LF10A-4H air valve stays open.

by Raul
(Guatemala City, Guatemala)

LF10A-4H

LF10A-4H

The air valve (LEFOO model LF10A-4H) that is at the end of the copper tube stays open all the time. I heard the "hissing" of air escaping there so I did not let the pressure build up to the maximum limit.


So, Should'nt this little valve be closed while the motor is building the pressure?
If so, How do I fix it?
Regards, Raul

Comments for LF10A-4H air valve stays open.

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Jul 27, 2018
Lefoo and check valve
by: Bill

In your photo, I think it's the item on the left, the black component.

If that's not it, typically, the check valve inserts into or is the first item attached to the tank where the air line from the pump reaches the tank.

Raul, EVERY question you've asked so far is already covered extensively on the pages of this site. Please use the sitemap page and the troubleshooting page to read all of the pages that either apply to your original question, or as new questions arise, have to do with your new questions.

The information imparted in this thread is hugely redundant as it's already on this site in much greater detail for your use.

This thread is now closed. No further comments will be posted. Thank you.

Jul 26, 2018
Check valve
by: Raul

Where is the check valve located at?

Jul 26, 2018
Not the pressure switch
by: Doug in s.d.ca

if this is true:

Quote: "So I set the start/shut off to where it shuts off. But when it shuts off THAT AIR VALVE STAYS OPEN and the tank empties up.If I unplug the motor before it reaches the shut off pressure that AIR VALVE STAYS CLOSED." End quote

That's a bad check valve.

Jul 24, 2018
I'll bend the tab..
by: Raul

Since I made my mind to buy a new one I will bend the tab to see what happens.

Jul 24, 2018
I'll get a new one.
by: Raul

I will get a new pressure switch.
I just hate to drive downtown and find out who has a replacement. About five miles in this horrible latin american trafic.
Here is not like in Texas that you can call and find out if they have one in stock. Or check their website.
This one that failed I got it thru Ebay.

Thanks for taking time to answer my question.

Best regards.

Jul 24, 2018
LF10A-4H
by: Bill

"So I set the start/shut off to where it shuts off." Are you saying you adjusted the pressure switch setting? If so, what is the new cut in and cut out pressure settings?

The unloader valve is supposed to be open, dumping air over the piston, when the compressor is stopped.

When the compressor starts, the unloader valve then closes as the pressure switch trips to allow power to the motor, and the unloader should stay closed, so that all the air being produced is sent into the tank.

If the unloader valve is open when the compressor is running, either the pressure switch or the unloader valve itself has failed.

Don't bend the tab. Buy a new switch and unloader valve and replace the one that has failed, if in fact it is not working the way it is supposed to.

Jul 24, 2018
I don't know....
by: Raul

So I set the start/shut off to where it shuts off.

But when it shuts off THAT AIR VALVE STAYS OPEN and the tank empties up.

If I unplug the motor before it reaches the shut off pressure that AIR VALVE STAYS CLOSED.

Could I bend that little tab so it stays closed?

Jul 24, 2018
Well, I kind'a jumped the gun......
by: Raul

So today I let the motor build up the pressure to the cut-off (or close to it) and that valve closed.

But, if I turn the lever from AUTO to OFF it opens again. If I unplug the motor, it stay closed....

Maybe because fooled with setting screws.

So now I have to do the settings and see what happens.

Thanks for your answers..

Jul 24, 2018
LF10A-4H
by: Bill

Raul, I take it, then, that the air pressure in the tank never reaches the cut out pressure level to allow the compressor to stop?

While it is a bit hard to see in your photo (thanks for that) there is a lever on the side of the switch that is supposed to open and close the valve (unloader) on the side of the switch.

If the lever is not moving to open and close that valve as the compressor cycles, that normally means that the pressure switch itself is not working properly, and it's probably time to replace the switch with one that works.

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