We have a Champion compressor (twin 10hp recip on horizontal tank) with the stock oil/air separator and air filters that come with them. We have a problem with tiny rust particles getting stuck in the tiny float switches on the bottom of these and frequently get stuck bleeding air out, sometimes emptying the tank overnight.

These two filters are installed between the dryer and the tank. The oil separator is installed prior to the air filter. I'm pretty sure we've had both of these get stuck bleeding air out of the float switch before.

We are definitely in a humid environment, but we have the tank's auto-drain set to a very aggressive purge, so we aren't puddling water in the tank more than maybe a cup or so at any given time, which isn't much.

We still seem to get dirt or rust plugging those float switches.

I'm looking for suggestions here on how to correct this. We've had this happen literally the same day we've disassembled and cleaned them and manually checked the tank for condensation.

The local company we purchased the Champion from hasn't been much help, they just say "make sure your tank is drained" which we already do.

Had another compressor company also kinda baffled, their only suggestion was to add a second vertical tank next to it to act as additional compressed air sink and "catch can" with another auto-drain, which I dislike for obvious reasons.

Thoughts?

Forgive me if this is the wrong forum for this, I misread the name of this forum as "dust collection, safety, and plant operations".

In my experience the rust was coming from black iron pipe fittings right off the compressor outlet. Try changing to brass and other non rusting components to solve the real problem.

Tom, that's a good point. Thankfully we aren't using black iron pipe anywhere on our system, we are using a rubber hose whip to go from the tank to the oil separator, and after the air dryer we're using the 1" aluminum fast-pipe stuff.

Our old system had black iron, which had it's pitfalls like you say.

My compressor, it goes pump, dryer (which has its own auto drain), tank, oil separator, another filter, then the system.

I get some water in the tank from short cycling the compressor, but not much.

Are the drain valves in your setup always under pressure? I ask because one on my router is a little cranky.
I let the system drain down every night. Tank included. Just made me wonder if that were a potential cause there. I don't know why it would be, just spitballing ideas.

I have a big ball valve at the main tank that I turn off each night. I the leave the tank pressurized. It won't solve your problem but it will reduce the morning run time to pump up the system.
The rust might be coming from the end fittings of the flex hose.