Data Sheet
Solenoid valve
Type EV251B
Compact servo operated with assisted lift for general purpose
EV251B with assisted lift is especially suitable
for applications such as closed systems with
low and uctuating pressure conditions or
open systems with dierential pressure down
to 0 bar.
EV251B valves are supplied complete, including
coil and plug.
Features and versions
• For water, oil, compressed air and similar
neutral media
• Clip on coil
• Ambient temperature: Up to 80 °C
• Coil enclosure: IP65
AI236986442833en-000901
Features
EV251B
Body material
Brass
DN [mm]
10-22
Connection
G3/8'' - G1''
Sealing material
NBR
Function
NC
Kv [m3/h]
1.5-3.5
Dierential pressure range [bar]
0-10
Temperature range [°C]
-10-90
Solenoid valve, type EV251B
1 Portfolio overview
Table 1: Portfolio overview
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1
234567899.1
9.2
Coil
Armature
Closing spring
Valve plate
Pilot orice
Diaphragm
Main orice
Equalizing orice
Assist
Assist spring
Assist connector
Solenoid valve, type EV251B
2 Function
2.1 Function NC
Coil voltage disconnected (closed)
When the supply voltage to the coil (1) is disconnected, the valve plate (4), is pressed down against the pilot orice
(5), by the closing spring (3). The pressure across the diaphragm (6), is built up via the equalizing orice (8). The
diaphragm closes the main orice (7), when the pressure above the diaphragm exceeds the inlet pressure below
due to the larger diameter of the upper side and the compression of the closing spring (3). The valve will be closed
for as long as the voltage to the coil is disconnected.
Coil voltage connected (open)
When the voltage is applied to the coil, the armature (2), and the valve plate (4), are lifted clear of the pilot orice (5).
If there is a dierential pressure across the valve, the pressure across the diaphragm (6), drops because the pilot
orice is larger than the equalizing orice. This causes the diaphragm to be lifted clear of the main orice (7). If there
is no dierential pressure across the valve, the armature (2) draws the diaphragm (6) clear of the main orice (7),
using the assist spring (9.1) and assist connector (9.2). The valve will be open for as long as there is voltage to the
coil.
Figure 1: Function NC
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Danfoss
32U1460
ON
OFF
24h
Danfoss
32U9100
Solenoid valve, type EV251B
3 Applications
It is recommended to use a lter in front of the valve. Recommended lter 50 mesh (297 microns).
Figure 2: Filter
In water applications, exercise the valves at least once every 24 hours, meaning change the state of the valve. The
valve exercise will minimize the risk of the valve sticking due to calcium carbonate, zinc or iron oxide build-up.
Figure 3: Exercise: Valve on/o
To minimize scaling, and corrosion attack it is recommended that the water passing the valve have the following
values:
• Hardness 6-18 °dH to avoid scaling (chalk / lime stone build up).
• Conductivity 50 – 800 µS/cm to avoid brass dezincication and corrosion.
• Above 25°C media temperature avoid stagnant water inside the valve to avoid dezincication and corrosion
attack.
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Media
NBR
For water, oil, compressed air and similar neutral media
Media temperature [°C]
NBR
-10-90°C
Ambient temperature [°C]
24V DC
Max 50°C
24V/230V AC
Max 80°C
Kv value [m3/h]
DN10
1.5 m3/h
DN12
2.5 m3/h
DN18
3.5 m3/h
DN22
3.5 m3/h
Min. Opening dierential pressure [bar]
0 bar
Max. Opening dierential pressure [bar
10 bar
Max. working pressure [bar]
10 bar
Max. test pressure [bar]
15 bar
Viscosity [cSt]
Max. 50 cSt
E
V251B 18-22
EV251B 12
EV251B 10
Main type
EV251B 10B
EV251B 12B
EV251B 18B
EV251B 22B
Time to open [ms]
(1)
5060200
200
Time to close [ms]
(1)
300
300
500
500
Solenoid valve, type EV251B
4 Product specication
4.1 Technical data
Table 2: Technical data
Capacity diagram
Example, water:
Capacity for EV251B 10 at dierential pressure of 4 bar. Approx. 3 m3/h
Figure 4: Capacity diagram 10-22
Time to open/close
Table 3: Time to open/close
(1)
(1)
The times are indicative and apply to water. The exact times will depend on the pressure conditions.
The times are indicative and apply to water. The exact times will depend on the pressure conditions.
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Components
Materials
Specications
Valve body
Brass
W.no. 2.0402
Armature
Stainless steel
W. no. 1.4105 / AISI 430FR
Armature tube
Stainless steel
W. no. 1.4306 / AISI 304L
Armature stop
Stainless steel
W.no. 1.4105/AISI 430FR
Springs
Stainless steel
W. no. 1.4310 / AISI 301
O-rings
NBR (Only EV251B 10 - other version are without o-ring)
Valve plate
NBR
W. no. 1.4122
Diaphragm
NBR
Type
Weight gross
valve body with
BB coil
LL1BB1H1
H
[kg]
[mm]
[mm]
[mm]
[mm]
[mm]
[mm]
EV251B 10
0.58
51.58448461381EV251B 12
0.64
58.08454461381EV251B 18
0.94
90.08462461887EV251B 22
0.94
90.084624618
91
H
B
H1
B1
L1
L
Solenoid valve, type EV251B
Materials
Table 4: Materials
4.2 Dimensions and weights
Table 5: Dimensions and weight, brass NC
Figure 5: Dimensions
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Danfoss
32U1776.10
Solenoid valve, type EV251B
4.3 Mounting
Figure 6: Mounting angle
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ISO228/1
connection
Orice
Kv value
Sealing
Coil voltage/power
consumption BB coil
Function
[mm]
[m3/h]
NC
G3/8101.5
NBR
24V DC 18W
032U538002
24V 50Hz 10W
032U538016
230V 50Hz 10W
032U538031
G1/2122.5
24V DC 18W
032U538102
24V 50Hz 10W
032U538116
230V 50Hz 10W
032U538131
G3/4183.5
24V DC 18W
032U538202
24V 50Hz 10W
032U538216
230V 50Hz 10W
032U538231
G1
22
3.5
24V DC 18W
032U538302
24V 50Hz 10W
032U538316
230V 50Hz 10W
032U538331
Coil
Type
Power consumption
Enclosure
Features
BB, clip on
10 W AC.
18 W DC.
IP00 with spade connector
IP20 with protective cap IP65
with cable plug
Cable plug size
Description
Code no.
DIN 18
Cable plug IP65
042N1278
Solenoid valve, type EV251B
5 Ordering
5.1 Parts program
Table 6: Brass, valve body NC
5.2 Accessories
Coil
Table 7: Coils used with EV251B
Cable plug
Figure 7: Cable plug
Table 8: Cable plug
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Type
Voltage
Suitable for coil types
Code no.
BA024A
24 - 240
AL, AM, AS, AZ, BA, BD, BB
042N0185
Solenoid valve, type EV251B
Universal electronic multi-timer Type ET 20 M
Figure 8: Type ET 20 M
Table 9: Universal electronic multi-timer Type ET 20 M
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