RS-110 question

[schlosrat]

I started a thread about a question I've got in another part of this forum, but I was kindly referred over here since my question is about a TUSA reg. The original thread is here http://www.scubaboard.com/forums/regulators/291666-regulator-port-question.html

Basically, I bought this reg and expected it to have 6 ports: 2 HP and 4 LP. It's got those all right; but it's also got two more undocumented ports (by undocumented, I mean there is no mention of them on any website I've seen, or in the owners manual that came with the reg). The undocumented ports are labeled EP, and their port plugs are very significantly different than either the HP or LP port plugs. The EP port plugs appear to be the same diameter as the LP port plugs, except they have a finer thread pitch. Also the port plugs take a larger size Allen wrench than either HP or LP port plugs. But most disturbing is the fact that the damn plugs are hollow! So basically, even with the plugs in place the insides of my first stage are open to air and water.

There are pictures of all these things on the other thread I started, if that's any help.

What are the EP ports for? What am I supposed to do with them? Can I dive with this reg with the EP ports as they are now and not risk drowning or venting all my air through them? It sure would be nice if the documentation that came with the reg, or the info on the TUSA website for that matter, actually spoke about these guys instead of leaving them as a surprise.

Stumped in Tucson,
Steve

 

[schlosrat]

Update:

I took the reg down to my LDS (The Dive Shop in Tucson) and their theory was that the EP ports were required by the design to allow ambient pressure on some part of the piston. They hooked it up to a tank and turned on the air and it appeared to behave like any normal reg would, e.g. air was not rushing out of the hollow EP port plugs. I suppose that with this design of regulator it will be particularly important to clean it thoroughly each time I dive, especially if there were a lot of solids suspended in the water like in a lake or diving a kelp bed, etc.

I'm still very interested in hearing from anyone at TUSA or who knows about these regs regarding what the EP ports are really for. Why do they have threaded hollow plugs? Is there some sort of gear that can be attached there? What about a filter to keep out particulate material? What is the recommended cleaning for this reg if you've dived in murky water? Do I need to pull out the EP port plugs and flush thoroughly with fresh water or is a normal soaking in a fresh water tub sufficient?

Also, for TUSA, wouldn't it be a nice thing if the manual that ships with this reg answered some of these questions? Or if this sort of thing were addressed on a web page on your corporate site? (hint, hint)

Steve

 

[TUSA]

Hello,
There are two types of first stage regulators used for scuba, Piston and Diaphragm. A Piston first stage has ambient pressure ports (EP) allowing it to balance itself to the surrounding pressure (various depths) while in use. Sea water or fresh water, depending on what you are diving in, must enter the first stage body (through the ambient “EP” pressure ports) to counter act with the spring and piston balancing the first stage to its surrounding pressure. The ambient pressure ports must not be sealed. The TUSA R-100 first stage is a Piston first stage regulator. The ambient pressure ports should not be plugged. The ambient pressure ports can not be used for High pressure or low pressure hoses as they do not flow any air. Proper care and maintenance for your TUSA R-100 first stage is to soak it in fresh, clean water allowing the water to flow in and out of the ambient pressure ports. There are no adapters or filters to be used with these ports. TUSA does not have an environmental kit for the R-100 first stage. Thank you.

 

[schlosrat]

Thanks for the explanation! It's good to know what those guys are for and I'll be sure to keep them clear and clean. I do find myself wondering why they have hollow plugs in them and also why they're threaded. I understand that the hollow plugs they came with will permit ambient pressure to get in at those points; but given what you say that they must be kept open for the piston to work, then why put *any* sort of plug in them - hollow or otherwise? Why not simply have untapped ports without the hollow plugs in them? Wouldn't that be simpler? What purpose does it serve to have a tapped hole with a hollow plug in it instead of an untapped hole without anything in it?

Thanks,
Steve

 

[Ed Palma]

Cleaning out the ambient pressure chamber will be easier, i think.