Hitachi EC89 air compressor just hums and reset button pops..doesn't turn on at all..

david mcclellan

• 530 Answers
• Posted on Aug 12, 2009

SOURCE: Hitachi twin stack problem.

You stated that the compressor started up fine. I'll assume it reached it's max psi then cut out. Then upon reaching it's cut-in psi the motor ran slowly for a few seconds, then kicked off. I also assume you mean check valve when you refer to the non return valve.
If this sounds about right then. The first thing I would do is bleed out all the air from both the tank and the pump supply line leading from the pump head to the tank's check valve. You can do this by simply loosening the fitting that attaches the line at the head or the check valve. Once done try running the compressor again.
The purpose of this is to check the unloader valve. This valve bleeds off the pressure that remains in the compression cylinder and the supply line up to the check valve. When functioning normaly it will bleed off this pressure once the motor shuts off. If it is not working correctly then when your compressor starts back up (once it is already been filled) the piston will be working against a psi close to the max psi.

If the problem reoccurs only after the compressor has reached it's max psi, then the unloader valve is most likely the problem. If however it will not start up at all even after a complete bleed then it has to be something internal to the pump and\or motor.

Please try this and let me know (or repost) your findings.
If it's the unloader valve I should be able to explain how to repair this valve.
Good luck.

Testimonial: "Good info"

SOURCE: keeps blowing the breaker... only 6 months old

This compressor is small however like other brands in this size range draw 13 - 15 amps. Thats quite a bit of power. The compressor has a thermal breaker that will begin to trip if compressor is hot. I am assuming that the breaker that is tripping is the one on the compessor. I have seen many hitachi breakers fail. Easy to replace with generic 20 amp, cost about $10. Before you replace anything, check amp draw with meter, if within specs try to determine what is causing heat.
example:
cycling too many times per hour (check manual for recommended)
low power due to weak circuit or extension cord
using generator for powering compressor (not recommended)
using low quality oil (use synthetic if hot climate)
air leaking from intank checkvalve back to pump
If no reason to overheat then replace breaker on compressor to 20 amp but watch for overheating. Good luck

SOURCE: Hitachi EC 12 2hp Air Compressor. Just get a

Hitachi EC12 Air Compressor Parts : MASTERTOOLREPAIR.COM

Here is a site that says:
1. Are the capacitors good? (They get the motor going).
2. If they are, replace the stator, ($245)

If you don't find a good solution there, I would try taking it to a local motor rebuilder.
Gary

SOURCE: When I turn on the compressor, it hums, but the

sounds like it has ran low on oil and has siezed,sorry man it's probaly toast.

Brad

• 425 Answers
• Posted on May 18, 2012

SOURCE: I have a 33 gal craftsman compressor when I turn on the relay switch hums but the motor doesn't spin?

I would check the capacitor since it appears that the motor is not locked up. Here is a how to on testing capacitors;


how-to-check-capacitor