REGULATOR PR

REGULATOR PR 2670 7845 74 is usually there to keep the air or hydraulic pressure steady for a specific function, like the feed motor or the rock drill percussion. It takes whatever fluctuating pressure comes in from the compressor or pump and knocks it down to a consistent, usable level. This is pretty critical for things that need a steady push, otherwise, you get all sorts of weird behavior and inconsistent operation out of that particular circuit.

When this thing starts to go bad, you'll usually notice it in the system it's supposed to be regulating. Say it's on the percussion circuit; you might hear the drill hammer hitting inconsistently, or the feed might surge and then slow down. Sometimes, the pressure gauge downstream will just start bouncing all over the place, or it'll read low even when the main supply is fine. It's a dead giveaway that the internal diaphragm or spring is shot, and it just can't hold a steady setpoint anymore.

Replacing one of these isn't usually a huge job, but make sure you relieve all the system pressure first – sounds obvious, but you'd be surprised how many guys forget. When you pull it out, always check the inlet screen or filter right before it; those often get clogged up and can cause the regulator to act funny, making you think it's bad when it's just starving for flow. A lot of guys forget that little screen, and it's usually the culprit.