Hey! This site is reader-supported and we earn commissions if you purchase products from retailers after clicking on a link from our site. When an air compressor will not stop it could signal a problem with how the air compressor is pumping air into the compressor air tank. Show
Or, when an air compressor will not stop, it could also signal a major safety concern, and should be addressed immediately, before using the compressor again. Compressor pumps up past cut outIf an air compressor runs, pumps air into the air tank, the tank pressure reaches the normal cut out pressure setting level, and the compressor continues to run and the pressure continues to build, this is a real problem! Eventually the PRV will let go, and the tank pressure should vent. The compressor will still run at this point though, and if it isn’t being monitored, it could run itself to death. PRV doesn’t let goThe safety backup for the air compressor pressure switch is the PRV, the pressure relief valve. The air compressor can pump air pressure into the tank to a level higher than the compressor is supposed to. If that pressure gets too high, there could be a major failure of a part, and if that compressor part is the tank, well, the results wouldn’t be good. The PRV is factory set to a pressure higher than the cut out pressure of the pressure switch. If the pressure switch does not shut the compressor down at the normal cut out pressure setting, when the tank pressure reaches the PRV set point, the PRV opens and vents the air. If the PRV fails, my friend, you have a real serious problem! If the compressor pumps air pressure past the normal cut out pressure setting, my advice is to not use the compressor until this is fixed. Your compressor pressure switch should shut the compressor offA typical pressure switch on your air compressor might be the Condor brand, similar to the one in the photo.  It is the compressor pressure switch that is supposed to shut the air compressor off when the tank pressure reaches the cut out pressure level. That pressure cut out level may be in the 100 PSI through to 175 PSI level, depending on the brand and size of your air compressor. The pressure switch reacts to the pressure in the tank and when that tank pressure reaches the cut out pressure setting the pressure switch trips to off, the power to the motor is cut, and the compressor stops. That is, if the pressure switch is working. If the compressor continues to run past the cut out pressure setting then it is a pretty good bet that the pressure switch has failed. As far as I’m concerned, it is time for you to get a new compressor switch. Replace the pressure switchI know that finding after market parts for air compressors is hard, as so few of the stores that sell air compressors stock a comprehensive list of spares for the dozens of brands that they sell, and have sold, over the years. When you are looking for a replacement pressure switch, as long as the replacement switch fits the mounting on your air compressor, if it connects properly to the existing unloader valve – or has an internal unloader valve – is the same voltage range as the existing and has the same cut in cut out pressure settings (or is adjustable) then you can use it. It is not necessary to replace a pressure switch with exactly the same make and model. That is, unless your air compressor is under warranty. Using an off-brand part may void the warranty. But on the other hand, if the air compressor is under warranty, see the store where you bought it and give them the problem of replacing the switch. 🙂 That should take care of the case when an air compressor builds air pressure up past the cut out, and the compressor runs until the PRV lets go. Air compressor will not stop – stillOK, there is another scenario where the air compressor will not stop and just keeps on running. That is when the air compressor tank pressure will only pump up to a level that is below the pressure switch cut out setting. That is to say, your air compressor starts OK – probably from an empty tank when you go to reuse it again, but instead of pumping up to the 100 – 175 PSI expected, the pressure in the tank only gets to 20 PSI, or 30 PSI or 80 PSI and levels out there. Even though the air compressor continues to run, the tank pressure refuses to increase. Not correcting this problem can lead to self-destruction, or at the very least, overheating of your air compressor. There are a number of reasons why this happens. Failures on an air compressor that could cause this include:
… to name just a few. All of these will be discussed as a separate page linked under the Fixing Compressor Problems link. More pages on this subject include:
