Gree SXVD200LCJ2/A-M - Page 84

AIR-TO-WATER HEAT PUMP INSTALLATION
79
expansion vessel.
Example 2： The indoor unit is installed on the highest spot of the water system and
the total water volume is 350L.
① As the volume of water system is higher than 280L, it is necessary to adjust the
pressure of the expansion vessel be lower.
② The formula of calculating pressure
( /10 0.3) (0/10 0.3) 0.3
g
PH
=
+= +=
Bar
③ The maximum volume of the water system is about 410L. As the actual volume of
the water system is 350L, the expansion vessel meets the installing requirement.
④ Adjust the pre-set pressure of the expansion vessel from 1.0Bar to 0.3Bar.
Selection of expansion valve
Formula:
1
2
v=
1
1
1
ce
p
p
⋅
+
−
+
v--- Volume of expansion vessel
c --- Total water volume
1
p
--- Pre-set pressure of expansion vessel
2
p
-- 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 expansion factor in different temperature
Temperature（℃）
Expansion factor
e
0 0.00013
4 0
10 0.00027
20 0.00177
30 0.00435
40 0.00782
45 0.0099
50 0.0121
55 0.0145
60 0.0171
65 0.0198
70 0.0227
75 0.0258
80 0.029
85 0.0324
90 0.0359
95 0.0396
100 0.0434