Used GA-90 Remote Start/Stop Circuit

by Dennis Vinas
(Batavia, IL. USA)

GA-90 Remote Start/Stop Circuit Diagram

GA-90 Remote Start/Stop Circuit Diagram

GA-90 Remote Start/Stop Circuit Diagram
GA-90 Remote Start/Stop Circuit

We acquired a used GA-90 SN: AIF .079712 a couple of months ago. I installed the compressor and coupled the outlet port to 2-250 gallon air-holding tanks (in parallel) and output to a brand new Atlas Copco FX-15 Air Dryer. Compressor has been running seamlessly since I first started it in mid-August/2016.
I ran a remote Start/Stop, E-stop station outside of the compressor room. In remote mode, I can start the compressor but it won't put out any air. I switched back to Local control mode and the compressor puts out air normally as before.
Can anyone tell me what I am missing? I have attached a screenshot drawing for the start/stop and E-stop circuit I added. The E-stop has 2 normally closed contact blocks. The Start pushbutton was initially a momentary NO contact block because the book says not to use a maintained-action button. I switched that to a maintained NO contact when I noticed on my first attempt to start that as soon as I released the start button, the compressor stops. Do I need remote load and unload feedback to the control unit as well?

Thank you for taking the time to read through this.

Comments for Used GA-90 Remote Start/Stop Circuit

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Oct 19, 2016
Remote start/stop circuit
by: Dennis

I am attaching a drawing I made for the Remote Start/Stop circuit and Remote E-Stop I added to our Atlas Copco GA-90...it works like a charm.

(Please start a new thread, refer to this one in the comment, and you can upload up to 4 photos. I'll move them here.)

Sep 28, 2016
Remote Start/Stop
by: Dennis

Atlas Copco GA-90 stops using its resident Load/Unload Pressure Switch as soon as it is set for Remote Start/Stop so I had to put in a pressure switch with a deadband of 85 PSI and a switch point of 107 PSI downstream of the Air Dryer, right before air flows to the rest of the building.

The E-stop circuit (2-chains; 120VAC and 24VAC) stays active in any mode; Local or Remote control. I would have uploaded my .pdf schematic but the site only supports photos.

(Dennis, send an email via the contact form, and I'll be in touch with an address you can send a .pdf. I'll be happy to upload it here for you.)

Sep 24, 2016
Remote Start - Stop
by: Doug in s.d.ca

I suspect your last sentence is your answer.

But I can't really read the drawings - too compressed.

Perhaps you can send better quality to Bill directly, and he can forward them to me.

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