CAT air compressor unloader valve

[wesst]

Reposting from general forum, as this may be electrical specific. I have a question someone may have an answer to regarding a new CAT air compressor.

The compressor runs fine upon start up and shuts off when full. It will restart when pressure drops as designed.
If I start the compressor and turn it off with the manual switch on the compressor at any psi less than max, the head pressure is relieved via the pressure unloader valve (CAT calls it the easy start valve) near the pump head. It works as intended.

I connected the air compressor to a switched garage outlet so I can turn it on and off from across the garage with a remote switch aligned with the lights switches for my garage. I did this with my old Craftsman air compressor and it worked great.

The issue I have with the new CAT compressor is if I shut the switch off before it reaches shut off pressure, the motor will not manually restart because pressure cannot be relieved from the pump head. The pressure will not bleed from the “easy start valve” located by the pump head when using the remote switch, but will if I walk to the compressor and manually turn it off at the actual pressure switch. My old Craftsman compressor would operate from the remote switch at any psi.

I am reaching out for insight from those more knowledgeable than myself as to why this will not operate from the remote switch. I was also looking into a load genie valve as well, but not sure if that would work. I thank you in advance for your time and feedback.

 

[American Locomotive]

It will not operate because the compressor is not starting from an unloaded state. The "relief" valve you hear is called an unloader.

Your old craftsman compressor either used a fixed orifice "bleed" to unload, or had leaky enough valves that the pressure would naturally bleed down while it was off.

You basically will have to leave the compressor on until it naturally cycles off. I think your only other real option would be to put a solenoid valve on the discharge line, but that's asking for trouble, IMO.

 

[The Cobbler]

the head is not unloading when you turn off the switch . it's hard on the motor to start it under that load, too.
the only way around it, as far as I know is install a normally open air valve solenoid as mentioned above, but while it's under warranty, I wouldn't start tampering with stuff.

 

[wyliesdiesels]

Reposting from general forum, as this may be electrical specific. I have a question someone may have an answer to regarding a new CAT air compressor.

The compressor runs fine upon start up and shuts off when full. It will restart when pressure drops as designed.
If I start the compressor and turn it off with the manual switch on the compressor at any psi less than max, the head pressure is relieved via the pressure unloader valve (CAT calls it the easy start valve) near the pump head. It works as intended.

I connected the air compressor to a switched garage outlet so I can turn it on and off from across the garage with a remote switch aligned with the lights switches for my garage. I did this with my old Craftsman air compressor and it worked great.

The issue I have with the new CAT compressor is if I shut the switch off before it reaches shut off pressure, the motor will not manually restart because pressure cannot be relieved from the pump head. The pressure will not bleed from the “easy start valve” located by the pump head when using the remote switch, but will if I walk to the compressor and manually turn it off at the actual pressure switch. My old Craftsman compressor would operate from the remote switch at any psi.

I am reaching out for insight from those more knowledgeable than myself as to why this will not operate from the remote switch. I was also looking into a load genie valve as well, but not sure if that would work. I thank you in advance for your time and feedback.

umm you already explained why it wont work. I highlighted it in red above

 

[wesst]

Thanks for the replies. I understand why it won’t restart, and looking for a solution to have it restart via remote switch.

I guess the question would be what is triggering the unloader valve to relieve pressure anytime the manual switch is switched to off (any point during a cycle) verses staying locked when I use the remote switch.

I believe the solution may be in the pressure switch, but I figured I would reach out to this group to see if anyone perhaps had had the same situation.

 

[American Locomotive]

The pressure switch is a mechanical device. When it clicks off, it opens the unloader valve that's built into it at the same time.

It does not ectrically open the unloader valve.

 

[dogdog]

Thanks for the replies. I understand why it won’t restart, and looking for a solution to have it restart via remote switch.

I guess the question would be what is triggering the unloader valve to relieve pressure anytime the manual switch is switched to off (any point during a cycle) verses staying locked when I use the remote switch.

I believe the solution may be in the pressure switch, but I figured I would reach out to this group to see if anyone perhaps had had the same situation.

Most air compressor have a cut in pressure and cut out pressure on the pressure switch.
Are you sure it is not because the air pressure is surging that range ?

 

[BillK]

What model number compressor ?

 

[wyliesdiesels]

Thanks for the replies. I understand why it won’t restart, and looking for a solution to have it restart via remote switch.

I guess the question would be what is triggering the unloader valve to relieve pressure anytime the manual switch is switched to off (any point during a cycle) verses staying locked when I use the remote switch.

I believe the solution may be in the pressure switch, but I figured I would reach out to this group to see if anyone perhaps had had the same situation.

As said above, its a mechanical connection inside the pressure switch

If you want this to work remotely, you would need to rig up an electrically controlled unloader valve