which the unit is equipped(10~16kW,V0=5L,
5~9kW,V0=2L).
CAUTION
Be careful not to deform the unit’s piping by using excessive force when connecting the piping.
Deforming the piping can cause the unit to malfunction.