In this blog post, we are going to look at 3 Solenoid Valve problems which can occur, some ways to identify them and how these problems can be resolved.
Normally the cause for a solenoid or coil failure is very miniscule and can be fixed without any major changes being made. In a more serious case it could call for a coil or valve to be replaced.
3 Solenoid Valve Problems
1. Solenoid Coil Burning Out
Sediment or other matter lodged in the armature.
- Solution - Isolate and dismantle the valve, clean the interior with solvent and compressed air and if necessary, install a filter upstream of the valve. The inside of a solenoid valve is machined to a high tolerance. Scraping the inside of a solenoid valve could cause damage - never clean by scraping with sharp tools. There is also a need to consider if the fluid is reacting with the valve construction materials causing corrosion. An alternative construction of the valve may be required.
Bent guide tube.
The solenoid valve could have been dropped, knocked accidentally or the valve may have been installed by winding onto the pipe using the coil as a lever. Check straightness of the armature and free movement of the plunger against its spring.
Only install solenoid valves using appropriately sized spanner on the end connections.
- Solution - Replace the armature / install the valve correctly / protect the coil from possible knocks.
Another potential cause of burnt-out coils is water ingress between the coil and armature
- Solution - Shield the coil from water or relocate the valve to a dry location.
Burnt out coils are usually the most common problem we see with solenoid valves, this is mainly due to sediment or debris entering the media or the media containing particles.
What will happen:
The debris will block the orifice of the Solenoid valve and will potentially block the diaphragm.
The coil will continue trying to operate the valve (open or close).
Due to the blocked orifice the coil will over heat and burn out.
This normally means that the coil will have to be replaced as it will no longer be able to function.
V-Flow Solutions sister company M&M International UK can offer a wide range of replacement solenoid coils.
You can view the range of coils here.
2. Solenoid Valve Not Working
A valve could not be functioning correctly for a number of reasons. However, the causes of these problems are usually not so severe, they are generally cause by a slight mistake in the installation or setup of the valve.
If you are having trouble with your solenoid valve / or it is not functioning correctly, please check the following:
1. The solenoid valve is connected in the correct direction - port 1 upstream. port 2 downstream, or look for an arrow on the valve body indicating the direction of flow.
2. The supply voltage matches that shown on the solenoid coil (within 10%)
3. Pilot-operated valves and Assisted-lift valves - that you don't have vacuum downstream of the valve (you cannot 'suck' through pilot-operated solenoid valves).
4. That you don't have any back pressure (downstream pressure greater than upstream pressure).
5. Isolate the valve from voltage and fluid, remove the top nut, ID plate, coil and armature, taking care not to lose the plunger and spring inside. Check for sediment, debris or corrosion inside the armature and that the plunger is free to move.
6. Pilot-operated valves and Assisted-lift valves - remove the upper valve body and check the diaphragm inside for any debris or tears.
3. Damaged Seals / Seal Compatibility Issues
Specifying the media is very important for solenoid valves as the seal material needs to be correct in order to determine which seal material is used.
If the seal is not compatible with the media then it could cause problems, this would be because the seals could deteriorate or degrade due to the harshness of the media.
Generally this wont be a problem, as the valve supplied should be compatible, in terms of both valve material and seal material.
However in the unlikely case that there is a problem, here is a list of common seal materials and medias they are compatible with:
- NBR: Should be used for air, water, neutral gases, diesel and in general, it is resistant to oils and grease from -10°C to +99°C.
- EPDM: For hot water and steam. It is resistant to bases and acids in weak concentrations from -40°C to +140°C. EPDM seals should not be used for media containing oil.
- FKM: Combines most of the characteristics of NBR and EPDM and is particularly suitable for hot water and hydrocarbons from -10°C to +140°C.
- PTFE: Is practically resistant to all media. It is rigid and is used from -20°C to +180°C
SIGODUR (Filled PTFE) and RUBY: are stiff materials particularly suitable for heavy duty applications.
- Kalrez R perfluoro elastomer: from DuPont is designed specifically for the chemical process industry, combines innovative polymer and cure technology to give outstanding performance in the widest possible range of chemicals and temperatures. This product is an excellent choice to be used with acids, bases, amines, steam and many other aggressive chemicals. The maximum working temperature is a lot higher than the limits indicated for the coil.
