Sinclair S therm Series Service Manual page 125

(b) Total water volume of 230 liter is default; if total water is changed because of installation condition, the
prepressure should be adjusted to secure proper operation. If the indoor unit is located at the highest position,
adjustment is not required;
(c) Minimum total water volume is 20 liter;
(d) To adjust pre-pressure, use nitrogen gas by certificated installer.
4.5.8 The method of calculating the charging pressure of expansion vessel
The method of calculating the charging pressure of expansion vessel needed to be adjusted is as follows.During
installation, if the volume of water system has changed, please check if the pre-set pressure of the expansion
vessel needs to be adjusted according to the following formula:
Pg=(H/10+0.3)Bar
(H ---the difference between installing location of indoor unit and the highest spot of water system.)
Ensure that the volume of water system is lower than the maximum volume required in the above figure. If it
exceeds the range, the expansion vessel does not meet the installing requirement.
Installation
1
height
difference
<7 m Adjustment is not necessary
1. Pre-set pressure needs to be adjusted
according to the above formula.
﹥ 7 m 2. Check if the water volume is lower than
the maximum water volume. (with help of the
above figure)
Notes
(a) Installation height difference: the difference between installing location of indoor unit and the highest spot of
water system; if the indoor unit is located at the highest point of the installation,the installation height difference
is considered 0m.
Example 1: The 10kW unit is installed 5m below the highest spot of water system and the total volume of the
water system is 230L.
Referring to the above figure, it is not necessary to adjust the pressure of the expansion vessel.
Example 2: The unit is installed on the highest spot of the water system and the total water volume is 300L.
(a) As the volume of water system is higher than 230L, it is necessary to adjust the pressure of the expansion
vessel be lower.
(b) The formula of calculating pressure: Pg=(H/10+0.3)=(6/10+0.3)=0.9 Bar
(c) The maximum volume of the water system is about 300L. As the actual volume of the water system is 300L,
the expansion vessel meets the installing requirement.
(d) Adjust the pre-set pressure of the expansion vessel from 1.0Bar to 0.9Bar.
4.5.9 Selection of expansion vessel
Formula:
V--- Volume of expansion vessel
C--- Total water volume
P1--- Pre-set pressure of expansion vessel
P2-- The highest pressure during running of the system (that is the action pressure of safety valve.)
e---The expansion factor of water (the difference between the expansion factor of the original water temperature
and that of highest water temperature.)
Water volume
≤230L
121
>230L
1. Pre-set pressure needs to be adjusted
according to the above formula.
2. Check if the water volume is lower than
the maximum water volume. (with help of
the above figure)
The expansion vessel is too small and
adjustment is not available.Please
install additional expansion vessel at the
extenrnal water circuit.