Re: hitachi compressor motor runs but it will not fill...
Hi your problem could lie in one of two areas
1/your unloader valve is stuck in the unload position
2/ your valves in the compressor pump head have broken and need renewal
hope that this is helpfull any further do not hesitate to contact
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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
Air leaking from tank back into compessor is indication that in-tank check valve is leaking. This condition will stress motor when trying to start. Test : With air in tank, unplug compressor from outlet and remove hose from compressor at checkvalve and test for leak (soapy water). If leaking drain air and remove checkvalve. Examine checkvalve for debris under seat (resurface seat or replace valve). Parts are at www.toolpartsdirect.com Good luck
you are supposed to use the unloader valve to start. when air is in tank the starter motor is not only turning the motor but also trying to compress air. this very hard on the whole unit. the unloader valve should have what looks like a loose lever. lift the lever and it pulls the attached rod. after motor starts and runs put back to rest position
disconnect line out from the compressor, run unit for about 5 to 10 min. if no problem. I would say that your tank valve is in wide open. replace it. the valve must close on ever down stoke so air don't feed back. this valve is screwed into your tank at lines end- good luck
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.
The regulator sounds like it is cranked closed. Try slowly operating the adjusting knob in the opposite direction. As the valve moves, you should see the pressure rise on your gauge (it probably does work).
Hope this helps....now go make something!
Best regards, --W/D--
The start valve gives your motor a running start before the motor begins to load as the pressure increases from an empty tank. The motor strain is more profound when there is pressure in the tank. If you plug the valve, the motor will instantly encounter a heavy load because it has to force air into a partially filled tank. This extra load without the valve will shorten the life of the capacitors and motor windings. There could be two problems with your unit that can revealed by test. What actually closes the valve is a certain volume of air produced by the compressor. If the compressor is not pumping to full efficiency or there are leaks in the discharge hose the valve will not close. Or the valve is faulty. With an empty tank, plug the valve and run compressor and test airline for leaks with soapy water. If no leaks, empty tank of air and restart compressor and take note of the amount of time it takes to fill the tanks to shut off. If it takes an unusually long time to fill, then the compressor probably has valve problems causing low air volume. If the compressor fills to shut off in a short time frame as compared to a similar model then replace the valve. Leaking valves in the head will also cause the pump and discharge tube to run very hot. Parts are available at www.toolpartsdirect.com Good luck with your repair.