Gree GRS-CQ14Pd/NhG-M - Page 94

Installation
4.6.2 Water volume and expansion vessel pressure
Note:
(a) The expansion vessel is 2 liter and 1.5bar pre-pressurized for 4/6/8kW unit; 3 liter and 1.5bar
perpressurized for 10/12/14/16kW unit ;
(b) Total water volume of 44 liter is default for 4/6/8kW unit and 66 liter for 10/12/14/16kW unit; if total
water is changed because of installation condition, the pre-pressure should be adjusted to secure proper
operation. If the 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.
4.6.3 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 theexpansion 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 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:
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 16kW unit is installed 5m below the highest spot of water system and the total
volume of the water system is 60L.
Referring to the above figure, it is not necessary to adjust the pressure of the expansion vessel.