Hello Pablo, and thanks for sending in the photos. It makes understanding what you are questioning about on the website ASK page much easier to understand.
This is a custom compressed air regulator manifold, manufactured for or by your compressor manufacturer for their specific needs. There is nothing in this manifold that you cannot replace with standard, off the shelf components from a good hardware store that sells air compressors such as this.
NEW 1/2″ Compressed Air Filter Regulator/Desiccant Dryer/Coalescing Filter 3 Stages Combo
The item on the right in the photo above is the PRV valve.
Moving to the left, you have a standard, back mounted air gauge to show the pressure in the tank.
Under that appears to be a supply port that I believe is for feeding the compressed air from the tank into the compressor regulator manifold.
Next, you have the regulator itself. Here’s more info on compressed air regulators.
The gauge for this regulator has been mounted to the left of the regulator on the manifold. This gauge is the one that tells you what the pressure setting of that regulator is and shows you the pressure that the air tools downstream from the regulator will see. The regulator gauge reading will normally be lower than the tank gauge on the right that shows you the tank pressure.
The gauge that’s on the left can could also be relocated to threaded into the air port shown at the top of the regulator should you wish. Putting the gauge there will not affect it’s operation. I am guessing that your compressor manufacturer put the gauge on the left to balance out the look of their regulator manifold.
Threaded into the manifold below the gauge on the left is the air line coupler.
You indicate that one of the items on your manifold have failed.
I believe it won’t be the PRV on the right, as they don’t normally fail except by opening at too low a pressure, and if that were happening, it would be evident by the air flowing out of the PRV.
Check the price of the air compressor control switch with pressure regulator gauges on Amazon here
Either of the two gauges shown can be replaced by a low cost, probably 1/8 NPT back mounted air gauges, with a pressure reading of 0-150 or 0-200 or so on the face. I don’t recommend you to buy gauges with pressure readings under 150, as many general purpose DIY compressors can supply more air pressure than that, and you want to see the actual tank pressure which will be shown on the right hand gauge when the regulator manifold is reattached to your air compressor.
If your problem is the regulator itself, then your compressor manufacturer has made it difficult to remedy that, from what I’m able to see. It looks like they many have welded the regulator into the manifold.
You may need to replace everything then, and if that’s the case, go to the hardware store with this complete unit in your hand, and tell the clerk that you want to build the same manifold using copper pipe and copper fittings. All of the parts you need will normally be off the shelf. You will need to be able to “sweat” copper to solder the fittings into the pipe manifold. If you have that skill, then rebuilding this manifold from scratch should be pretty easy.
The new regulator will have a threaded port on the right and left sides, and you’ll need to get that same size thread in copper to thread into the regulator.
The coupler will unscrew off the existing manifold, and make sure that the fitting you buy to replace the original is the same size as the one that’s there now.
When you reassemble, make sure that 1) you have the PRV installed 2) that you pull out and push back on the PRV ring to make sure the PRV moves freely so it can vent air should the system over pressurize.