air compressor safety valve keeps opening manufacturer

If the tank is over pressurized, the pressure switch isn"t shutting off the motor when the air tank fills to the cut-out pressure. Move the pressure switch lever to the off position. If the compressor continues to run, replace the pressure switch, because the switch isn"t shutting off the compressor motor.

If the compressor shuts off when you move the pressure switch lever to the off position, pull the safety valve ring and release all air from the tank. Switch the pressure switch lever to the on position and allow the tank to fill. If the compressor doesn"t shut off when the air tank fills to the cut-out pressure, replace the pressure switch, because the switch isn"t shutting off the compressor motor when tank pressure reaches the cut-out pressure.

Today I am going to explain why this happens and how you can fix it. But first, I would like to give a short introduction about a safety valve and how it works, if you are not familiar with it.

It is also called a pressure relief valve as it reliefs pressure whenever the compressor pressure reaches a critical point. Usually, the pressure level of a safety valve is kept below to the maximum pressure that a compressor can take.

Whenever the pressure of your compressor is about to reach this maximum level, the safety valve will relief air from the compressor so that the pressure drops.

A safety valve follows a very simple mechanism to work. Here is how it actually works –There is a Nozzle inside the valve. From the inlet part of the valve, this nozzle first gets an amount of pressure on it. In other words, the nozzle is there to inlet the air at a certain pressure.

You have to set a pressure level initially for a safety valve. As I have already said, this pressure needs to be lower than the compressor’s maximum pressure level. When the nozzle reaches this pressure, the Disc inside the valve starts to lift and relief the air from the tank.

There is a Spring inside the valve, which is attached to the disc. The spring is made in such a way that it will only bend when the pressure reaches the level you have set. So, the disc is lifted up and drawn down by the spring.

There are a number of components inside a safety valve but it is typically three main components, the nozzle, the disc, and the spring. You have already known how these three components work.

However, if any of these three components get damaged, then the problem begins. For example –If the nozzle is not functioning properly, there will be a problem with the air inlet. In this case, it will accidentally push a lot of air inside the valve and the valve will open.

Finally, if the spring is old or damaged, then it will lift up the disc way before it reaches the set pressure. In this case, air will also discharge from the valve.

Another reason for a safety valve to pop open is when the pressure switch is damaged. A pressure switch has a very serious function in an air compressor. It is set with two pressure level, a cut-out, and a cut-in pressure.

When the pressure switch reads the cut in pressure from the pump, it starts to run the compressor. And, when the pressure reaches the cut-out level, it shuts the compressor down.

In this case, the compressor will go to critical pressure level. When it happens, the safety valve will automatically pop open. This is how the pressure switch is responsible for the safety valve to open suddenly.

There are a number of ways that you can follow to stop a safety valve from opening suddenly. Here are the best ways to keep your compressors safety valve from opening unnecessarily.At first, check if the internal part of the safety valve is damaged or not. If you find a damaged part (i.e. the nozzle or the disc) replace this part and it should be fine.

If you cannot replace the damaged part of the safety valve, you can simply change this safety valve and place a new one. A newer safety valve is always better than a repaired one.

The pressure switch is also responsible for this. So if you don’t find any problems with the safety valve, then check the pressure switch. If the pressure switch is broken, change it.

Sometimes, there are troubles with adjusting the pressure switch. If you are also having trouble, check out this article on air compressor pressure switch adjustment to adjust your pressure switch.

First of all, you need to find out how much pressure your air compressor can take. You will see there is an option to set a pressure level on the safety valve.

When you find out your compressors limit, you can set the pressure level on the safety valve according to that limit. Always use a lower pressure level than the maximum level of pressure that a compressor can take.

The purpose of a safety valve is to discharge air from the compressor when the pressure level reaches too high. High pressure can explode the tank and cause critical accidents. To stop this from happening, a safety valve is used on a compressor.

Most of the safety valves are built to last for years. An average safety valve can easily last for 18 to 24 months. However, you should frequently test your safety valve and change it if there is the slightest chance of malfunctioning. Never take the risk of keeping a faulty safety valve attached to your compressor.

In most cases, you should check your safety valve at least once a month to see if it is in good condition or not. But I recommend you to check at least once every time it discharges.

