How do you adjust a first stage

[diverrick]

Hi I am in an area where there are no fix it shop. I would like to know how to adjust the intermediate pressure in a first stage when you dont' have an intermediate pressure guage.

specifics. there is a free flow in the second stage due to intermediate pressure. we would adjust the second stage but would rather do it right.. well as right as we can without an intermediate guage.
other specifics.. it is a genisis reg.

 

[wedivebc]

Hi I am in an area where there are no fix it shop. I would like to know how to adjust the intermediate pressure in a first stage when you dont' have an intermediate pressure guage.

specifics. there is a free flow in the second stage due to intermediate pressure. we would adjust the second stage but would rather do it right.. well as right as we can without an intermediate guage.
other specifics.. it is a genisis reg.

it may be more likely IP creep caused by a leaking 1st stage hp seat. You need a gauge to be sure. These guys will sell you one http://scubatools.com/

 

[Cap335]

specifics. there is a free flow in the second stage due to intermediate pressure. we would adjust the second stage but would rather do it right.. well as right as we can without an intermediate guage.
other specifics.. it is a genisis reg.

After you get your int pressure gauge you will probably need a first stage kit
which will be harder to come across.

Randy

 

[Hoyden]

Order a copy of Vance Harlow's Scuba Regulator Maintenance and Repair. It is full of useful info of how to service and tune your regs. You can get an intermediate pressure gauge from Peter Built for $21.

Jackie

 

[DA Aquamaster]

I agree that an IP gauge is needed to address the problem, or at least to ensure that the freeflow is not the result of a worn and leaking HP seat that is causing excessive intermediate pressure.

You can build your own IP gauge pretty inexpensively. You need a run of the mill hardware store or Wal-mart variety air compressor guage (Campbell-Hausfield, etc.), a 1/4 npt to 1/4 npt nipple, a 1/4 npt to low pressure inflator quick disconnect adaptor from your LDS, and some teflon thread tape. The gauge then just plugs into your inflator hose.

Cost should be under $15.00.

If there is any IP creep at all you need to have the first stage rebuilt.

If the IP is solid but the second stage was never properly tuned to the first stage, then you have a couple options for adjustment. If the IP is at the upper end of the normal range (140-145 psi) lowering the IP may be an option as some first stages use an adjustable spring pad and IP can be adjusted externally. On others however, you may need to add or remove shims internally, and that gets a lot more complicated. You also do not want to lower the IP below the 140-145 psi range (with a full tank) if you are workign on an unbalanced piston first stage as IP will drop as tank pressure falls and you do not want to fall below 120 psi on a 500 psi tank.

The easier solution is normally to adjust the second stage to the first stage. There are however both single and dual adjustment designs floating around out there and the procedures for adjusting them are different.

To grossly oversimplify, with a single adjustment design, you normally only need to adjust the deoth of the orifice and the engineering and close tolerances of the rest of the parts ensure the lever will be at the proper height. On dual adjustment second stages you will have to adjust the orifice/seat engagement first, then adjust the lever for the proper height. The specifics very with different designs.

If you are determined to do it your self I would recommend Pete Wolfinger's Book "Regulator Savvy" from Peterbuilt tools (www.scubatools.com) or Vance Harlows book on reg repair from Airspeed Press.

 

[Al Mialkovsky]

Personally I'd rather have a tech do it for me

 

[Bob3]

Ditto on what DA AquaMaster says, you can easily slap together an IP gauge for dirt cheap, and not using one is for all practical purposes a "no go" situation.
If you can't find a male BC nipple, give me a PM & I can mail one to you. They're under $5.

 

[oxyhacker]

First stage IPs tend to be pretty solid unless someone starts messing with the reg who doesn't know what they are doing, or the HP seat starts failing. They may be off a bit in either direction, but this will rarely be enough to make a serious difference in how the reg performs. As DA says, its more important that the 2nd is tuned to the 1st.

Checking the IP, though, is one of the first steps in trouble shooting a misbehaving reg, and is non-invasive, so a gauge is well worth having - there's plans for a couple DIY ones on our website, at http://www.airspeedpress.com/regread.html

 

[Wayward Son]

I take it to Sea Divers and put it on George's bench, and wait for his expert handling of the beast.

But I don't think that's the answer you're looking for