Rolair Air Compressor Repair

On todays repair diary we have a 5L rolair compressor that was leaking a large amount of air. Originally it was suspected to have a faulty unloader valve on the pressure switch. After receiving the new pressure valve, the constant air leak stopped, however the unloader valve was purging the tank pressure when the compressor was off. This prompted me to look at the check valve which prevents the tank pressure from exiting the unloader valve when the compressor is off. Sure enough this was full of corrosion and cleaning this solved the problem!