air compressor safety valve keeps opening free sample

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.

A question we commonly receive is why a valve appears to open, or actuate, earlier than expected. Often, we find that the valve is not, in fact, opening early. Rather, the perception that it is actuating early is due to a misunderstanding of set pressure.

The set pressure, also called the opening pressure, of a safety or relief valve is the inlet pressure at which the valve begins to open as required by code.

A valve should be set to open at the maximum allowable working pressure (MAWP) of the vessel the valve is intended to protect. There is some tolerance to actual set pressure, which means that a valve set at 100 psig may open slightly above or slightly below this level.

The first step is to determine if your valve really is opening early. Sometimes safety and safety relief valves appear to open before they reach the set pressure — there may be an audible or visible release of fluid between the seat and the disc. This is known as “simmer” or “warn,” and it is not the same as a full open.

Simmer, or warn, occurs when a valve opens slightly, discharging only a small percentage of its rated capacity. For example, direct spring-operated safety valves may simmer or warn at 90% of the nameplate set pressure. A valve that is simmering is not considered open.

The next step is to check your gauge to ensure that it is reporting the set pressure correctly. The gauge should be calibrated properly and located upstream of the valve, close to the valve inlet. Rapid increases in system pressure can make it appear that a valve is opening early because the gauge can’t accurately report the pressure.

If you still believe your valve is opening early, assess the operating factors that might be contributing to the situation. Valves are factory set using standard conditions, and factors like high temperature, vibration, and back pressure can cause them to open early. These conditions can be compensated for using cold set pressure, aka cold differential test pressure (CDTP). Learn more about CDTP from the National Board.

Hello, my tank which max at 175 psi, will run and shut off normally, except PRV at the start of intercooler pops air every 1/2 second or so until the compressor hits 175 psi.

I figured I had to have a valve hanging open or closed so I started removing the manifolds’ looking for a stuck or malfunctioning valve. All valves were free and could not see any problems. I reassembled the unit and still had the same problem.

Still, if this is a 2-stage compressor, and I believe it is, and the low pressure cylinder feed line to the higher pressure cylinder has it’s PRV let go, and it’s not the PRV itself, I’d still think it was the valve on the high pressure cylinder reacting to pressure some how.

My compressor builds up pressure fine but when it gets to the normal cut off the pvr opens n releases the air down to about 40 psi so it keeps running the motor could it be the pressure switch? Thanks

If the pressure switch fails with current passing it to the motor, the compressor will continue to run and pump pressure into the tank, until the tank pressure reaches the PRV release pressure point, and the PRV opens to vent overpressure.

You say “gets to the normal cut off the pvr opens n releases the air” then if the PRV is opening at the pressure switch normal cut out pressure setting, then it is the PRV that is suspect, not the pressure switch.

If I cut the power before the safety trips and then put it back on,the pumps stays off while I use the tool (nail gun or stapler) and when the pressure drops by around 30psi the compressor comes back on. So as long as I substitute for the max pressure switch I can work. It used to work and I don’t know if I have done something that has made the safety operate too low or if I have somehow set the Max switch too high.

Jan, if by the safety trip you mean the PRV lets go to bleed off excessive pressure, then it is either that you have adjusted the compressor cut out setting to a set point higher than the PRV release pressure, or the PRV is failing.

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.

Conventionally when we talk about oil lubricated screw air compressor maintenance, it is mostly about replacing consumables such as filters and lubricant on time. While these consumables have a defined usable life and have a direct effect on the efficiency and the life of the air compressor itself when not replaced on time, there are a few critical valves in the air compressor that require maintenance as well. Compressor valves directly affect the efficiency, safety, and the functionality of the screw air compressor. Let us understand some of the commonly available valves in a screw air compressor, why they need maintenance, and discuss some of the frequently asked questions about screw air compressor valves.

A screw air compressor is very similar to a human heart. While a human heart has tricuspid, pulmonary, mitral, and aortic valves, a screw air compressor has four critical valves namely air inlet, minimum pressure, blow down, and safety valves.

