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Why My Hitachi Air Compressor Won’t Build Pressure
- Compressor intake valve failing
- Compressor pump pressure valve failing
- Compressor gasket failure
- Compressor piston seal failure
- The tank check valve is compromised
Hitachi Air Compressor Intake Valve Failing
Hitachi Air Compressor Pump Pressure Valve Failing
If either the intake valve or pressure valve fails (breaks or fails to seat properly due to debris build-up) then your compressor will run all day and never build very much pressure in the compressor tank.
Hitachi Air Compressor Gasket Failure
Hitachi Air Compressor Piston Seal Failure
Hitachi Air Compressor Tank Check Valve is Compromised
Please visit our Why An Air Compressor Won’t Build Pressure & How To Fix A Compressor Not Building Pressure guide for detailed information on each reason, along with how to conduct the necessary checks! If you’re wondering why your air compressor won’t stop running, we also have a guide on this!
Reader Questions & Responses
Hitachi Air Compressor Won’t Build Pressure – Hitachi Air Compressor Troubleshooting Problems
I have a Hitachi 2 HP 4 Gallon Oil-Lubricated Air Compressor Model # EC12.
The motor sounds strong, but I’m getting hardly any air in my tanks. I check the oil and looked at the gasket and it seems to look ok. Air is coming out of the top of the motor. Don’t know if that is normal.
Hello Joseph. No, the air isn’t supposed to come out of the top of the motor. This symptom makes me think that you have a valve failure, and what may be happening (since air follows the path of least resistance) is that the air that’s being ingested by the compressor piston is being blown right back out of the same inlet port since it’s easier for the air to flow that way, than down past a check valve into the tank.
Why won’t your compressor build air pressure? There are a lot of reasons found on the troubleshooting page of this site that may also be a cause, though I suspect it’s the reed valve that is causing your compressor problems.
Is the reed valve the cylinder shape by the gauges that you can pull to release the air?
No, that’s the PRV, Joseph. The reed valves are located inside the intake hole (usually there is an intake filter screwed into the intake port) and they control the air in and stop the air out so that the air can be forced into the tank.
If you have any questions about Hitachi air compressor not building pressure, please leave a comment below, with a photo if applicable, so that someone can help you!