If new safety valve leaks remove cylinder head inspect and clean reed valve assembly.
Air compressor valve leaking.
Safety relief valve not functioning properly.
Replace the safety valve if it leaks air constantly.
This video goes over a few main reasons why your air compressor pressure switch or unloader is leaking while the compressor is running or when it shuts off.
Well if air continuously leaks out of the unloader valve then the compressor tank is emptying and the compressor needs to restart to replenish the air in the tank to get back up to cut out pressure so it can stop on its own.
With the compressor off the unloader valve should not be leaking any air at all after the unloading process a second or two has completed.
Leaky gasket high pressure inlet valve.
My little 2 gal.
The valve on the outside of the pressure switch may look something like the one in the image.
Unloader valve is leaking air.
The unloader valve is only leaking when the compressor is running.
When the air compressor reaches the normal cut out pressure and stops but you notice while the air compressor is off that air is leaking out of a valve attached to or perhaps inside of the air compressor pressure switch.
If air leaks out the unloader when the pump stops replace the check valve because the check valve leaks air back towards the unloader.
The safety valve pops open to relieve excessive air pressure if the pressure switch fails to shut off the air compressor at the cut out pressure setting.
If the air is leaking from the unloader valve then see the page under fixing compressor problems about air continuously leaking from the unloader valve for.
I had a look at the check valve and all is good.
Air continuously leaks out of the unloader valve on your air compressor and this is a problem.
Remove and install new safety relief valve.
The unloader valve is leaking air when the compressor is running.
If air is leaking from the unloader valve when the air compressor is stopped that points to a problem with the compressor tank check valve not seating properly or its failure.
Air leaking from inter stage safety relief valve when compressor is pumping.