27
Model Selection Principles for the Water
Circulation Pump
Water flow range
Example for water system volume calculation:
Water flow in the water circulation pump ≥ rated water flow × 1.1
Closed water circulation system: Water circulation pump lift ≥ (Pipe resistance of the water Partial
resistance of the water Water pressure drop of the unit) × 1.1
Open water circulation system: Water circulation pump lift ≥(Static resistance of the water Pipe
resistance of the water Partial resistance of the water Water pressure drop of the unit) × 1.1
In the case that multiple units share the same pump, the pump lift is calculated according to the circuit that
has the maximum resistance (usually the unit that is farthest away from the pump).
Note: The water flow of the unit should calculate according the water flow range.
The water system is equipped with one UWL030B5 module unit, the set water return temperature is 12°C,
the main water pipe size is DN80, the total length of main water inlet/outlet pipes is 50 m, 10 end fan coils are
normally open, and the internal volumes are all 1.5 L.
Calculation: Volume of main inlet/outlet water pipe =3.14*[(80/2)/1000] 2*50*103=251 L.
Volume of terminal fan coils =10*1.5=15 L.
According to the table above, Vmin.=317 L.
To avoid frequent unit startup/shutdown and alarms, the volume of the water tank should be no less than
Vmin.-V=317-251-15=51 L.
Model
Underground water source
Ring water source
UWL030B5
UWL040B5
UWL030B5
UWL040B5
Using
side
Heat
source
side
Using
side
Heat
source
side
Using
side
Heat
source
side
Using
side
Heat
source
side
Flow
range
Max. value
(m
3
/h)
26.39
15.86
33.54
20.15
24.57
30.81
32.37
40.56
Rated value
(m
3
/h)
20.3
12.2
25.8
15.5
18.9
23.7
24.9
31.2
Min. value
(m
3
/h)
14.21
8.54
18.06
10.85
13.23
16.59
17.43
21.84
