20 Most Recent Hitachi EC12 Portable Electric 2hp Air Compressor, Oil Lubricated - Page 3 Questions & Answers

No, this would be the pressure switch. One pipe or small line to the tank, with power cord coming in and cord to motor. It is adjustable so try reducing tension on the spring first. If still no change replace pressure switch.

Make sure the power cord is plugged into an adequate extension cord if one must be used. Never less than 12 gauge wire.The start/run capacitor may need to be replaced.. If there are any ball check type valves, make sure they are not worn or sticking. they would be on the output of the compressor head itself.

Hello. here is a link to a free downloadable owner manual and parts list. http://www.hitachi-koki.com/manual_view_export/pdf_manual_view.do?implementationWorkNumber=312&partsCode=C99128411&model=EC10SB(SL)+/+EC12&marketSeq=4

what type of air compressor you have,since when you maintained it

I have read that a thin or long extension cable can cause this. But you can also circuit breaker that plugs into the line before the device. And I would think the breaker on the main board would be enough protection.

http://www.hitachipowertools.ca/upload/fmproduct_filee/EC12__OM_6334.pdf

the problem is in the check valve where air enters the tank.when leaking it lets air pressure up to the air piston causing the motor to stall upon restart.replace check valve.average cost of part 15 to 30 dollars.simple fix

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

After removing all components to expose the armature, I used a three arm puller to push the shaft out. You could also take the pump to machine shop and have them push it out (have the new shaft ready for install while there). But before you go thru all the trouble, try polishing the journal with very fine emory or wet dry metal sandpaper cut into strips. I know the journal may look bad but after you remove the metal deposited there by the soft rod, it may clean up enough to work. Sand only enough to remove the aluminum. Polish with very fine paper. The rod only costs about twelve bucks and you will be surprised how well it works. Good luck.

air compressor, synthetic oil, SAE 5W50



http://www.ereplacementparts.com/

can get manual from where you purchased the unit if purchased new http://www.toolpartsdirect.com/cgi-bin/schematic.cgi/hitachi/EC12

here you will find a parts manual

DO NOT FILL to the plug threads on this compressor!!! The dipstick has a mark and it is very near the end of the stick. Any more questions please email or repost.Tim

Yes it has an unloader valve on the rear of the pressure switch. Replacement will depend on the model of the power switch, they used roughly three different models on this compressor.Tim

If you had shrapnel in the top of the piston, you probably have pieces in the wall and the rings are probably bad. I would tear it down look at everything from the top down to the cylinder or block. if there are gouges in the wall it will need to be honed if they are not real bad, otherwise replace it. Certainly replace the rings and inspect the piston as well. If you have the Italian pump it would be worth fixing, if not it may get costly. Also inspect all your gaskets and valves. You may also have shrapnel in your infeed tube which may get to the Non-Return valve and cause it to stick open and bleed off pressure. If you can post more details I maybe able to help you further.Tim

they usually have a slash on the stick.

This is a stab in the dark.....but have you emptied the condensation out of the tank? It may reach max pressure....but have little air compressed inside the tanks. Just a guess.

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 it's not adviseable to run without the thermal reset for an extended time. 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 with no extention cord. But, when using an extention cord, I have a 10 guage cord that will carry the load needed to run the EC12. I also have changed to 100% synthetic oil.

Over time water and debris will enter the regulator and cause problems. Easy to fix however. Drain air from tank and turn pressure control knob out to relieve pressure on the internal spring. Open the regulator and clean and lube the internal parts (use silicone paste lube on rubber parts). Some regulators have a small nut on the rear that should be remove to clean small piston. If parts are rusted beyond usefulness, replace with generic regulator that will fit into space. Good luck