21
9.3.
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:
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.
For 4/6/8 units
For 10/12/14/16 units
Installation height
1
difference
Water
volume
<44L
>44L
<12 m
Adjustment is not necessary
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)
﹥
12 m
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.
Installation height
1
difference
Water
volume
<66L
>66L
<12 m
Adjustment is not necessary
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)
﹥
12 m
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.
Note :
(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.
(b) Example 1: The 16kW unit is installed 5m below the highest spot of water system and the total volume of
the water system is 60L.
(c) Referring to the above figure, it is not necessary to adjust the pressure of the expansion vessel.
(d) Example 2: The unit is installed on the highest spot of the water system and the total water volume is 100L.
(e) As the volume of water system is higher than 66L, it is necessary to adjust the pressure of the expansion
vessel be lower.
(f) The formula of calculating pressure
(g)
(h) The maximum volume of the water system is about 118L. As the actual volume of the water system is
100L, the expansion vessel meets the installing requirement.
(i) Adjust the pre-set pressure of the expansion vessel from 1.5Bar to 0.3Bar.