Air inlet valve is also commonly known as the ‘Intake valve’ which is typically assembled on the airend’s intake. The air inlet valve of a conventional fixed speed screw air compressor controls the air intake into the compressor. It remains closed when the compressor starts to lower the starting load on the main motor and when the desired working pressure is attained in the compressed air circuit and thus enabling the compressor’s motor to run without any load. In some compressors that are capable of providing a variable output by modulating the amount of air it sucks in, the inlet valve holds various opening positions to regulate the volume of air entering the compressor. The effective performance of the inlet valve directly affects the compressor’s capacity and its power consumption during load and no-load conditions.

The minimum pressure valve is typically assembled on the exit of the air-oil separation tank of a compressor. The minimum pressure valve acts as a check valve preventing back flow of compressed air into the airend, retains a minimum pressure in the compressor system for lubrication, offers a restriction to avoid a collapse of the air-oil separation filter, and ensures a suitable velocity of flow across the air-oil separator that ensures efficient air-oil separation. The effective performance of the minimum pressure valve directly affects the compressor’s lubrication, air-oil separation efficiency, and power consumption during load and no-load conditions.

The blow down valve is typically found on a dedicated exhaust line from the air-oil separation tank. The blow down valve evacuates the compressed air in the air-oil separation tank each time the compressor runs on a no-load and when the compressor shuts down to ensure there is no back pressure when the compressor starts to load next time. The blow down valve of a conventional screw compressor is typically actuated by a solenoid valve. The effective performance of the blow down valve affects the compressor’s power consumption during un-load, capacity of the compressor when running on load, and the life of the motor.

The safety valve is typically mounted directly on the air-oil separator tank. The only function of the safety valve is to blow off the compressed air in the air-oil separation tank when the pressure in the air-oil separation tank exceeds the set pressure of the safety valve and there by prevents the tank from cracking under high pressure. A malfunctioning safety valve affects the safe operation of the air compressor or results in leakage of compressed air continuously.

Though each compressor manufacturer has their own unique valve design, compressor valves in general contain moving parts such as springs, valve plates, and plungers that affect the opening and closing of the valves and rubber seals / seats that offer perfect sealing when the valves remain closed. These moving parts wear or lose their mechanical properties over a period of time and the sealing components typically ‘age’ over time and lose their effectiveness and will need to be replaced.

Compressor manufacturers typically design these components to operate efficiently for several thousand or millions of operation cycles. However, several factors such as variability in the demand pattern, sizing of the air compressor against a certain air demand, the environment in which the air compressor operates, promptness of preventive maintenance, etc. determine how long these valves efficiently operate.

Many times, it is difficult to identify a malfunctioning valve or a valve operating with worn-out parts as the compressor continues to generate air. The typical symptoms of a malfunctioning valve are loss in compressor"s capacity, increase in power consumption during load or/and unload, drop in discharge pressure, increase in oil carry-over and more load on motor. These symptoms are either difficult to notice or have other frequently common assignable causes such as air leak before suspecting the compressor valves.

Case studies show that operating a screw air compressor with a worn-out / malfunctioning valve could increase its overall power consumption by 10 - 15%. Power cost contributes to more than 75% of the compressor’s total life cycle cost over ten years and hence this is a significant impact. Unserviced valves also lower the life span of downstream accessories by half. In some cases, a malfunctioning safety valve may result in a catastrophe.

Air compressor manufacturers typically offer convenient valve maintenance kits for customers that contain the internal parts of the valve that wear or age out. Changing the valve kits is a much more sensible and economical option than changing the complete valve.

It is difficult or almost impossible to identify a malfunctioning valve unless it is opened for inspection. Hence it is absolutely mandatory that these valves are inspected for effectiveness every year and the internal moving parts replaced as a part of preventive maintenance once every year or two depending on the operating conditions of the air compressor. It is typical for compressor manufacturers to mandate a valve kit replacement once every two years as a proactive measure.

