Blocked positive pressure valve in first stage

[axxel57]

Keyshunter, thanks for clarifying this.
The filter is only helping to prevent blockage from the tank side. Here the problem is that the diving staff is not rinsing the Sherwood regulators while still under pressure. They are just thrown in the fresh water basin and left there for a while. Sooner or later water is entering from this basin through the one way bleed valve into the main spring chamber and is clogging the flow restrictor screw from that side, so the filter doesn't help.
Anyway it's not a regulator type for bigger diving operations.......

 

[miguelation]

What I did, since the clogging was probably due from lubricating the "O"rings and or salt water intrussion, I first washed the piston (w/o Orings and HP seal, off course) in boiling water in the microwave for 5 minutes, then, I put the piston a top the electric stove (mine has glass top, I would not do it on gas or anything else) for another 5 minutes in high, and it worked. I guess the high heat burned off the Christo lube left over. The only problem was, that the piston got tarnish blue, but I rubbed it off with a hand towel. Make sure that next time don't put lubricant over the fixed orifice.

Good luck.

 

[SDAnderson]

The book says to replace them. If you're far enough off the rails to ignore the book, sometimes you can ultrasonically clean the filter, especially if you use a 9 step process:

1. Say a prayer to the gods of the deep and pour half a bottle of beer down the drain. OK, maybe only 1/4 bottle but don't get stingy - the gods can punish, too.
2. Drink the rest of the beer. You're gonna need it by the time you're done with this.
3. Hand scrub the entire piston as clean as you possibly can using whatever favorite detergent and a plastic bristle (tooth) brush and cotton swabs.
4. Rinse with tap water or distilled water. Use lots of running water.
5. Fill an ultrasonic with a clean solution of a serious degreaser. Blue Gold works well, Crystal Simple Green is also good, I don't like dish detergent for this.
6. Rinse well with lots of distilled water. Let it soak for several minutes.
7. Back to the ultrasonic with a clean batch of a mild phosphoric acid. Global sells some good stuff, distilled white vinegar is less predictable. Do NOT use canning vinegar - way too acidic.
8. Rinse well with lots of distilled water. Let it soak for several minutes.
9. Blow dry with clean air. Don't be too gentle.
   

The same process sometimes works on the laser-drilled screw. The operative word here is "sometimes." All in all, a couple years of experimenting in the repair room have shown that it's faster/better/more reliable/cheaper to replace the thing but this is the DIY forum, so good luck.