Question about Air Tools & Compressors

1 Answer

My compressor loads but doesnt unload ,the thing is we installed a new unloader valve and changed all blow down solenoid valves. what may be the problem?

Posted by on


1 Answer

  • Level 1:

    An expert who has achieved level 1.


    An expert that got 5 achievements.


    An expert whose answer got voted for 20 times.

    Night Owl:

    An expert who has answered 10 or more questions between 12 midnight and 6am on the same day.

  • Contributor
  • 40 Answers

Check unloader solenoid valve, always energize.

Posted on Aug 09, 2010


1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

I got an Ingersol rand Rottary Compressor Model# PX6683U06083 Compressor it releases coolant out of the air intake I belive it was running backwards for a short while now it is rotating the right way, can...

If this type of compressor is run for any length of time in the wrong direction you will do damage for sure now if this unit is shut down while it is loaded (producing air) it will push lubricant out of the inlet filter most of the time people hit the emergency stop button to shut it done which is wrong the compressor should be unloaded first which when unloaded the inlet valve will be closed which then the compressor will be running unloaded and can now be shut down using the off button or switch not sure which one you have other reasons why this could happen failing load/unload solenoid usually the vent is plugged or bad minimum pressure check valve

Feb 27, 2012 | Ingersoll Rand Air Tools & Compressors

2 Answers

I have a vt631401aj campbell hausfeld compressor. when it builds pressure to 135 psi, the compressor shuts down and immediatly starts dumping air until it goes down to 90 psi. It then stops dumping the...

John: I had a similar problem with a brand new CH-made compressor. The problem was not with the unloader valve, but with the check valve located where the air from the pump enters the tank. The check valve was not seating correctly due to brass filings from manufacture. The defective check valve was allowing air to escape back the wrong way from the tank to the pressure switch and through the unloader valve. This backflow from the tank would start to happen when the pump stopped after reaching high pressure. The back flow would continue until the pump restarted at the low pressure point. This cycling would continue as you described. Once I cleaned the check valve, everything (including the unloader valve) started working correctly. I hope this helps. And remember, don't work on these when they are under pressure and always wear safety glasses.

Sep 18, 2011 | Campbell Hausfeld Air Tools & Compressors

2 Answers


It sounds like the unload valve might be clogged up. Try taking it off anf cleaning it back up. If the compressor is older or has had a lot of use sometimnes when the rings wear oil and gunge will get into the valve and gum it up. good luck

Mar 10, 2011 | Air Tools & Compressors

1 Answer

I have a 5SR EP50SE compressor with an INTELLISYS controller the problem is when the set offline pressure is reached there is no voltage coming out from the controller to trigger the blowdown and the...

The blow down is a normally open valve so there will be no voltage when unloaded. When voltage is applied the blow down valve closes and the load solenoid opens allowing air to the inlet valve which should open. I suspect you have a bad load solenoid. If it leaks by it will keep the inlet valve open to some degree depending on how bad its leaking. If this is an older EP50SE you may have a spring in the bottom of the inlet valve that has broken. then there is not enough pressure to close the inlet valve. These are two common problems with this unit. Also if you look inside the controller panel there should be a wiring diagram. It should show 1SV and 3SV wired together. 1SV is the load solenoid and 3SV is the blow down valve. There is no unload solenoid. There is also a solenoid for line / sump pressure and a modulation solenoid.

Mar 07, 2011 | Ingersoll Rand Stationary Air Cooled...

1 Answer

Compressor wont restart because of head pressure

Piston air compressors have to unload to permit a restart, the two mot common types are an unloader valve or free air unloaders.

with an unloader valve this system uses a check valve mounted in the discharge line as it enters the tank, when the pump stops this check closes and does not permit the tank pressure to return to the pump. a unloader valve also opens to allow air pressure in the discharge line to vent, this valve is either on the pressure switch or on some models is on the pump, and is a centrifugal type.

Free air unloaders or head unloaders are a set of fingers that hold open the intake valves on the cylinders to permit the piston not to pump air against a head load, and once the pump is running the fingers retract to allow the pump to function as normal.

Jan 19, 2010 | Air Tools & Compressors

1 Answer

Compressor sounds like it's running under a large load and really slow. Blows circuit breaker eventually.

There is a line running from the pump assembly to the tank. At the tank the compressed air passes a check valve. This valve prevents the air from escaping back along the same line. After the tank reaches max psi the motor shuts off. What is undoubtedly happening or rather not happening with your compressor is the unloader valve is not functioning properly.

The unloader valve is what bleeds off the pressure that remain in the compression chamber after the motor shut off. If the unloader valve fails to bleed the excess psi off then the piston has to work against your minimum psi. or around 80psi.

This is your large load.
The unloader valve is comprised of a mechanical trigger at the switch and a small air line that runs from the switch back to the tank check valve or up at the pump manifold.

Often it is enough to clean the small mechanism and make sure all the small parts are free from corrosion or damage.
However you may need to replace it.
Hope this helps.

Nov 25, 2009 | Air Tools & Compressors

3 Answers

Low sump pressure

compressor shuts down on low sump pressure

Oct 19, 2009 | Ingersoll Rand Air Tools & Compressors

1 Answer

No air storage in the tank

so in another word your air compressor is mot pumping air.
(1) check for leaks
(2)check the air filter
(3) check the inlet valve
(4) if their is unloader valve (a) pressure switch
(b) load solenoid valve
(c) unloader valve

Sep 29, 2009 | Air Tools & Compressors

3 Answers

Compressor is loading without unloading

hi mate it could iver be a faulty load solenoid valve or the unloader its self is jaming up inside which means you have to strip it away from the air end and replace all the seals inside or give it to a specialst we are compressed air engineers we could sort it i will leave you a number call us anytime 07958354730 or call 01752 848801 many thanks

Jun 08, 2008 | Kano Technologies Atlas (K752HCDR) DVD+R...

Not finding what you are looking for?
Air Tools & Compressors Logo

Related Topics:

171 people viewed this question

Ask a Question

Usually answered in minutes!

Top Air Tools & Compressors Experts

John Trevino

Level 3 Expert

1388 Answers


Level 3 Expert

2528 Answers

Brad Brown

Level 3 Expert

17433 Answers

Are you an Air Tool and Compressor Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides