About Us    Contact Us

Hitachi Air Compressor Won’t Start – Help & Support

Published Categorized as Air Compressor Won't Start, Hitachi No Comments on Hitachi Air Compressor Won’t Start – Help & Support

There have been many Hitachi compressor users querying why their Hitachi air compressor not turning on and other questions along these lines. Do you also have Hitachi air compressor problems?

Well, this article will present some of the main reasons why this may be happening and provide Hitachi air compressor troubleshooting suggestions to resolve those issues, along with existing reader problems.

Table of Contents

Reasons Why Your Hitachi Air Compressor Won’t Turn On

The main reasons why your Hitachi air compressor not turning on are likely to be due to any of the following reasons, and accompanied with them are some tips on what to do:

  • Power issue – it’s likely that you’re underpowering the compressor, therefore, you should avoid using extension cords and power bars.
  • Fuse or breaker blowscircuit breakers will trip off when a power surge blows their fuses. If the fuses are faulty, you will likely need to replace the fuses.
  • Faulty pressure switch – unplug the Hitachi compressor from the electrical outlet before opening the drain valve releasing the air from the tank down to zero and then closing the drain.
  • Faulty thermal overload switch – check the thermal overload switch to ensure it is working correctly.
  • Faulty unloader valve – check the unloader valve, if it’s faulty, the pressure switch may not work as it should.
  • Insufficient oil – check the oil level, and inspect the pump area for any potential leaks.

Please visit our Air Compressor Won’t Start – Ways to Fix Air Compressor Won’t Turn On Problems guide for more detailed Hitachi air compressor troubleshooting & fixes!

Reader Questions & Responses

EC12 Hitachi Air Compressor Will Not Start – Hitachi Compressor Troubleshooting


EC12 fills to 125, stops but bleeds off to start pressure but then the compressor won’t start-up.

This can happen at different times, works great other times. I think it is the non-return valve (item 53)


Hitachi EC 12 air compressor
Hitachi EC 12 air compressor plumbers


Yeah, that’s what we usually call a check valve. Given that this is an intermittent problem, there’s probably some crud inside near the seat.

You can probably take it out and disassemble, clean, re-assemble, and reinstall it (maybe even just blow it out if you want to try that first). And do be sure the tank is not under pressure when you do the removal!

If that doesn’t do it, then you can replace it.

Have fun.

Hitachi EC12 Air Compressor Not Starting – Hitachi Air Compressor Problems


Hi, this is Peter.

I have a Hitachi EC12 twin tank. It’s bogging down not running.

I checked the capacitor and replaced it with a capacitor made by Packard, model Prcf40 40ufd: 5. 440vac 60/50hz from the local a/c store.

The original is made by Facon mod 7G73400P7B 40 uF: 5 SH. 450 Vac cl.D 50Hz.

But it doesn’t work either.

Do you think I should install the OMD so it can work?

The capacitor from Hitachi is so expensive $38 each or do you think just keep the money and buy a new compressor?

It is ten years old. I want to make sure it works before ordering the capacitors.

Thank you


Peter, are you sure it is the cap? How did you test it, please?

When you acquired the replacement, did you take the old one and ask the store person to give you the exact replacement?

If you don’t have the same specs on the replacement capacitor, or if you haven’t checked the old cap (you say you did, but how?) then it may not even be the cap that’s at fault. Need a bit more info on that? Right here.

At what pressure is your compressor bogging down? Is it at the same pressure every time, or does that vary? What is the circuit amperage? Are you using an extension cord? (Don’t) With the intake filter removed, do you still get the same issue?

There are a host of things, including a cap problem, that can cause a compressor to bog down.

If you have any questions regarding the Hitachi air compressor won’t turn on, please leave a comment below, with a photo if applicable, so that someone can help you!

By Aidan Weeks

A passionate Mechanical Engineer with endless enthusiasm for fluid power - building off the back of over 18 years of high quality contribution and discussion stimulated by Bill Wade here at About Air Compressors. With both practical and theoretical experience in pneumatics and hydraulics, I'm putting my knowledge to work - and working my grey-matter through my research, assistance and publishing work here at About Air Compressors. Feel free to reach out any time! P.S. A HUGE shout out to Doug who really offers such great value to all visitors to About Air Compressors - once again, feeling like I'm standing on the shoulders of GIANTS by getting to work alongside such a great community

Notify of
Inline Feedbacks
View all comments