Ports on first stage

Ultimate Fly Fisher · Mar 14, 2006

Help please. Could anyone tell me how to distinguish between the high and low pressure ports on first stage. I'm getting a new computer and pressure guage to put on my first stage. I know I could just pull the old pressure hose off and replace with the new stuff but I would like to know how to distinguish between the two. One looks off set to the back and the rest look for of the valve assembly. Any help with identification of thw two would be very much appreciated. Thanx ahead of time.
Gerald :huh: :06:

Vie · Mar 14, 2006

They are differently sized... The LP ports (there are usually four of them) are usually 3/8" - the HP ports are bigger and have tiny pin hole openings (there should be only one or two HP ports on a first stage) - what first stage are you using?

Dive-aholic · Mar 15, 2006

Vie said it. It's the size that matters. But some 1st stages will also have numbers stamped around the HP ports that easily identify them.

redacted · Mar 15, 2006

Almost always they are different size and crossattachment is not possible. On some older 1st, like an early production scubapro Mk5, all ports were 3/8ths. Usually the HP ports are marked in some way. On Scubapro regs they are stamped HP. When you oppen an HP port, you should see a metal face in the bottom with a very small hole that restricts flow. An LP port will be fully open into the LP chambe so flow will not be restricted.

I doubt if you could get it wrong.

cerich · Mar 15, 2006

awap:
Almost always they are different size and crossattachment is not possible. On some older 1st, like an early production scubapro Mk5, all ports were 3/8ths. Usually the HP ports are marked in some way. On Scubapro regs they are stamped HP. When you oppen an HP port, you should see a metal face in the bottom with a very small hole that restricts flow. An LP port will be fully open into the LP chambe so flow will not be restricted.

I doubt if you could get it wrong.

had a dealer call me last week, one of their cust. got a Atom with hoseless transmitter, put an adapter on the transmitter then put the transmitter in a LP port. The call was why it didn't work to show tank pressure......

funny things can happen

redacted · Mar 15, 2006

cerich:
had a dealer call me last week, one of their cust. got a Atom with hoseless transmitter, put an adapter on the transmitter then put the transmitter in a LP port. The call was why it didn't work to show tank pressure......

funny things can happen

I actually thought of addressing that exception but decided it was unnesessary. I guess an old time cast iron pipe plumber might try filling any gaps with lead.

Murphy and Darwin sometimes work together.

Pyrofish · Mar 15, 2006

awap:
I actually thought of addressing that exception but decided it was unnesessary. I guess an old time cast iron pipe plumber might try filling any gaps with lead.

Murphy and Darwin sometimes work together.

That's why they make bushings!

Randy43068 · Mar 15, 2006

if you're connecting a gauge for HP try any port the hose fits into. You risk no damage doing so. If you connect the computer to a LP port it'll read low.

But as mentioned, you should be looking for the bigger ports.

Ultimate Fly Fisher · Mar 15, 2006

Thanx alot all. I have an older model Sherwood. Probably about 10-15 years old but in tip top conditon. I like it and it does what i need. Again thnk you for all the help. Keep wet.
Gerald

Ports on first stage

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