22
Notes:
1. When the water system side of multiple hydro
modules are connected in parallel and heat water for a
single water tank, you need to set master and slave
hydro modules. The temperature sensor of the water
tank is connected to the master hydro module and the
master hydro module sends the water tank temperature
to the slave hydro module.
2. Only the wired controller connected to the master unit
can be used to set the desired water tank temperature.
The master unit is used to control the switch of the
circulating water pump.
In all the preceding installation scenarios, it is
recommended that the automatic air discharge
valve should be installed at the highest point of
the water system.
STATEMENT
7 PUMP MODEL SELECTION
8 SELECTION OF EXPANSION
TANK VOLUME AND PRESET
PRESSURE
The water pump should meet the flow requirements of
the hydro module. The rated flow of the hydro module is
2.4 m3/h, while the allowed flow range is [1.2, 2.9] m3/h.
The water pump model is based on the calculation of the
water resistance and pipe resistance of the hydro
module. The hydro module fluid pressure is as shown in
the following figure.
0
5
10
15
20
25
30
35
40
0.50 1.00 1.50 2.00 2.50 3.00 3.50
ESP [kPa]
Available flow range
1.2m3/h~2.9m3/h
flow [m3/h]
Hydro module fluid pressure
Fluid pressure
[KPa]
P1
P0
Q1
For example:
Flow rate (m³/h)
Assume that the performance curve of the selected
water pump is as shown in the black figure. When total
water resistance in the water system is P1, the flow rate
is Q1. When Q1 is within the allowed range of the hydro
module, the water pump is suitable. When Q1 is greater
than 2.9 m
3
/h, water pump capacity can be decreased.
When Q2 is less than 1.2 m
3
/h, the water pump capacity
should be increased.
1) Calculating the preset pressure of the expansion tank
2) Calculating the minimum volume of the expansion
tank
=
10
+ 0.3
H---The highest point of the water system is higher than
the hydro module.
If Pg is less than the initially preset pressure of the
expansion tank, you do not need to adjust the preset
pressure of the expansion tank. In general, the initially
preset pressure of the expansion tank is 1.5 bar.
= 0.0693 * / (2.5 - )
Vwater—Total water volume of the water system
Example 1: Total water volume of the water system of a
project is 200 L. The highest point of the water system is
12 m higher than the hydro module. Calculate the preset
pressure and volume of the expansion tank.
Answer: The preset pressure of the expansion tank is 12
/ 10 + 0.3 = 1.5 bar. The required minimum volume of the
expansion tank is V = 0.0693 * 200 / (2.5-1.5) = 13.86 L.
Example 2: Total water volume of the water system of a
project is 72 L. The highest point of the water system is 0
m higher than the hydro module. Calculate the preset
pressure and volume of the expansion tank.
Answer: The preset pressure of the expansion tankPg =
0 / 10 + 0.3 = 0.3 bar, which is 1.5 bar less than the
initially preset pressure of the expansion tank. The
required minimum volume of the expansion tank is V =
0.0693 * 72 / (2.5-1.5) = 4.98 L.
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