You already know how to fix it if the air compressor safety valve keeps opening, but it is also important to test the safety valve when it discharges.

Because after discharge it will leave debris around the nozzle and the disc. You have to clean this to keep the safety valve away from malfunctioning.

However, it is not a big issue to fix the safety valve. Depending on the model and the manufacturer of the compressor, the type of valve may vary. So, you will have to act accordingly.

Here we are going to discuss the causes of issues in the air compressor safety valve. Also, we are sharing the steps that you could take to solve the matter.

Suppose you are working with an air compressor for your home garage. Now based on your project, you will set the air pressure. But it is not a surprising fact that the pressure may reach a higher psi. In that case, the safety valve or pressure releasing valve will open and release the access air. Thus, it helps to keep the air compressor safe.

The primary reason for the air compressor safety valve staying open is a damaged pressure valve. It also could be the compressor pressure switch that controls the air circulation in the compressor. A faulty pressure switch won"t be able to shut the motor to control the air, and as a result, the safety valve remains open.

The safety valve attached to the compressor usually comes with a nozzle in it. This nozzle helps to inlet air from the compressor when needed. If the nozzle has any leakage or it is damaged internally, there is a good chance that the safety valve will stay open.

On the other hand, the valve itself could get damaged because of usages. For both of these issues, the relief valve may blow air from the compressor, and you won"t get enough air pressure for your projects. It usually happens when you buy a cheap air compressor without checking the quality.

The Air compressor is built with several parts, and the pressure switch is one of the most crucial parts. The pressure switch is designed to monitor pressurized air from the tank. It reacts depending on the applied pressure on it, and it is used to maintain through a diaphragm.

The pressure switch creates a backward pressure or cut-out pressure when there is high pressure inside the compressor. In that case, the diaphragm will be deformed to break the contact inside the switch and the power will shut down. At this point, you will see the air compressor safety valve keeps blowing.

Now for any reason, if the pressure switch is damaged or not working in the right way, even if the air pressure is not high, it will try to release air through the safety valve. As a result, the relief valve keeps opening even though it is not necessary.

Step-1: Set the pressure limit for the safety valve according to the manufacturer"s instructions. If the pressure limit is lower than the instructed point, reset it by changing the pressure limit

Step-2: Check for the damages to the valve and the nozzle attached to it. If there is an issue with the nozzle and it inlets air without reaching the optimum level, you need to replace it.

Step-4: Inside the compressor, the safety valve used to have a small spring that bends when the pressure reached the level you have set. It lifts the disc in the air compressor to release excess air. If the spring is not bending properly, replace it from the inside.

Step-5: Check the pressure switch of the compressor. Try to identify if it can monitor the cut-in and cut-out pressure. If it fails to monitor the pressure level, probably it is damaged, and you need to replace it.

For air compressor pressure relief valve adjustment, turn off the compressor. Now remove the cover from the valve with a screwdriver. There you will see a big set screw to adjust the pressure. Use a Flathead screwdriver to adjust the screw. If you want to increase the limit, turn the screw clockwise and check the shut-off point. To reduce the pressure level, just turn the screw anticlockwise. Once you find the desired level, attach the cover, and you are ready to go.

If your air compressor PRV valve is faulty and doesn"t work accurately, you need to replace it. To replace the safety valve, you need to remove the previous one. For this, you may have to remove the meter from the top.

Now you should get access to the safety valve. Use a wrench and hold the pressure valve tightly. Turn it anticlockwise until it comes off from the air compressor. Add the new safety valve and secure it at the right point. Apply the wrench to secure the valve and turn it clockwise until it gets set on the compressor.

If you have read the article thoroughly, you won"t be disappointed again if the compressor relief valve keeps opening. Find out the exact issue as described in this article. Solve the problem by following the guideline described here, and you will be ready for the next project.

Listen, if your PRV is going off and the pressure in the tank is higher than the normal cut off pressure for that compressor, that means that the pressure in your tank is above the safety release pressure of your compressor system.

That your pressure continues to rise after your compressor has achieved high pressure cut-out in the tank, and the compressor continues to compress air without shutting off, you’ve got a pressure switch problem.

