Well System Pressure Overload - Grundfos SQE Montage- Und Betriebsanleitung

8.3 Well system pressure overload

In order to provide protection against overpressure,
install a pressure relief valve downstream of the well
head. The setpoint of the pressure relief valve must
be at least 30 psi above the pressure setting.
If you install a relief valve, we recommend that you
connect it to an appropriate drainage point.
Pmin
0.6 0.8 1 1.2 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8
[m]
25 8 8 18 18 18 18 24 33 33 50 50 50 50 80 80 80 80 80
30 8 8 18 18 18 24 33 33 50 50 50 50 80 80 80 80 80
35 8 18 18 18 18 24 33 33 50 50 50 80 80 80 80 80
40 8 18 18 18 18 24 33 50 50 50 80 80 80 80 80
45 8 18 18 18 24 33 33 50 50 50 80 80 80 80
50 8 18 18 18 24 33 50 50 50 80 80 80 80
55 18 18 18 18 24 33 50 50 50 80 80 80
60 18 18 18 18 24 33 50 50 80 80 80 80
65 18 18 18 24 24 33 50 50 80 80 80 80
1 m head = 0.098 bar.
Using Pmin and Qmax, the minimum diaphragm
tank size, precharge pressure and pressure switch
settings can be found in the guideline table below:
Example
Pmin = 35 m head, Qmax = 2.5 m
On the basis of this information, the following values
can be found in the table:
Minimum diaphragm tank size = 33 litres.
Ppre
Pcut-in
Pcut-out = 50 m head
3
Qmax [m /h]
Diaphragm tank size [litres]
3
= 31.5 m head
= 36 m head
Ppre
[m]
22.5
27
31.5
36
40.5
45
49.5
54
58.5
/h.
Pcut- Pcut-
in out
[m] [m]
26 40
31 45
36 50
41 55
46 60
51 65
56 70
61 75
66 80
15