In particular, the safety valve must be inspected and certified every year per the local safety laws to ensure they are functional and efficient. Sometimes, replacing the safety valve entirely with a valid certificate for one year is more economical as the certification procedures could be equally expensive on an existing valve.

As stated before, it is challenging to identify a valve that is worn out unless it is opened and inspected, but there are a few indicators that a qualified compressor technician can use to deduct a malfunctioning valve.

Low duty cycle operation: A sophisticated screw air compressor in today’s day and age carries a convenient microprocessor-based human-machine interface that keeps track of operating hours of the compressor under load and un-load conditions and the number of load/unload counts the compressor is subjected to over a period of time. A higher un-load hours and load/unload count indicates that the air compressor is oversized against the actual air demand. This in turn indicates the air compressor ‘cycles’ frequently between load and un-load mode as opposed to running continuously on load. Every time a compressor ‘cycles’, the inlet valve, blow down valve, and minimum pressure valve is brought into play where their internals ‘actuate’. Frequent actuation of these valves results in a faster wear of the internals and hence results in shorter life.

High operating temperature: A compressor that runs on a high operating temperature affects the life of the valve’s sealing components, which causes them to ‘age’ fast.

Compressor not building pressure: If the air demand has not changed over time and the facility is relatively free of any air leakage, the air compressor is probably not delivering the rated output. There is a high probability that there is a malfunctioning valve.

Increase in compressor’s power consumption: An increase in the air compressor’s power consumption profile over a period of time where there has been no abnormal change in the air demand and usage pattern indicates an increase in either the load or un-load power. There is a high probability that this is because of a malfunctioning valve.

Based on the design philosophy adopted by the air compressor manufacturer, the oil lubricated screw air compressors could have a few more valves that are critical to functional performance that must be maintained as well. Some of the other valves frequently used in an air compressor are as follows:

Temperature control valve (also known as thermal valve) is used to regulate the flow of oil through the oil cooler based on the operating temperature.

Drain valves are used to drain lubricant at the time of lubricant change over or cleaning. Air compressors equipped with a moisture trap at the outlet of the after cooler also has a drain valve (automatic or timer based) to discharge water collected.

The presence or absence of one of these valves and the type of actuation of these valves (electronic / mechanical) depends on air compressor’s design architecture. The Operation and Maintenance Manual (OMM) and the Piping and Instrumentation Diagram (P&ID) supplied by the air compressor manufacturer are excellent resources that explain the purpose, functioning, and maintenance requirements of these valves.

Many of the air compressor valves are highly specialized and exclusive. Their designs are usually complex and some even need special tools to service them. The internal components" build quality and material selection are extremely important and proprietary. Hence it is highly critical that only genuine valve kits issued by the air compressor manufacturer are used to maintain the valves. An inferior after-market replacement will most certainly compromise the performance of the entire compressor, void the original manufacturer"s warranty of the compressor, cause consequential damage to other parts of the compressor, and above all, be a safety hazard.

In conclusion, while it is important to change the screw air compressor"s filters and lubricants on time, it is equally important to perform preventive maintenance on these critical valves in a screw air compressor as recommended by the air compressor manufacturer. While the intake valve, minimum pressure valve, safety valve, and blowdown valve are critical to the performance and safety of the compressor, there could be other valves in the compressor that are critical and need maintenance. The air compressors sizing and the environment in which it operates are crucial factors that affect the life of the air compressor. Finally, it is critical to proactively service these valves using genuine kits issued by the compressor manufacturer to enable the air compressor performs efficiently and safely.

Gershom Joel has over 15 years of experience in the compressed air field and specializes in helping industries such as Pharmaceuticals, Textile, Electronics, and Food and Beverage find compressed air solutions to meet their unique requirements.  Gershom holds a Mechanical Engineering Degree from Anna University and a Masters in Business Administration from University of North Carolina.