My ebook, The Home Compressor, covers many aspects of troubleshooting the home compressor, including changing out the pressure switch. Check it out on this site soon if you get the chance.

That your PRV is “popping” at all tells me that your compressor pressure switch cut out pressure level is too high for, or your PRV isn’t suited to, the compressor.

I can’t tell you if the 130 PSI “pop off” is right for your compressor, though that cracking pressure sure seems a bit low, since PRV’s are a safety device and are the last line of defense if the pressure switch fails and prevents a tank over pressure.

If it were me, I’d take the PRV out of the line, and run the compressor, keeping a careful watch on the tank pressure level. Be ready to turn the motor off. Watch the pressure. Maybe the pressure switch is set to shut off at, say, 150 PSI (which is not a too high range normally) and the compressor will shut off then.

That being the case, visit your local compressor repair shop and ask to buy a PRV that opens at about 10 PSI higher than the cut off, and one that needs a manual reset.

Is the aftercooler between cylinders? If so, that would suggest a failing intake valve in the second cylinder. If the aftercooler is between the cylinder and the tank, that may mean a stuck or slow tank check valve.

So about a year ago the original safety valve failed. It kept popping before full pressure. Tank pressure reads 145-150psi when it blows. Tanks rated and used to fill 170ish before it would cut off.

So about a year ago the original safety valve failed. It kept popping before full pressure. Tank pressure reads 145-150psi when it blows. Tanks rated and used to fill 170ish before it would cut off.

You may not worry often, if at all, about whether or not your air compressor is running safely. And you really don’t have to, because compressor manufacturers do. From the pressure rating on the air storage tank to emergency stop buttons, air compressors are designed with safety in mind.

But that doesn’t mean you should never think about your compressor’s safety features. In most cases, they need to be inspected regularly to make sure they’re working properly. One key safety feature that should be inspected regularly is the air pressure relief valve (PRV), sometimes called a safety relief valve.

The pressure relief valve is a safety valve that protects the compressor component that it’s attached to from being exposed to a pressure above its rated maximum operating pressure. This rating, called the maximum working pressure (MWP), is the pressure that the vessel has been certified to continuously operate at safely.

So when a compressor is running at or below its maximum working pressure—in other words, when it’s running “normally”—the relief valve doesn’t do anything.

However, when the air pressure inside a compressor exceeds its MWP, the pressure relief valve will activate to “blow off” the excessive pressure within the compressor. Without a relief valve, the storage tank could rupture from the excessive pressure, damaging the compressor itself, possibly other property near it, and even causing injuries (or worse) to anyone standing nearby.

Before we can talk about how the air pressure relief valve works, we first need to look at how air pressure inside a compressor is managed when everything is running normally.

Under normal circumstances, the air pressure in a compressor is controlled by a pressure switch in an electro/mechanical control system or, in the case of an electronic controller, a pressure transducer and controller settings. When the cut-out set pressure for the pressure switch is reached, the compressor will stop compressing air (unload) until the cut-in set pressure is reached, at which time it will start compressing air again (load). If the pressure switch fails, the compressor would not be able to start compressing air again, or potentially worse, not be able to stop. Most compressors also have a high-pressure safety switch that should stop the compressor if the pressure exceeds the unload set point.

A pressure relief valve is a straightforward safety backup to the pressure switch and high-pressure switch, or the controller set points, should any of these components fail with the compressor running. The safety relief valve is set above the high-pressure safety switch and generally at or below the vessel’s maximum operating pressure. Inside the valve is a spring, and the pressure created by the spring’s tension keeps the valve closed under normal operating conditions. However, as the air pressure increases in pressure vessels (like the storage tank), it eventually exceeds the rated pressure of the relief valve, causing the relief valve to open and the excess pressure to be “blown off” to the atmosphere.

If the pressure relief valve fails open, air will continually vent to the atmosphere, preventing the air stream from becoming fully pressurized. The compressor should be shut down and the relief valve replaced before the compressor is restarted. The open relief valve will likely cause a loss of production and possible danger to personnel as a result of the flow of high-pressure air with flying debris and an unsafe sound level.