Cautions, Installation and Maintenance of Solenoid Valves
- This product will contain fluid under pressure. Improper use could be dangerous and damage people and things. This product is not a safety device and must not be used as a sole device to prevent the over-pressure of some parts of the plant or the containment of dangerous fluids.
- Read carefully the manufacturer's instructions before installation, start-up and maintenance.
Check for the operating conditions on the product label and on the technical documents (pressure, temperature, fluid, electrical supply) before installation, start-up and maintenance.
- Respect the flow direction indicated with an arrow on the valve body: the flow is from port 1 for 2-way valves and from port 2 for 3-way valves. Valves with an arrow printed on the body can work only in that direction.
- Before disconnecting or disassembling the valve, make sure that there is no pressure inside the tubing or inside the valve itself.
- Use only original spare part supplied by the manufacturer.
- Do no exceed the limits of pressure, temperature and voltage given by the manufacturer and shown on the product label and on the technical documents.
- Do not remove labels from either the valve or coil.
- Check for compatibility between the fluid and the material of the valve before installation and startup. In case of doubt, please contact the manufacturer.
- Always connect the coils earth terminal to ground. Do not use the tubes for the transport of fluids to ground electrical devices.
- Valve must be supported only by the provided connections, where unforseen. Tubes must not transmit static load or vibrations to the valve. Do not use the valve as a support for other equipment or fittings.
- The fixing holes, where provided, or anything else on the valve body must not be modified.
Whilst tightening or unscrewing the valve must be held or revolved only and exclusively by the hexagon on the frameset. The use of other components such as a coil, armature or cover could cause irreparable damage to the valve.
- Care should be taken to prevent foreign bodies - dirt or material chips - from entering the valve during the assembly phase. In those installations where impurities or deposit of various type may infiltrate the fluid, the installation of a suitable filter is recommended.
- Use suitable seal material on the valve threads. In the installations where liquid cement is used, it is important to prevent them from entering the valve and block the movement.
- Do not shut the holes of pilot operated solenoid valve circuit.
- The coil should not be energised before being installed on the valve or without the armature assembly inside since this could cause it to burn out or break.
- Read carefully the manufacturer's instructions before installation and start-up.
- Follow the manufacturer's instruction before installation and start-up.
- The valve can operate in any position. The vertical installation (with upside coil) is highly recommended to avoid any impurity fall into the obturator and to extend the life of the valve.
- A coil can be rotated on its axis by loosening the coil nut and tightening it again (at 4 N/m for valves with brass armature tube and at 7 N/m for valves with stainless steel armature tube) once the coil has been rotated to the most suitable position.
- The coil temperature normally increase during operation (this is a normal condition). Irregular overheating will cause smoke and smell of burning. In this case the power supply must be immediately stopped.
- Install the valve far from sources of heat and in environments where the heat produced by the coil can be easily dissipated.
- It is important to respect the flow direction, the pressure and the technical data on the label.
- Refer to figure 1 (Direct acting solenoid valve) and figure 2 (Pilot operated solenoid valve) to disassemble the internal components of the valve.
- Clean the internal parts disassembling the valve (figure 1 and 2); Remove dirt and dust and then reassemble all the components.
- When purchasing spare parts, ALWAYS mention the model and the code of the valve (indicate on the valve plate) and the date code (mentioned on the coil label).
Solenoid valves are usually robust and reliable, however there can be times when a problem will occur.
Usually, the problems a solenoid valve will run into will be very rare. As long as the specification is correct, the valve should fit the application perfectly.
In the case of a problem, the tips listed in the blog post above should be more than enough to fix the issue.
Maintaining solenoid valves is very important to keep them working at an optimal level, regulation and maintenance play a key role in getting the most out of the product.
Hopefully, this blog has helped you learn how to deal with some solenoid valve problems, but if you need any technical help please don't hesitate to contact the technical team at V-Flow Solutions. We are happy to help in any way that we can.
You can contact us by;
Email: firstname.lastname@example.org or Phone: 01234 855888
You can view the M&M International Home Page here.
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