Air Compressor Can’t Build or Maintain Pressure?
When your compressed air system fails to provide sufficient pressure, whether that be for auto body painting and detailing or powering a city-wide transit network, your organization suffers. Knowing how to troubleshoot to pinpoint your system’s failure is vital to get any system back to optimal condition.
1. CONDUCT A PUMP UP TEST.
A Pump Up Test can provide awareness into your compressed air system’s ability to build pressure. To conduct the test, first empty the air tank. Then, close the service valve at discharge, and record the amount of time it takes for your compressor to achieve your desired PSI from 0. Then use our Pump Up Calculator to see how much time it should have taken.
If your system is taking longer to pump up than the calculations show it should take, then you know for certain you have an issue that needs to be addressed, and therefore move down this list.
2. KEEP FILTERS CLEAN.
First, check your air inlet filter. To do so, loosen the wingnut, remove the housing cover, and inspect the filter. Ensure it is clean and clear of debris and buildup. Conduct periodic maintenance to ensure all the filters on your air compressor are clean. Replace filters as often as recommended or necessary based on your environment.
3. ASSESS AIR DEMAND AND SCREEN FOR LEAKS.
The initial, and simplest steps, are confirming your air demand settings are adjusted to the proper level and checking for potential leaks. Leaks are a common culprit. In fact, according to experts at Efficient Plant, facilities with no effective leak management protocol lose an average of 30% to 50% of their total compressed air production to leaks.
Survey your air system, check the all pipe connections and repair any leaks that you discover.
4. CHECK ALL OF YOUR COMPRESSED AIR SYSTEM VALVES.
The next step in troubleshooting a compressed air system that won’t build the necessary pressure should be examining your machine’s valves. Make sure the inlet valve is able to fully open and the drain valve at the bottom of the air tank is sealed tightly.
You can also assess oil passthrough by opening your drain valve and looking for oily residue. While every oil or lubricant-based compressed air system will experience a natural level of oil carryover, the amount of oil that appears in the air tank should be minimal. High levels of oil carryover will prevent a compressor’s ability to build pressure. After checking the inlet and drain valves, make sure the safety valve is not leaking or experiencing any problems.
The most common reason behind a reciprocating compressor’s inability to reach sufficient pressure is a defective reed valve. The reed valve can be found on the top of each cylinder. To replace the valve, loosen the cap screws, remove, disassemble, replace the reed valves and gaskets and reattach the head plates to the cylinder.
5. EVALUATE BELT CONDITION.
If your compressor operates on a belt-drive, a belt malfunction may be the culprit for low pressure. To check the belt, make sure your machine is turned off and the power disconnected. Remove the rear section of the belt guard. Loosen the motor mounting bolts in order to tighten or, if necessary, replace the belt. Slide the motor in the direction of the pump, gently remove the belt from its pulleys, install a new belt(s), and return the motor to its proper position. Tighten the motor mounting bolts and adjust the belt tension as needed. Reinstall the belt guard.
6. INSPECT PUMP RINGS.
Effective pump rings seal the air in the cylinders, prevent excess oil from passing downstream, and are critical in ensuring an air compressor’s ability to build pressure — if pump rings are worn, the pump will be unable to effectively compress air which can greatly reduce the volume of air the pump can produce. If this is the case, rebuild or replace the pump.
If both the pump and the pump rings seem to be operating correctly, check the valve plates to ensure they are sealing properly.
7. ASSESS MOTOR CAPACITORS.
If the capacitors in your compressed air system aren’t functioning as they should, the motor may not be receiving sufficient power to start the single-phase motor. Issues with motor capacitors inhibit a machine from coming up to normal operating speed. On three-phase motors, a bad winding or phase imbalance may cause the compressor’s breakers (fuses) to trip. To address problems with motor capacitors, it’s best to partner with a certified electrician.
8. EXAMINE YOUR AIR/OIL SEPARATOR.
On oil flooded rotary compressors, after checking oil levels, assess the pressure drop across the air/oil separator. If the air/oil separator is fouled, plugged or damaged, it could be preventing the successful separation of oil and air within the compressor, thus hindering the machine’s ability to reach the cut-out pressure level and increasing operating costs. When necessary, replace the air/oil separator.
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