halocline
Contributor
The main thing to look for when you get it serviced is to make sure it's been tested on a flow bench to ensure proper flow.
Here, Read this:
Demystifying Regulator Repairs
I read that, it's basically an ad for an expensive tool that really does very little. It practically says as much if you read carefully. I think it's an interesting tool to evaluate flow characteristics and venturi effect, but since there's very little you can do once you set a reg's cracking effort, IP, and venturi assist in terms of increasing flow, what use does it have?
And, it's not really accurate for the design limits of a reg unless you have a serious air source with MUCH higher flow than a tank valve and the ability to maintain constant pressure.
You can tell a great deal about a reg's performance with an IP gauge, 2 tanks (one full, one near empty) and a sink full of water. To be honest, I couldn't care less if my D300s open at .7" or .9" of water. I just set them as low as I can get them and dive. For regs with more case fault geometry issues (like practically all conventional 2nd stages) the sink does a good job of helping you set cracking effort so that the reg is stable when the exhaust valve is shallower than the diaphragm. You just make sure the reg does not flow before the exhaust valve is submerged. (You can actually get away with a little lighter cracking effort, because differences in pressure/depth are greatest at the surface, but setting it this way ensures that case fault geometry will never cause the reg to freeflow)
Regulators operate in water, it makes sense to use water to test them. For me, the "main thing" is not that the tech has a machine to spit out numbers, but to make sure the tech has a good understanding of how the reg actually functions, and takes his/her time to do a thorough job of cleaning and careful reassembly.