Air compressor pressure switch

[jacked_72]

I picked up a 230v 5hp 15a 60 gallon air compressor. I think the pressure switch is going since it doesn't seem to kick in at the right kick in pressure. I thought I'd just replace it since there appears to be a ton of cheap switches on the market. Digging a little deeper though, I see there is an amperage issue. These cheapie Lafoo switches seem to be advertised everywhere as taking 26A. Then you look at what the picture of the label says (no one actually posts specs) and it seems that most of them are 12a at 230v. I'm presuming that for my motor, I need 15A @230v or better (and maybe a lot better in a Chinese made part). The switch that is coming off is a Furnas CW-2075-52. I'm looking for a single port switch, 95-125psi, with an unloader.

I'm sure its not as complicated as I'm making it, but I don't want to burn something up. Any suggestions as to which switch is the correct replacement?

 

[454ragtop]

Well first off, that's not a 5 HP compressor, regardless what the label says, probably closer to 3 HP. But yes, you are correct, need at least a 15 amp rated switch, more the better. Or, convert to a mag starter and low draw pressure switch, the best way.

 

[redmondjp]

Don't buy a LeFoo. Get a Square-D one like this one:

https://www.amazon.com/dp/B0078RUFJ4/?tag=atomicindus08-20

Square D Schneider Electric model 9013FHG12J52M1X

 

[454ragtop]

Don't buy a LeFoo. Get a Square-D one like this one:

https://www.amazon.com/dp/B0078RUFJ4/?tag=atomicindus08-20

Square D Schneider Electric model 9013FHG12J52M1X

Don't think that one is up to the task, at least not without a mag starter, as it's only rated for 1.5 HP or less.

 

[tlmartin84]

Not to be a jerk, but did you try adjusting it?

Also you need to check the ACTUAL pressure and not the gauge reading on the tank. I just bought two harbor freight units. One read spot on with my Norgren Regulator, and the other was off 5-10 psi LOW.

I adjusted the gauge to get it reading right, and then adjusted the switch. The switch was adjusted at the factory. I kept blowing the pop off valve........they had it adjusted to high.

 

[redmondjp]

Don't think that one is up to the task, at least not without a mag starter, as it's only rated for 1.5 HP or less.

You're right - thanks for catching that - here is the higher-HP version of the same:

https://www.amazon.com/dp/B007IB29LW/?tag=atomicindus08-20

Square D Pumptrol 9013FHG32J52M1X

 

[guy48065]

The 90/125 Lefoo I bought could not be adjusted below the 150psi safety valve. The seller admitted they are **** but he has to sell them bc everyone else does (on eBay). I traded up to a Hubbell and it was perfect right out of the box.

 

[jacked_72]

Thanks for all the replies. I had looked all over the interweb for the Furnas model switch that is presently on the compressor and could find nothing about adjusting it. The modern switches seem to have two adjusting screws, one for the kick off pressure and one for the differential pressure. There is one screw on mine, but a slot for what would hold a second screw; there is no threads in the hole, so it doesn't appear that anything is missing. The screw that is there (which is metal) is in the bottom center of the switch and based on similar current production switches, I thought this was for the differential pressure. I had adjusted it a half turn earlier, but it didn't seem to do anything. Figuring the switch was junk anyway, I cranked that screw down 3 or 4 turns and it brought the cut in pressure to 95 (up from 50) and the cutout pressure to 120 (up from 110). So, it looks like it was just that the adjustment had been turned way down and that the switch has no differential adjustment. They guy I bought it from said he used it for painting and I'm thinking he might have used the pressure switch instead of a regulator to get the psi he wanted. The compressor did have a regulator on it, which in retrospect appears to be recent, so I never considered that the pressure switch was that far out of adjustment. I should have known from the other mickey mouse things on the compressor (lots of leaks and no pressure relief for the line cord) that something was amiss. Anyway, I'll watch the cut in and cut off pressure for a while and then make the call about a new switch. I don't want to rely on the over pressure relief valve doing its job.

Oh, and I didn't really think the motor was a true 5hp since its is an early 90s model before all the lawsuits over peak ratings on compressor motors. Its funny, there's a big sticker on the tank saying its 5hp, but nowhere does label on the motor make a HP claim.

Thanks for the input and it looks like tlmartin84 was spot on about the adjustment.