A pressure relief valve failing closed presents a potentially more dangerous situation. As noted earlier, the relief valve exists to allow excessive pressure to be “blown off” so that the air pressure inside the compressor’s pressure vessels don’t exceed their rated specifications. If the valve fails closed, this pressure venting can’t happen. Unless compressed air demand matches the compressed air supply, the pressure inside the compressor will continue to build. Eventually, the pressure increase would cause the storage tank to rupture, damaging the compressor and possibly causing additional damage and injury to property and people nearby.

If the relief valve is opening because the air pressure in the compressor has exceeded the valve’s pressure set point, that means the valve is working and doing what it was designed to do. But because this indicates the MWP of the compressor has been exceeded, the condition that’s causing excessive pressure should be diagnosed and corrected.

If the relief valve opening wasn’t caused by excessive pressure inside the compressor, then the valve is most likely “failing open”. Most likely, this is because the valve has become “soft” over time, i.e. the valve spring is providing less counterpressure, so it’s opening at a lower pressure than it should.

Whether the valve opened because of excessive pressure in the compressor or because the valve is failing, you should have your local air compressor distributor inspect your compressor before running it again for two reasons:

First, your distributor can determine whether the valve opened due to a failing relief valve or excessive compressors pressure and perform any needed maintenance or service to get your compressor running efficiently and safely again.

Second, regardless of why the pressure relief valve opened, replacing it may be recommended to ensure safe compressor operation, depending on the valve manufacturer. (Replacement is recommended for Sullair compressors.)

Important: Running the compressor after the relief valve has opened, regardless of the reason why it opened, can put both your property at risk of damage and people at risk of injury (or worse). While this may be obvious if the compressor is building up excess pressure, it also applies if the valve failed open. As noted above, even a valve that fails open poses some risk, and next time it could fail closed.

Given how critical a working air pressure relief valve is to the safe and efficient operation of your air compressor, you may wonder whether you need to do any regular inspecting or testing of the valve to make sure it is working. Because this can vary by manufacturer, you should consult your owner’s manual or contact your local air compressor distributor for frequency and type of inspection needed. For most Sullair compressors, inspection for damage or leakage is recommended, but testing is not recommended, as doing so may compromise the valve’s performance.

However, one thing you should do is schedule regular maintenance with your local air compressor distributor. As part of regular maintenance, a service technician can inspect the PRV and let you know it’s at an age or in a condition at which the manufacturer recommends replacement. Also, problems with the compressor’s performance, e.g. not reaching normal operating pressure, may help the service technician identify a failing relief valve after ruling out other possible causes.

When a pressure vessel like a receiver, sump tank or other storage vessel is purchased separately from the compressor, it may not be supplied with a pressure relief valve. To ensure its safe operation, you should add a PRV.

When selecting a PRV to add to the pressure vessel, you must choose a valve with a pressure set point set at or below the maximum working pressure of the vessel. You will find the MWP (and other useful information) on a tag welded to the pressure vessel. Also, flow capacity of the PRV must meet or exceed the total compressed air supplied to the vessel.

For example, if you have two compressors with capacities of 500 and 750 cfm (14.2 and 21.2 m³/min), and a pressure vessel with a maximum working pressure of 200 psi (13.8 bar), the minimum settings for a pressure relief valve would be 1250 cfm (35.4 m³/min) and a set point 200 psi (13.8 bar) or less.

Finally, when attaching the valve to the vessel, the porting must not be reduced to a size less than the size of the inlet port of the pressure relief valve.

Because the pressure relief valve is critical to the safe operation of your compressed air system, if you’re not sure how to select the correct PRV and properly and safely add it to the pressure vessel, contact your local air compressor distributor. They have the experience and expertise to ensure that the PRV is sized and installed correctly.

The relief valve"s pop off point is a function of exposed surface area vs spring pressure. A light spring, but a very small surface area, will result in a high pressure pop-off point. Using a large valve with a very heavy spring would be the same circumstance, however, the forward flow rating would be substantially different.

An air compressor is not just compressing AIR... it is changing an atmospheric mixture"s pressure, which means MOISTURE will be packed in there, too. Those lines, that cylinder, etc., will all be subject to moisture, and if that moisture content becomes extreme, the internal volume of the cylinder will skyrocket. The pressure relief valve will protect against hydraulic locking, just as much as pneumatic over pressure.

