Control Devices CS25-100 Cold Start Valve 1/4"

I have a new Rolair k17 pump and an old century 2hp motor. I’ve played with the pulley sizing to maximize the output on 120v to 9.0 cfm @40psi/7.4cfm @90psi. It pulls about 21amps right before cutout at 140psi. I was having trouble starting at 110psi below 50 degrees f. It would rotate slowly and pop the breaker. Changed to $25 synthetic oil, no change. Replaced the 40-year old motor start cap, no change. Put a pair of these start valves on a brass T on the pump output manifold. Bam. Problem totally solved. Not only does it start cold, but it starts easier at all temps now. These should be on every air compressor.

The threads on this item does not match exactly the threads on my Harbor Freight compressor however this is the one that HF said I should purchase. It appears that this did solve my problem with my compressor. Since the threads do not match I only gave this itme 4 stars.

Perfect for the horborfrieght compressor that make you think it is broke or you have to keep hitting the reset button. .Unscrew the old screw the new one on and go.

My air compressor was having issues kicking back on after the tank was full and then drops below the set pressure to fill it again. After checking my check valve which was still good I checked the capacitors and they were slightly out of tolerance. I replaced those but that didn’t fix it. I ended up buying two of these cold start valves and added them to my compressor pump line going into tank before the check valve. One didn’t work but using two allows the pump/motor to start up and push air into when it cycles back on to fill the tank full again.

Thank you to everyone that said to add a “T” with 2 of these! My harbor freight 21 gallon central pneumatic air compressor would not kick back on unless I drained the tank. I put one of these on just to test it and it still didn’t start, after adding the “T” with 2 of these in it, the compressor has been firing up every time without hesitation! Definitely order a “T” along with 2 of these valves and you’ll be all set!

Works great on central pneumatic 2.5 21 gallon from harbor freight

Worked great... but Central Pneumatic compressor sucks... 1 year and1 month old and its trash... Dam Harbor Frieght!

IT worked with the 10 gal from HF but it is longer so it sticks up about a 1/4 higher above the fin on the piston. Not and issue since it does not leak and works. I counted 4 threads vs two above the fin on the old part. Hope that helps. I bought due to hard starts at 30 degree. I also added Home Depot Kobalt all temp synthetic compressor oil.