Selection Of Expansion Vessel - Gree GRS-CQ4.0Pd/NhG3-E Owner's Manual

MONOBLOC TYPE
For 4/6units
Installation height 1
difference
＜ 12m
＞ 12m
For 8/10/12/14/16 units
Installation height 1
difference
<12 m
﹥ 12 m
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) 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.
(h) Adjust the pre-set pressure of the expansion vessel from 1.5Bar to 0.3Bar.

7.5 Selection of expansion vessel

Formula:
V--- Volume of expansion vessel
C--- Total water volume
P --- Pre-set pressure of expansion vessel
1
P -- The highest pressure during running of the system (that is the action pressure of safety valve.)
2
e---The expansion factor of water (the difference between the expansion factor of the original water temperature
and that of highest water temperature.)
<44L
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)
<66L
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)
Water volume
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.
Water volume
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.
Bar
23
Air-to-water Heat Pump
>44L
>66L