Samsung RC***MHXGA Installation Manual page 25

Setting capacity and 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.
Installation height
difference
(a)
<7m No pre-pressure adjustment required.
Actions required:
• Pre-pressure must be increased, calculate the
appropriate value following by "Calculating
>7m
the pre-pressure of the expansion vessel".
• Check if the water volume is lower than
maximum allowed water volume
(a) Installation height difference: height difference(m) between the highest point of the water circuit and the indoor unit.
If the unit is located at the highest point of the installation, the installation height is considered 0m.
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
2.5
2.0
1.5
Operation range
1.0
0.5
0.0
150 200 250
Total water volume(ℓ)
< 220 Litres
300 350
Water volume
> 220 Litres
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
Expansion vessel of the unit too small
for the installation.
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