Air compressors are a typical piece of equipment in many sectors, and the pressure relief valve is an integral part. However, if an air compressor pressure relief valve keeps opening, it can be quite problematic.

Your air compressor pressure relief valve keeps opening due to a pressure switch issue or an old spring. Replace the dirty air filter for $50 to prevent premature triggering or consult a technician to troubleshoot further. 

Read on to learn about what an air compressor pressure relief valve is and how it works, why it keeps opening, and the easiest solution!

What is an Air Compressor Pressure Relief Valve, and How Does It Work?

An air compressor pressure relief valve is designed to eliminate and prevent over-pressurization in the system.

Air compressors work by bringing air into a closed cylinder and then compressing it. They use a piston to push the air inside, squeezing it together until it reaches enough pressure to power your tools. Once the air pressure reaches the system’s maximum PSI, it will need to be released.

Air compressor pressure relief valves are there to ease the problem.

How Air Compressor Pressure Relief Valves Work

A typical air compressor will have one or more air compressor pressure relief valves that are triggered to open when necessary.

Pressure relief valves act as the safety backup for when the compressor pressure switch does not shut down the system at a designated PSI. They look like small metal knobs and allow air to push open a metal disc and escape through the valve. 

Air compressors need this safety mechanism in place to release excess air from the system when required, or else excessive pressure will build up in the system and cause chronic damage!

Why Does My Air Compressor Pressure Relief Valve Keep Opening?

Sometimes, the air compressor pressure relief valve can keep opening improperly and without explanation. This impairs your compressor from working properly, and not to mention it is a safety hazard! Fortunately, there are a few identifiers to look out for.

3 Reasons Why My Air Compressor Pressure Relief Valve Keeps Opening:

  • Issue with the pressure switch
  • Old or damaged spring
  • Air intake filter is dirty or clogged

Each of these causes has a unique solution- most of which can be performed by you at home!

Issue With the Pressure Switch

A common occurrence that causes the air compressor pressure relief valve to keep opening is an issue with the pressure switch.

Air compressors are designed to cut on and cut off at a particular pressure, which is regulated by the pressure switch. If the relief valve opens too often, it can be because the pressure switch is not reading the PSI correctly.

If there is too much air in the system, then problems occur during the compression process. Under-inflated air tanks will not supply enough weight at each stroke required for good cutting performance.

Fear not- fixing the pressure switch isn’t too complex.

How to Fix It

The best option is to replace the pressure switch. Consult a professional to ensure that a malfunctioning pressure switch is causing your air compressor pressure relief valve to keep opening. Air compressors have many electrical components and high pressure, which can be dangerous for a novice.

Once you’ve confirmed that the pressure switch is to blame, you can purchase a new one for around $55. Your air compressor technician will follow these steps to replace it:

  • Power down and unplug- Any electrical problems should be addressed immediately, using a circuit tester and/or multimeter. Make sure to turn off any power source that might cause electrocution.
  • Use Caution- Protective gloves are always a good idea when handling power tools. The wires underneath can be hot, so avoid touching them bare-handed.
  • Pull the pressure relief safety valve- We want to depressurize the tank completely.
  • Remove the tank pressure gauge- It can be unscrewed with a wrench.
  • Unscrew the pressure switch tube fittings- Then, remove the pressure switch tube.
  • Unscrew the pressure regulator assembly- This will disconnect from the old pressure switch.
  • Take off the pressure switch cap- Most air compressors have a black pressure switch cap. Take that off.
  • Remove the old pressure switch- Disconnect the black and green wires. Remove the safety valve. Unscrew the broken pressure switch.
  • Install the new pressure switch- Ensure that it has thread sealing tape or apply your own. Put the safety valve back on, and rewire the new switch.
  • Put the cap back on- Carefully reassemble your air compressor and turn it back on.

For a more detailed explanation, check out this video on how to replace it. Air compressors have different power ratings, so make sure the switch is appropriate for your machine before purchasing it!

Old or Damaged Spring

One of the leading causes of an air compressor pressure relief valve continuing to open is an old or damaged spring.

The springs of an air compressor pressure relief valve can degrade over time and become less stable. As a result, if there is any damage to the spring, the pressure relief valve could be opening prematurely (before the maximum pressure of the compressor is reached). 

The solution to an old or damaged spring is usually straightforward and quick to perform!

How to Fix It

The best way to treat an ineffective spring is to just replace the entire pressure relief valve. It’s pretty inexpensive (about $6), and chances are other parts of the valve are worn too.

