Matheson 8-320 Regulator help - The Planted Tank Forum
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post #1 of 4 (permalink) Old 10-03-2012, 11:24 PM Thread Starter
Algae Grower
Join Date: Oct 2012
Location: Canada
Posts: 11
Matheson 8-320 Regulator help

Hi all,

I bought a Matheson 8-320 CO2 regulator on ebay and i'm having some trouble identifying the connectors coming out of it. I've read online that it can either have the 1/4" NPT connector or a weirdly threaded monstrosity that requires an adapter of some kind. Is mine 1/4" NPT or the other?

The pictures are as follows:

1) the regulator itself
2) the part that goes to the tank - what is the white plastic stuff capped inside? is that a stopper that I have to remove?
3)the low pressure output side - is this 1/4" npt?
4)a valve that came with it that was in the low pressure output - I removed it.

Help me plantedtank forum, you are my only hope.
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post #2 of 4 (permalink) Old 10-03-2012, 11:36 PM
Plant Clown
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Join Date: Sep 2010
Location: Greensboro, NC
Posts: 4,729
The third picture is a high flow valve. Most industrial regs come with them, and they're useless to us. You can junk it.

The outlet is 1/4" NPT.

The inlet is either 1/4" NPT or 1/2"-27, but you won't know until you remove the one that's on there, which may or may not be necessary. My guess is that it's not possible to slide the nut down the nipple - I have one or two like that - so you'll have to use a pipe wrench or locking pliers on the nipple shaft if you want to remove it. As far as the plastic gunk in the orifice, you'll need to remove it. It's probably the remnants of the last nylon washer it was used with, that somehow got down there. If you can't remove it, you'll need to replace the nipple. If you can remove the gunk, and you don't find a leak along the nipple, then you're fine and don't have to worry about removing the nipple.

By the way, the "weirdly threaded monstrosity" that the inlet threads probably are is a simple fix, if you even need to go there. Western Enterprises part CO-7, I think, is the 1/2-27 threaded nipple, and costs all of a dollar or two more than a standard 1/4 nipple. They both use the same nut.
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post #3 of 4 (permalink) Old 10-03-2012, 11:58 PM Thread Starter
Algae Grower
Join Date: Oct 2012
Location: Canada
Posts: 11
Thanks buddy, I'm glad the outlet is 1/4" npt, that makes things easier for finding parts. Any recommendations of companies that sell pipe fittings online? I'm not very mechanically inclined, what are te specific names of the parts? What will convert 1/4" to 1/8"? I assume I'll need a 45 degree elbow from the outlet to the solenoid if I want it straight for my jbj bubble counter, right?
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post #4 of 4 (permalink) Old 10-04-2012, 12:08 AM
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Location: Greensboro, NC
Posts: 4,729
I do almost all my general parts shopping with Evilbay, and most of my specific parts (stainless adapters, for example), through online sellers (Swagelok, Clippard, etc.). Just do an Evilbay search for "brass adapter 1/4 1/8 npt" or some variation and you'll come up with plenty of options. Just make sure the description says nothing about "tube", "ISO", "flare" "BSP", or any other type of fitting. It should all be NPT, FNPT, or MNPT. And keep everything 1/8" after the initial adapter if possible.

No, you don't need a 45 degree elbow. A standard 90 degree elbow will just as easily turn from 9 o'clock (if the reg face were a clock) to straight forward, as it will from 7 o'clock to straight forward. Do a search for VTS250 co2 regulator images and you'll see what I mean.

Feel free to PM with specific questions - I've built several rigs with that model.
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co2, diy, matheson, regulator

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