You are working away, running your air tool, and all of the sudden the air compressor gets very loud. What’s going on?
There is a common compressor problem that is commonly associated with why an air compressor gets very loud. Understanding the basics of how the air compressor works will better help you understand the reason and the fix.
Smaller air compressors typically have piston type pumps. The majority of small air compressors have one piston inside a cylinder, housed inside the pump.
When the air compressor is running, the piston cycles. On the return stroke it pulls a bit of a vacuum in the pump head, and that allows the intake valve (commonly just a flap of spring metal) to open, and that allows air from outside the pump to be drawn in to the cylinder.
When the piston moves to its extend stroke, the increasing pressure in the cylinder pushes the intake valve closed, and opens the pressure valve to allows the air in the chamber to flow into the tank.
The two valves in question, the intake and pressure valve are commonly found on a valve plate. What separates the two is a valve plate gasket. the image below is of just one of them.
As noted, the pump gasket typically separates the high pressure and low pressure air flows. Over time, this gasket gets brittle. Compressor lubricating oil wicking onto the gasket can weaken it further. Eventually, a section of the gasket lets go, and air begins to cycle back and forth inside the pump.
Air Compressor Gets Very Loud
The result is the air compressor gets very loud, the air pressure may stop building in the tank, and your air compressor may run on and on until it overheats and goes off on thermal cut out.
If this is the scenario with your air compressor, odds are good that you will need to replace the gasket.
- first find a source for your gasket
- no source? Make one out of high heat gasket material
- consider replacing the valve plate at the same time (the gasket and plate may come as a set)
Replace the gasket and see if that resolves the issue. If not, or if you have a question, please comment below.