5 year old compressor, light duty use, less than 200 hours.
Now unit builds pressure, gauge of right side building fast, the one on the left slowly. When it reaches a certain pressure say 120, the unit suddenly blows off a burst of air.
After the burst of air, a weird electrical humm is heard for about 10 seconds, which stops.
An expert who has achieved level 3 by getting 1000 points
An expert that got 10 achievements.
An expert that got 5 achievements.
An expert whose answer got voted for 100 times.
Re: Hitachi EC12 Compressor- weird hum
The burst of air you hear as the compressor shuts off is the cylinder unloading so it will not have to restart against a high pressure load. If the unloader is electrical it would explain the hum that you hear. This could be a normal function.
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
Low pressure ususally caused by faulty reed valves /gaskets in the head. Easy to check. When compressor reaches highest pressure, check for air blowing out of the intake or no or very little suction. If the compressor has reached highest pressure and you still feel very good suction, suspect air leaking out of system. Check all fittngs with soapy water or shut off the compressor and listen carefully for air leaks. Repair as needed. If faulty reed valves, you can make them using feeler gauge material or purchase from www.toolpartsdirect.com
I have the same compressor with the same problem. I have temporarily eliminated the thermal reset with a piece of 12 gauge hard wire and it runs just fine. However, I do want to replace it before the warm weather come to the north. I tested the draw at 15.5 amps and the reset was a 17 amp. I am told by someone with superior electrical background that I need to install a 20 amp thermal reset in it's place. I have found that mine runs best when plugged directly into a 20 amp circuit and when using an extention cord I have a 10 guage cord that will carry the load needed to run the EC12. I have also changed to 100% synthetic oil.