ELGi North America, headquartered in Charlotte, NC, is a subsidiary of ELGi Equipments Limited, a leader in compressed air solutions for over 60 years. Established in 2012, ELGi North America, in conjunction with its subsidiaries, Pattons, Pattons Medical, and Michigan Air Solutions, offers a comprehensive range of compressed air products and services. Our product offering includes oil-lubricated and oil-free rotary screw and reciprocating compressors, dryers, filters, and ancillary accessories. ELGi and its subsidiaries serve multiple industry verticals spanning medical applications, pharmaceuticals, food & beverage, construction, manufacturing, and infrastructure. For more information, visit https://www.elgi.com/us/.

An OSHA COMPRESSED AIR SAFETY SHUT-OFF VALVES should be placed immediately after the air control shut off valve and before the hose on a compressor, and after each discharge port that a hose is connected to.

Before starting the compressor the air control valve should be closed completely. When the compressor unloads, open the air shut off control valve very slowly. Full port ball valves tend to work better than gate or butterfly type valves.

The air shut off control valve must be fully open for the OSHA COMPRESSED AIR SAFETY SHUT-OFF VALVES to work. Some portable air compressor manufacturers recommend start-up with the air control valve slightly open. In this case you may have to close the valve and reopen it slowly to the full open position, or wait for the safety shut-off valve to reset itself.

If the OSHA COMPRESSED AIR SAFETY SHUT-OFF VALVES fails to operate despite meeting all condi-tions, check the hose line for obstructions or a hose mender restricting normal air flow.

• Turn on air supply slowly (to avoid tripping OSHA safety valve). Prior to fully reaching operation conditions, the OSHA COMPRESSED AIR SAFETY SHUT-OFF VALVES should suddenly activate and stop air flow.

• If the OSHA COMPRESSED AIR SAFETY SHUT-OFF VALVE is not activated the unit should be disconnected and the lower flow range OSHA COMPRESSED AIR SAFETY SHUT-OFF VALVES should be used. This means you need to use a different valve with a lower scfm range.

• At temperatures below 40°F ensure that OSHA COMPRESSED AIR SAFETY SHUT-OFF VALVES are not subject to icy conditions which may prevent proper functioning.

An air compressor problem could stem from one of many issues, such as an air leak, an oil leak or a broken part. In some cases, you might have insufficient pressurization or air flow. In other cases, the compressor might fail to start up or stop running as prompted. Whatever the cause of the problem, the symptoms can be frustrating, costly and time-consuming.

Thankfully, most such problems can be corrected with proper air compressor troubleshooting. The Titus Company has developed this troubleshooting guide for reference when your air compressor won’t work. Whether you’re hearing excessive noise from your portable air compressor or your system won’t build pressure, you’ll find the cause here — and, hopefully, a solution. If not, call us. We’ll be there quickly with our 24/7 emergency services.

Good air pressure is essential to a well-powered machine. When air is leaking from your tank or hoses, you’ll notice low pressure, which brings on extra time and energy costs that can leave your business behind. An air leak could be down to one of several factors. Fortunately, leaks can be sealed with the right kind of air compressor troubleshooting. The following symptoms are among the most common leak-related air compressor problems:

If you shut off the air compressor on full charge, yet the gauge drops while the compressor is deactivated, you definitely have an air leak. The compressor might even automatically restart just to counter the situation. What you need to do in this situation is pinpoint the source of the leak.

Apply soap to the connections: With the compressor unplugged, cover the connections with liquid soap, including all the couplers and the pressure switch. If bubbles form at any point, that is where the leak is located. Tighten up the coupler, if possible, where the bubbling occurs.

Inspect the tank check valve: Air leaks are sometimes caused by tank check valves that fail to close completely. If the pressure gauge continues to drop when the tank is off, access the tank valve and inspect its condition. The valve might need to be cleaned or replaced.

If the air leaks occur only when a hose is plugged into the compressor, disconnect the hose. If the pressure gauge stops dropping, the hose is the source of your leak.

