Elektrogas VML2 User manual

Printed in Italy - EE162/0704
VML
Solenoid safety valves for Air and Gas
Slow opening and fast closing type
DN10 … DN80
VML2 - VML4
Certified Quality System
www.elektrogas.com

2Printed in Italy - EE162/0704
VML
Slow safety solenoid valve
Class A – Group 2
The VML type valve is a slow opening single-stage
solenoid valve, normally closed.
This type of device is suitable for air or gas blocking and
releasing controls, required in gas power burners,
atmospheric gas boilers, furnaces and others gas
consuming appliances.
The VML type valves are made in accordance with
EN161 standard (EC type examination certificate no.
0063AQ1350).
1- Features
Large range for inlet/outlet connections, from 3/8” to
3" pipes sizing.
Provided with G1/4” pressure gauge on two sides in
the inlet pressure chamber. Others gauge points on
request.
Optional G1/8” connection for closed position
indicator micro switch (on request from 3/4" to 3").
Fine mesh filter incorporated prevents dirty
contamination of the seal seat.
Maximum operating pressure 200 mbar or 360
mbar.
Suitable for air and non-aggressive gases (EN 437,
1, 2 and 3 families).
Easy adjustable flow rate, rapid stroke and opening
time.
Qualified for continuous service (100% ED) and
endless ON/OFF cycles.
Coil insulation is class H (180°C).
Terminal box with PG connector.
The large models are provided with a power saving
electronic device, to reduce power consumption and
working temperature.
Valves are 100% tested by computerized testing
machineries and are fully warranted.
For valve identification see the following charts.
WARNING
- This control must be installed in compliance with
the laws in force.
- Read instructions before use.
- Elettromeccanica Delta S.p.a. reserves the right
to update or make technical changes without
prior notice.
Fig. 1
2- Technical specifications
Connections ……………….. Gas threaded ISO 7/1
from Rp3/8 to Rp2
Flanged PN16 - ISO 7005
DN 40, DN 80
Voltage rating ………………230 VAC 50/60 Hz
Voltage on request …………110 VAC 50/60 Hz
Voltage tolerance …………. -15% / +10%
Power consumption ………. see charts
Environment temperature …-15°C / +60°C
Max. working pressure …….200 / 360 mbar
Flow capacity ……………… see charts
Disc sealing …..…………… NBR
Closing time ………………. < 1 second
Opening time …………….... adjustable from 4 to 25 s
Protection class …………… IP 54 (EN 60529)
Cable gland ………………...PG09
Overall dimensions ……….. see charts

3Printed in Italy - EE162/0704
3- Operation
The VML type valve is a safety shutting device using
auxiliary power supply.
When it is de-energized, the spring pushes on the seal
disc, keeping the gas passage closed. Now, the inlet
chamber is under the gas line pressure, and it forces on
the disc too, improving the seal.
When the coil is powered the valve opens rapidly or
slowly, against the strength of the spring and gas
pressure. The rapid stroke may be adjusted using the
regulating screw on the top (see the Service Instruction
Section), to adjust the initial gas flow. Main flow and
opening time can be adjusted also.
If the power supply is shut off, the valve rapidly closes,
interrupting the gas flow.
4- Accessories
A fine mesh filter is provided, to prevent dirty
contamination of the seal seat. However, an external
strainer must be installed upstream of the valve.
Inlet pressure area is provided with bilateral G1/4"
gauges, to connect min/max adjustable pressure
switches, leakage tester or other gas equipments.
Flanged models are provided with gauges in the outlet
chamber too
On request, valves are supplied with a G1/8” connection
on the bottom, to installed a closed position indicator
micro switch (from 3/4" to 3"). An adapting rod is
provided too.
5- Coil features
The continuous service (100% ED) causes inevitable coil
heating, depending of working environment. This
situation is absolutely normal and has not to worry. To
improve the coil cooling, install the valve allowing free air
circulation.
The models from 1"¼ up to 3" are provided with a power
saving electronic device. It has two stages of operation:
full power is supplied to the coil while the valve is
opening; low power is supplied while the valve is
opened.
Coil and terminal box are provided with suitable gaskets,
to avoid water and dirty contamination (see the Service
Instruction Section).
Fig. 2
6- General information
Backpressure sealing is compliant with the Class A:
the maximum backpressure admitted, with leakage
within the EN161 requirements, is 150mbar.
Maximum torsional stresses admitted are compliant
with the Group 2 of the EN161 standard.
Recommended testing pressure is 1500 mbar Max.
All components are design to withstand any
mechanical, chemical and thermal condition
occurring during typical service.
Effective impregnation and surface treatments has
been used to improve mechanical sturdiness,
sealing and resistance to corrosion of the
components.
Valves are suitable for use with air and non-
aggressive gases included in the 1, 2 and 3 families
(EN 437).
Materials in contact with gas:
•Aluminium
•Brass
•Stainless steel
•Plated steel
•Anaerobic adhesive
•Nitrile rubber (NBR)
•Polytetrafluoroethylene (PTFE)