Most of us have air compressors in our garage. They are handy for airing up tires, blowing dust out of crevices when we are detailing our rides and for running pneumatic tools. It’s always perplexing when you turn it on, only to realize several minutes later that the compressor hasn’t built up pressure and kicked off. Is it getting over-pressured? Is it going to explode? Is it repairable? Whether you have a small pancake compressor or a large, industrial one, the basics of how these compressors work are the same. Here is a quick troubleshooting list to help you diagnose why your compressor hasn’t turned off. Important Information On Pressure SwitchesAll compressors with a tank have a pressure switch built into them. These pressure switches pay attention to two different pressures: at what point the compressor motor should turn on, and at what point it should turn off. Usually, there is a set distance between the cut-in pressure and the cut-out pressure, but the overall range can be adjusted higher or lower by using a screwdriver. Pressure switches are critical as they help provide safety both to those around the air compressor as well as to the components of the compressor itself. If your compressor is not turning off, it is likely that it isn’t reaching the cut-out pressure. Here are some top suspects for troubleshooting your compressor. #1 The Drain Valve Is OpenAir compressors collect the water from the atmosphere. This water pools in the bottom of the compressor tank where it can rust the steel of the tank, weakening the walls. A high-pressure tank with weak, rusted walls is a deadly combination that can lead to an explosion, so manufacturers insert a drain valve on the bottom to relieve the standing water and prevent rust. Most people open the valve when they are done using their compressor and leave it open until the next time they put it in operation. It is very likely that the drain valve is open and leaking air. #2 The Gauge Is BrokenSometimes gauges break. If the gauge is not moving at all, then it is possible that the gauge is no longer functioning. Even if it is moving, there is still a chance that you have a broken indicator, but it is less likely. Depending on your pressure switch, it may need a working compressor gauge to measure the air tank pressure levels. If it appears that the gauge is broken, you can try to replace it. Most pressure switches measure the air inside the tank independently of the gauge. If that is your case, then a non-functioning gauge will not affect the pressure shut off switch. #3 There is a LeakIf the drain valve isn’t open, but it still won’t build pressure, then you are probably still dealing with a leak, just in a different part of the unit. Try unplugging all hoses from it. It could be that you have a hose, connector or power tool that is leaking air. Blower nozzles and paint guns can be triggered open and leak large volumes of air. By removing the hose, you are able to isolate those variables.
The primary seal between the compressor head and the tank can be a culprit. This seal often only demonstrates the leak at pressures above 80 PSI. Because it requires higher pressure to find the hole, you may need to search quickly before the pressure bleeds down again. If you suspect a leak like this, you should reach out to your compressor manufacturer for a rebuild kit. #4 Dirty Intake FilterAnother potential problem is that the air intake filter has become clogged with sawdust and other debris, restricting the airflow that is coming into the compressor. To combat this, use your owner’s manual to locate and clean the compressor intake. Sometimes there is a large, external air filter to remove and clean. More than likely, the filter is small and hidden inside a small port. #5 The Piston Is Becoming WornOver time, your compressor piston that creates the pressure will likely wear grooves both in itself and in the walls of the compressor. If you use your compressor heavily, it is likely that you will notice it requires more and more time to build the same amount of pressure. This inefficiency is due to the wear in the cylinder walls that allows air to escape past the piston and reduces your compressor’s effectiveness. This is a harder problem to diagnose, and is mostly restricted to those who know that their compressor is older and that it is likely suffering from “old age”. Unlike an engine, these compressors are not typically rebuildable, and you will have to invest in a new compressor. #6 The Safety Relief Valve is Stuck OpenThe pressure relief valve (PRV) is a safety mechanism that releases pressure in the event that the pressure switch does not turn off at the proper time and over-inflates the compressor tank. The PRV is a critical component that prevents an explosion. If your PRV is stuck open, then it may be rusted into place if it stays open and leaks pressure than it needs to be replaced before you attempt to use the compressor again. #7 The Pressure Switch Is Broken (or not adjusted properly)If the compressor inflates to the point that the PRV activates and bleeds down pressure than it is possible that the pressure switch is adjusted too high. Try Switches can also be broken. If adjusting your switch does not fix the problem, you may want to try replacing it as a last resort. There are some guides on how to test your switch with an ohm meter. It can be frustrating to deal with a compressor that does not build pressure or a compressor that does not turn off. If you have the This guide can hopefully help you find the answer more quickly can get back to work. Repair Or Replace?The biggest challenge in repairing your compressor will be finding the correct replacement parts. If you can find parts, the compressor itself is a very simple machine and relatively easy to repair. Always follow manufacturer’s recommendations and make sure the compressor is unplugged and drained before beginning any repair work. If you are unable to find replacement parts, you may have to invest in a new compressor. Every year, new models are release, and sites like Tool Tally keep an updated list of the best air compressors to make shopping easy. |
Why wont my air compressor turn off
Related Posts
Copyright © 2024 SignalDuo Inc.
