Question about Hitachi EC12 Portable Electric 2hp Air Compressor, Oil Lubricated

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Air tank leaks along the weld

I turned on my Hitachi EC 12 today and air began leaking along the weld of the upper tank. Can this be repaired with a spot weld?

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Posted on Jul 27, 2009


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2 Answers

How can i fix my ec12 hitachi electric air compressor

This problem is caused by either the starter capacitor or the in-tank check valve. Ez to check. With no air in tank, start compressor; if motor hums or has difficulty suspect capacitor. If motor starts, partially fill tank and unplug the power. Check for air leaking at the pressure switch or air coming out of the air inlet (remove the air filter). If air leaking, replace check valve. If no air leaking, again let out all the from the tank and connect power. Allow the compressor to fill and shut-off. After the compressor fills, again listen for air leaking from the pressure switch unloader valve. If air continues to leak from unloader, replace the check valve. Good luck

Jun 11, 2015 | Hitachi EC12 Portable Electric 2hp Air...

1 Answer

8 gal losing air, checked all connections, no leaking, where else to check ?

look for a small leak around the welded seams on the tank as well as all the welds on fittings. When there is air in the tank, shoot some soapy water on it like you were looking for a leak in a tire to find small leaks.

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Hitachi Ec 119 compressor will not build pressure beyond 25 pounds; no air is heard leaking after I power down the machine. Is it likely the check valve or pressure switch?

If your compressor keeps running and only builds to 25psi, I would suspect the reed valves, head gaskets or a leak. With the compressor running spray soapy water on all fittings, around the head area and tank components. If no leak is found, remove the air filter and feel for suction at the intake(make sure head is not too hot). If you feel good suction at first then suction is lost after reaching 25 psi, most likely reeds or gaskets (with bad reed valves, sometimes you will actually feel air blowing out of the intake). Good luck

Oct 15, 2011 | Hitachi EC119SA Twin-Stack Air Compressor...

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Hi! I have a compressor that leaks air on the bottom of the tank. I neglected to drain it during it's life time, so it got rusty at one spot and, when I pump air, it leaks. Is it repairable? Could any...

Due to the explosive ability of compressed air, I would not recommend any repairs to a compressor tank. It is possible to weld a patch on the rusty spot but the heat would weaken the rest of the tank and you could face a very dangerous explosion if the tank should fail at another spot. As an authorized service center, if I have to replace an air tank I have to drill holes in the old tank to render it useless and safe. Save yourself a huge nightmare and buy a new compressor.

Nov 08, 2010 | Air Tools & Compressors

2 Answers

My ec 12 compressor will run and shut off around 125 psi and then it bleeds off untill it turns on around 80 psi Ive replace the pressure switch and its still doing this Why?

It souds like a sticky "non return valve". See the fix below.
The non return valve is the chrome part with a hex cap adjacent to the upper tank. Remove the cap and make sure the piston moves freely. Slight resistance is ok, but if it sticks your compressor willl continually blow off air.

The check valve or "non return valve", as listed in the Hitachi parts manual is definitely the culprit here, but there is an alternative solution to replacing the entire valve that was actually suggested to me by a Hitachi Tech when I stopped by my local service center to pick up a new non return valve. Obviously, the rubber piston swells and sticks to the point that the spring under the piston can't over come the friction. I removed the piston and carefully reduced its diameter, by hand, with varying grades of wet or dry paper and it now operates perfectly. If one is uncomfortable with such a repair, at least keep it in mind for a quick jobsite fix. I have now been running my repaired compressor for several months without issue.

Jun 25, 2010 | Hitachi EC12 Portable Electric 2hp Air...

1 Answer

Hitachi EC 12 Air Compressor does not keep pressure

to repair this problem (a) the pressure switch is not working,(b) check valve or non return valve sticking(stripe down repair and refit)

Sep 28, 2009 | Hitachi EC12 Portable Electric 2hp Air...

2 Answers


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

Sep 23, 2009 | Hitachi EC12 Portable Electric 2hp Air...

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