4Printed in Italy - EE162/0704
7- Valve identification
Connections type 230V AC 110V AC 24V AC/DC 12V AC/DC
Threaded Flanged 360 mbar 200 mbar 360 mbar 200 mbar 200 mbar 130 mbar 200 mbar 130 mbar
Rp 3/8 VML0 VML0B
Rp 1/2 VML1 VML1B
Rp 3/4 VML2 VML2B
Rp 1 VML3 VML3B
Rp 1¼ VML35 VML35B
Rp 1½ DN 40 (1) VML4 VML4B
Rp 2 DN 50 (1) VML6 VML6B
DN 65 (2) VML7 VML72 VML7B VML72B
DN 80 (2) VML8 VML82 VML8B VML82B
Fig. 3
Connections
Overall Dimensions
(mm)
Model
Threaded Flanged
Maximum
Pressure
(mbar)
Power
Consump.
@230VAC
(W) A B C D Int h
Weight
(Kg)
VML0 Rp 3/8 360 20 88 77 180 196 - - 1,8
VML1 Rp 1/2 360 20 88 77 180 196 - - 1,8
VML2 Rp 3/4 360 45 88 96 200 222 - - 2,7
VML3 Rp 1 360 45 88 96 200 222 - - 2,7
VML35 Rp 1¼ 360 45/180 (3) 120 153 258 290 - - 6
VML4 Rp 1½ DN 40 (1) 360 45/180 (3) 120 153 258 290 110 4x18 6
VML6 Rp 2 DN 50 (1) 360 45/180 (3) 106 156 264 302 125 4x18 6,3
VML7 DN 65 (2) 200/360 60/240 (3) 200 305 335 424 145 4x18 14,5
VML8 DN 80 (2) 200/360 60/240 (3) 200 305 335 424 160 8x18 14,5
(1) Optional kit (2) Vstart =3 mm minimum (3) Working/Opening

5Printed in Italy - EE162/0704
mba
r
2
mmH O
DN 65
DN 80
m³/h
1"
1/2"
3/8"
3/4"
1"½
1"¼
2"
Towngas
Naturalgas
Air
8- Loss of pressure
Formula of conversion from air
to other gases
+15°C, 1013 mbar, dry
Gas type Specific gravity
(kg/m³) K
Natural Gas 0.80 1.25
Town Gas 0.57 1.48
Liquid Gas 2.08 0.77
Air 1.25 1.00

6Printed in Italy - EE162/0704
9- Valve installation
Verify the line pressure is lower of the maximum working
pressure admitted to the valve.
Check correspondence of flow direction with arrow
printed on valve body.
Check correct alignment of connecting pipes and allow
enough space from the walls to allow free air circulation.
Remove the end caps and make sure no foreign
body is entered into the valve during handling.
Install in an area that is protected from rain and
water splashes or drops.
Threaded models:
1. Put sealing agent onto the pipe thread (avoid
excessive quantities of fittings glue which could
enter in the valve and damage the seal seat).
2. Screw the pipes using proper tools only. Do not use
unit as lever because damage to the valve stem
could result.
Flanged models:
1. Position the gasket and insert the bolts.
2. Screw the nuts tightening them crosswise and using
proper tools only.
Avoid overtightening and mount tension free.
Following chart shows the maximum values of bending
moment (Fmax), torque (Tmax) and screws driving torque
(Cmax), according with EN13611.
Connections Fmax
(Nm) t<10 s Tmax (Nm) Cmax (Nm)
Rp 3/8 70 35 -
Rp 1/2 105 50 -
Rp 3/4 225 85 -
Rp 1 340 125 -
Rp 1¼ 475 160 -
Rp 1½ 610 200 50
Rp 2 1100 250 50
DN 65 1600 - 50
DN 80 2400 - 50
Fig. 4
Valve may be mounted with coil in horizontal or vertical
position. Coil may be oriented 360 degrees in any
direction.
10- Electrical connections (IEC 730-1)
Check correspondence between valve voltage rating and
line power supply, before making any electrical
connections.
1. Switch off power supply and remove protection
cover.
2. Connect power cables to rectifier circuit terminal
board.
3. Should cables pass through originally closed
opening, use the rubber disc placed underneath the
box plug to close any other opening.
4. Screw back the box cover, taking care to use all
gaskets properly, because this could condition the
valve life duration.
Fig. 5
WARNING
•To prevent product damage and dangerous
situations, read the Installation and Service
Instructions carefully.
•Turn off all power before servicing any part of
the system.
•Perform leak and functional tests after mounting.
A gas leak detection spray may be used also.
•Coil and terminal box must be replaced with
identical spare parts only.
•If the coil is turned, make sure the brake is
properly tightened and the coil is locked.
•Use all gaskets properly (void warranty).
•All wiring must be in compliance with local and
national codes.
•Make sure all works are performed by qualified
technicians only.
Tmax Fmax