If your compressor is losing pressure through the oil fill tube, check the piston seals. In most such cases, the piston seals will be badly worn and in need of immediate replacement. This is a problem that you should remedy immediately, as worn pistons can cause metal-on-metal friction that could swiftly lead to internal corrosion.

Air leaks from under the hood are sometimes encountered on smaller air compressors. To diagnose the problem, remove the hood, run the compressor for a few minutes, then shut it off and unplug the compressor. Feel around the motor parts for any sort of air draft. Chances are, the leak will originate from the tank valve, in which case you will need to remove and clean or possibly replace the valve.

If you notice an electrical issue, you need to take a look at it or have a professional come out as soon as possible. It could be anything from your motor capacitors to misfiring piston rings. If the power cuts out on your air compressor — or the power is insufficient and unreliable — the problem is most likely down to one of the following factors:

Extension cords: If your compressor is connected to an outlet via an extension cord, the motor could be deprived of sufficient energy, causing the motor to overheat. Compressors are not like home electronics, which can suffice on extension cords and power bars. An air compressor should only be powered through a direct connection to a power source.

An old motor: If your compressor has run on the same motor for many years, it could be time for a change-out. An older motor is liable to have worn windings, loose capacitor wires and other general wear that could easily result in blown fuses and breakers.

An air compressor consumes massive volumes of power at the time of startup. This is known as the inrush, which vastly exceeds the amount of power generally consumed throughout the rest of a usage cycle. To prevent fuses from breaking during this inrush, compressor motors are equipped with starter capacitors, which manage the incoming power. A dimming light is one of the tell-tale signs that the starter capacitor is worn and due for a replacement.

If your air compressor trips off the moment it powers on, the issue is likely caused by trapped air over the pistons. To test for this problem, shut off the tank, unplug it from the power supply and drain the tank of all air. This should relieve the pistons of undue air pressure and allow the tank to start without further issues. Trapped air over the pistons is usually caused by a faulty unloader valve, which should be inspected, cleaned and possibly replaced if the issue persists.

When an air compressor fails to start up, shut down or provide any degree of air pressure while active, the problem could be down to one of several issues. Each case should be taken on its own, as follows:

Aside from the obvious oversights such as a disconnected power cord or a deactivated power switch, a compressor will typically fail to start when it lacks sufficient air pressure. If the cut-in pressure is not proportional to the amount of air pressure stored in the tank, the compressor will often fail to start. Check the cut-in setting on the pressure switch and adjust the level accordingly.

The compressor should stop once the tank pressure drops to the cutoff point. If this fails to occur, the problem will generally be down to one of two issues:

Faulty pressure release valve: If the valve fails to release pressure, the tank will be too pressurized for the motor to stop running. In cases like these, you should cut the power and refrain from further use until the valve is replaced, as further use could seriously damage the compressor.

Faulty pump: If the motor is running and making noise yet no air comes out, you probably have a faulty air-intake pump that needs to be replaced. As long as the compressor is not too hot, you can feel for lack of pump pressure manually with a pair of protective gloves.

Faulty gasket: If the compressor only generates small amounts of pressure, there might be an issue with the gasket between the low-pressure and high-pressure compartments of the compressor, such as air flowing from one side to the other without sufficient pressurization.

Fortunately, pumps and gaskets can easily be changed out. With a simple parts replacement, you should be able to get many more years of performance from the compressor at hand.

If compressor oil works its way into the air lines, the effects could be detrimental elsewhere in the compressor because the pump uses a different kind of lubricant than other parts of the system. Once inside the air lines, that oil will be dispersed to other areas, potentially causing seals to crack or swell. Oily air lines are most troubling when the oil travels to plastic parts of the air valve.

The ill-effects of oil on plastic are due to the additives in the oil, which can cause plastic surfaces to become brittle and ultimately split. A plastic lubricator bowl, for example, could split under such circumstances if the air pressure crosses a certain threshold. You can protect the bowl — or contain the plastic in the event of a rupture — by affixing it with a metal shroud.