Now... your tank"s inlet valve serves several functions, the obvious being simple reversion. The second, is that the line coming from the compressor TO the tank must be discharged when the pump stops running. Failure to do so, will allow leakback to defeat the reed valves, pressurizing the cylinders and crankcase, blowing out the crank seals and dispersing the crankcase oil around your shop walls and floor, or if not, pushing cool, compressed air, and accumulated condensation, into the crankcase, contaminating, and eventually displacing it"s oil. Bad mojo.

Next, a pressurized compressor does NOT like to start- it needs to come up to speed with no load, which is the UNLOADER"s function. When the compressor stops, the unloader mechanism VENTS the outlet line (from compressor pump to tank) so that the volume is at standard atmospheric on next motor start. Motor start current is high enough across-the-line WITHOUT a load, the unloader facilitates that, in conjunction with the output line, by providing a large-enough-volume for a couple turns of the pump before any substantial pressure builds. It"s a mechanical/pneumatic soft start.

I would certainly renew that main check valve, and also look very closely into the unloader"s operation, and make sure you don"t have a blocked or binding / inoperative unloader... typically it"s a small tube going from that check valve, over to the pressure switch.

What happens when you pressurize an air tank beyond its rated pressure? It fails catastrophically and ruptures in a spectacular way that you wouldn’t want to witness firsthand.

Most air compressors have a number of precautions built in to avoid the risk of a tank rupture. The compressor itself will probably have an automatic shut-off control that turns off the motor once the maximum tank pressure is reached.

In case the auto-shutoff switch fails, there will typically also be a safety valve built into the tank. Such safety valves, such as the Conrader hard seat valve shown above, are rated to specific pressures. A 100 PSI valve will open up at ~100 PSI in order to vent excess air to keep the pressure at or below 100 PSI.

Essentially, safety valves have spring-loaded pistons. Below their factory-set pressures, internal springs hold the pistons downward, creating a seal. But once the pressure inside a tank or device overcomes the built-in pressure limit of a safety valve, the piston is pushed upwards, opening the valve seal to lower and equalized the air pressure.

Safety valves typically also have loops attached to the pistons so that you can manually rapidly depressurize a device or air tank. You should check safety valves every now and then to ensure they can open freely.

There are two main types of safety valves – hard seat and soft seat valves. Hard seat valves are rugged and inexpensive, but typically leak a little bit. Soft seat valves are a little less rugged and more expensive, but they are built with better seals that aren’t as prone to leaking.

I went with Conrader hard seat valve for a recent project, but there are other good brands as well. Safety valves are available in a wide range of pressures and in different styles.

Amazon carries a couple of valves directly and through 3rd party vendors, but your best bet is to check with Grainger, Zoro, McMaster Carr, or another industrial suppliers that have wider selections.

The loud sound of compressed air being blown off can be very annoying keeping in mind that the machine should continue to work in order to minimize downtime.

in this stage compressor is supposed to unload and vent off air in the system preparing it for the next loading phase. But when you have a faulty inlet valve that is letting air in to the screw element, the compressor will keep on producing compressed air even in unload state. So the pressure will keep on building until relief valve can’t hold on and thus it will start to popping to release excess compressed air in the system. Check the seals to identify if they are worn out.

Pressure switch settings. Check setting and correct cut-off pressure if it was tempered with. If you want to increase the cut-off pressure of your compressor beyond its current cut-off pressure then you will have to change pulley, belt and the relief valve to match expected pressure requirement. If you are not comfortable yourself, you can always contact local compressor company so that an expert can come and give you the support you need.

Clogged air/oil separator cartridge. Required pressure differential is always 0.2 bar. When the separator cartridge is starting to get clogged, this pressure differential will start to increase. If your compressor has a pressure gauge on separator tank you can easily monitor pressure difference. Many screw air compressor reads line pressure for it to switch to idle. So with clogged separator that creates big pressure differential means that whilst line pressure is not enough to send compressor to unload state, system pressure in air compressor has build up excessively to the extent it blows compressed air. Try examining the separator.

Faulty relief valve. Sometimes relief valve is usually the problem, more so if it popped up a lot in the past. Check compressor is running as required and if relief pressure is popping within normal pressure range then you will have to change the valve.