To replace the air compressor relief valve, follow these steps:

  1. Unplug and turn off everything– For any troubleshooting, make sure to cut off any power source to the air compressor that might result in electrocution.
  2. Depressurize the air tank– Remove all of the air from the tank by unscrewing the drain underneath the machine. Once the hissing stops, the tank is empty.
  3. Remove the manifold cover– This will require a small screwdriver.
  4. Unscrew the pressure relief valve– This part will require a wrench for the first few turns, then you can use your hands.
  5. Install the new pressure relief valve– Screw in the new piece to the manifold first by hand, then tighten with a wrench. Make sure to follow the threads.
  6. Reassemble your air compressor– Put everything back together, plug it back in, and your problem should be solved!

Make sure to buy the correct pressure relief valve for your air compressor model. Each valve is designed to release at a maximum PSI specific to each model.

Air Intake Filter Is Dirty or Clogged

A dirty air intake filter can easily cause the air compressor pressure relief valve to keep opening.

Air intake filters are an integral part of the system that let air into a stationary or portable air compressor. They block dirt and contaminants from getting into the compressor, but if clogged, they can cause air compressor pressure relief valves to open in random intervals.

Cleaning or replacing dirty air intake filters can usually prevent this problem. Replacements cost around $50.

How to Fix It

Air compressors have a big metal cylinder that holds the oil and filters. Typically they’re easy to reach and quick to clean or replace.

Filters need to be cleaned every 245 hours of air compressor use. To clean the filter:

  • Open the access door to reveal the air intake and compressor side filters.
  • Unlatch the air intake side filter compartment and remove the filter. Tap the filter on a hard surface (as if you were smacking the dust out of a carpet) to help release dirt.
  • Re-insert the filter and close the compartment.

Filters need to be replaced every 490 hours of air compressor use. To replace the filter:

  • Open the access door to reveal the air intake and compressor side filters.
  • Unlatch the air intake side filter compartment and remove/discard the filter.
  • Insert the new filter and close the compartment.

If this doesn’t keep your pressure relief valve from popping open, you should contact the manufacturer of the machine for a service technician to help troubleshoot further.

How Do You Adjust a Pressure Relief Valve on an Air Compressor?

Sometimes, the maximum pressure on your machine is simply turned too low (this can occur if you bought a used air compressor). Turning this up manually can help prevent the pressure relief valve from continuing to open. However, proceed with caution and don’t exceed the machine’s maximum.

Make sure your machine is off and depressurized first. Then, you can try to adjust the valve yourself by following these few steps:

  • First, use a screwdriver to remove the top cap of the valve.
  • Locate the metal adjusting screw. Use your fingers to manually turn it clockwise in order to raise the maximum PSI.
  • Replace and tighten the top cap of the valve with your screwdriver when you are done adjusting. 

This will prevent your air compressor from tripping the pressure relief valve unexpectedly.

How Often Should A Safety Valve Be Replaced?

In most cases, the amount of time a safety valve will last is on the order of years. On average, you can expect to have to replace one every 24 to 36 months. It’s important to keep in mind, however, that your safety valve should be tested frequently to make sure it’s keeping things safe.

There are some situations where your safety valve could experience an accelerated aging process.

This can happen if you don’t perform regular maintenance on your air compressor. A safety valve can also experience premature failure if your air compressor is stored in an excessively hot environment for a long period of time.

So, How Often Should I Test My Safety Valve? 

At minimum, you should check your safety valve at least once a month. It is recommended, however, to check it every time it discharges.

This is important because every time the air compressor discharges, it leaves debris near the nozzle and the disc. So, make sure to keep this area clean to keep the safety valve in good operation.

Why Does My Air Compressor Cut On And Off Frequently?

When an air compressor turns on and off faster than it’s supposed to, that is known as short-cycling. Your air compressor may be short-cycling due to overheating, a bad compressor motor, or even a dirty air filter. 

If your air compressor won’t shut off, then check out this post here.

To Summarize

There are a few reasons your air compressor pressure relief valve keeps opening.

You may have a faulty switch or an old spring, but the most likely culprit is that you need to replace your dirty air filter. The good news (especially if you’ve been experiencing this for a while) is that it only costs $50 and will prevent further triggering of your safety valve.

If none of those seem like potential issues, consult with a professional technician who can troubleshoot further and make sure everything else checks out too!