In a reciprocating air compressor, the oil must first travel past the piston seals to make its way to the tank. When this occurs, the seals should be replaced immediately. This would also be an opportune time to replace the valve and gasket.

As soon as you notice that oil has entered the air lines, check the sump to make sure that it still has a sufficient quantity of oil. If the problem persists, the sump could be depleted of its oil supply.

When removing the oil, take a look at it and ensure it appears clear and consistent. Sometimes, you may notice your oil has a milky look to it — this happens when your air compressor is exposed to excessive humidity and condensation has gotten into the oil reservoir. In this case, you should drain and replace the oil and move your air intake pipe to a less humid environment.

If you experience these problems, remove the filter housing from the intake pump and run the compressor again. If the problems cease and the compressor runs normally, the issue is rooted in the air intake media. From here, you have two options — cleaning or replacing. To clean a compressor filter, run water through it until you don’t see any dirt particles.

You can replace the media with various types of filter elements sold at supply stores and car parts shops. The best options are media that resemble the kinds used in air conditioners. Cut the media to the dimensions of the intake filter and switch out the old for the new.

The discharge coupler is fitted with the wrong hose connector, thus blocking the flow of air. This could be the case if you recently replaced one of the parts without checking OEM specifications.

If your tank has sufficient air quantity, yet generates very little air pressure, check the gauge readings. If the gauge is too low, you will not get sufficient air pressure from the tank. If your tank gauge is 100 psi, the gauge should be set to somewhere around 90 psi.

If an air compressor seems to have stopped working due to a broken part, you first need to test the part to verify the root of the problem. A compressor will not work if the following parts are broken. Fortunately, all can be replaced:

The intake filter is a crucial part of the air compressor because it strains impure particulates from the incoming air. Since it physically sticks out from the rest of the unit, an intake filter is one of the more easily broken parts to an air compressor. Fortunately, it is also one of the easier parts to replace. As long as you find a filter with the same thread size and roughly the same portal size and diameter, it should work for your machine.

If you break the pressure switch on an air compressor, you might be surprised by the underlying complexities. Fact is, any old replacement switch will not solve the problem due to all the connecting points of the manifold. To fix the problem, you will need to find a switch that accommodates each of the four or five connecting points, which will generally include sockets for the pressure relief valve, the air tank gauge, the compressor tank and the quick coupling.

Before you buy a new pressure switch and manifold, take note of the following details on the old switch, each of which must be matched on any new switch you attach to the compressor:

Many newer air compressors — particularly those on the lower-cost end of the spectrum — blow air with fans made of plastic, which is less expensive than metal but is also more easily prone to wear and tear. Fortunately, a replacement fan made of either material will work in almost any compressor. Therefore, if you have a fan with broken plastic blades, you could turn this into an opportunity to upgrade to metal.

Before you pick a replacement fan, check the compressor manual for a listing of the part number and corresponding dimensions. If not found, measure the dimensions and the hole diameter of the original fan. Take note of the number of blades and the direction of airflow, as both details are consequential to the performance and make of the compressor.

If the motor of your air compressor fails to power on when you flip the switch, it could be a matter of the switch itself, though you should run some tests before you draw any conclusions. Check the power cord to ensure that it is plugged into a functioning socket. If the power switch still fails to activate the compressor, plug a light or electronic device into the outlet to see if that powers on.

If the outlet works for other devices but not your compressor, pull back the housing that confines the switch, remove it from the socket and check the compressor owner’s manual for specs on the switch. Make sure that your replacement switch will match the specs and fit the socket.

Air compressors serve all kinds of purposes on a professional as well as personal scale. From pressing plants and factories to repair shops and studios, pressurized air is used to assemble everything from automobiles and aircraft to appliances and home furnishings. Today’s compressors are designed to deliver optimal power with sleek designs through many usage cycles.

At The Titus Company, we offer maintenance on a variety of air compressor types and brands. Contact us today to learn more about our products and services and how we can help you fix an air compressor that won’t work as intended.

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