7Printed in Italy - EE162/0704
11- Fast stroke adjustment (Vstart)
Fast flow section may be adjusted:
1. Remove plastic cap.
2. Using an hexagonal wrench, turn the outer screw
clockwise to decrease or counter-clockwise to
increase the initial fast stroke.
3. When adjustment is completed, screw back the
plastic cap.
NOTE: in the DN65 and DN80 models the minimum
adjustable stroke is 3 mm.
12- Flow rate adjustment (Vmax)
Flow rate may be adjusted from 0 cubic meters/h up to
the maximum admitted:
1. Remove plastic cap.
2. Keeping the outer screw fixed, use a screw driver to
turn the internal screw clockwise to decrease or
counter-clockwise to increase flow rate (factory
setting is max. flow rate).
3. When adjustment is completed, screw back the
plastic cap.
NOTE: the flow rate regulation can not be lower than the
fast flow section.
13- Opening time adjustment (T)
To regulate opening time, turn the screw located on the
side of the brake. One fourth of a turn clockwise
increases opening time by 2÷3 s, up to a maximum of
about 25 s (slow run).
Factory setting is about 12÷14 s.
WARNING
•Perform the fast stroke adjustment before of the
flow rate adjustment.
•Make sure that capacity adjustments are made
while burner is working.
•Check the regulation is not changed during
reassembly.
•Adjustments below 40% of capacity are
unadvisable because they may cause
turbulence.
Fig. 6
14- Coil replacement
Before to start with coil replacement, make sure it is the
cause of failure.
To perform coil replacement do the following:
1. Make sure an identical one spare part is available.
2. Switch off power supply and remove the box cover.
3. Disconnect the wires from terminal board.
4. To remove brake, turn it counter clockwise.
5. Extract and replace coil.
6. Reassemble following the inverse sequence.
WARNING
•When reassemble, use all gaskets properly.
•Perform functional test after mounting.
•All works must be executed by qualified
technicians only and in compliance with local
and national codes.

8Printed in Italy - EE162/0704
15- Maintenance
To maintain a good performance of the system, almost
once a year, an inspection of the valve is recommended.
External inspection
Turn off all power before servicing any part of the
system.
Check the conditions of the terminal board gasket. If
gasket is deteriorated, replace it with a new one.
Check the electrical connections are clean, dry and
correctly tightened.
Check the conditions of pipe connections: cover them
with a soap solution and check for leakages.
Internal inspection
To make an internal inspection of the valve, do the
following:
1. Close ball valve upstream the system.
2. Remove the coil like shown in the section 14.
3. Using an Allen key, remove the screws on the upper
flange, in cross way. The gas in the valve will come
out during this step.
4. Check the hydraulic brake is free of oil leakages
(small leakages are admitted). If it’s necessary,
replace it with a new one.
5. Check the main O-ring and, if it’s necessary, replace
it with a new one.
6. Clean the internal side of the stem with a clean cloth
and compressed air.
7. Remove the spring and blow it with compressed air.
Check the spring is corrosion free. Take attention to
the assembly direction of the spring.
8. Check the wear conditions of the sliding rings and, if
it’s necessary, replace them.
9. Clean the sealing disc assembly with a clean cloth
and compressed air.
10. Check the conditions of the sealing gasket. If gasket
is deteriorated, replace it with a new one.
11. Clean the sealing lip with a clean cloth. Do not use
tools, because a lip damage could result.
12. Remove the filter and blow it with compressed air.
13. Check the O-ring on the top of stem and, if it’s
necessary, replace it.
14. Reassemble the valve following the inverse
sequence.
To assemble the sliding rings, wind them onto a lower
diameter (ex. Screw driver), then insert them from the
top.
When reassembling, take attention to the correct
position of the sliding rings and spring.
Fig. 8
When the reassembly is finished, verify the correct
sealing between the upper flange and the valve body:
1. Open ball valve to restore pressure into the valve.
2. Apply a soap solution between the upper flange and
the valve body and check for leakages.
3. Remove the soap solution with a clean cloth, before
to reassemble the coil.
WARNING
•When reassemble, use all gaskets properly.
•Perform functional test after mounting.
•All works must be executed by qualified
technicians only and in compliance with local
and national codes.
Cap
O-ring
Stem
Screw
Upper flange
Main O-ring
Spring
Sliding ring
Plunge
r
Disc + gasket
Filte
r
G1/4” plug
Coil assembly
Valve body
Brake
O-ring